CFR / Title 40 / Part 136 / Sec. 136.7 Quality assurance and quality control.

The permittee/laboratory shall use suitable QA/QC procedures when conducting compliance analyses with any part 136 chemical method or an alternative method specified by the permitting authority. These QA/QC procedures are generally included in the analytical method or may be part of the methods compendium for approved Part 136 methods from a consensus organization. For example, Standard Methods contains QA/QC procedures in the Part 1000 section of the Standard Methods Compendium. The permittee/laboratory shall follow these QA/QC procedures, as described in the method or methods compendium. If the method lacks QA/QC procedures, the permittee/laboratory has the following options to comply with the QA/QC requirements:

(a) Refer to and follow the QA/QC published in the ``equivalent'' EPA method for that parameter that has such QA/QC procedures;

(b) Refer to the appropriate QA/QC section(s) of an approved part 136 method from a consensus organization compendium;

(c)(1) Incorporate the following twelve quality control elements, where applicable, into the laboratory's documented standard operating procedure (SOP) for performing compliance analyses when using an approved part 136 method when the method lacks such QA/QC procedures. One or more of the twelve QC elements may not apply to a given method and may be omitted if a written rationale is provided indicating why the element(s) is/are inappropriate for a specific method.

(1) Incorporate the following twelve quality control elements, where applicable, into the laboratory's documented standard operating procedure (SOP) for performing compliance analyses when using an approved part 136 method when the method lacks such QA/QC procedures. One or more of the twelve QC elements may not apply to a given method and may be omitted if a written rationale is provided indicating why the element(s) is/are inappropriate for a specific method.

(i) Demonstration of Capability (DOC);

(ii) Method Detection Limit (MDL);

(iii) Laboratory reagent blank (LRB), also referred to as method blank (MB);

(iv) Laboratory fortified blank (LFB), also referred to as a spiked blank, or laboratory control sample (LCS);

(v) Matrix spike (MS) and matrix spike duplicate (MSD), or laboratory fortified matrix (LFM) and LFM duplicate, may be used for suspected matrix interference problems to assess precision;

(vi) Internal standards (for GC/MS analyses), surrogate standards (for organic analysis) or tracers (for radiochemistry);

(vii) Calibration (initial and continuing), also referred to as initial calibration verification (ICV) and continuing calibration verification (CCV);

(viii) Control charts (or other trend analyses of quality control results);

(ix) Corrective action (root cause analysis);

(x) QC acceptance criteria;

(xi) Definitions of preparation and analytical batches that may drive QC frequencies; and

(xii) Minimum frequency for conducting all QC elements.

(2) These twelve quality control elements must be clearly documented in the written standard operating procedure for each analytical method not containing QA/QC procedures, where applicable. [77 FR 29813, May 18, 2012]

Sec. Appendix A to Part 136--Methods for Organic Chemical Analysis of

Municipal and Industrial Wastewater

Method 601--Purgeable Halocarbons

1. Scope and Application

1.1 This method covers the determination of 29 purgeable halocarbons.

The following parameters may be determined by this method: ------------------------------------------------------------------------

STORET

Parameter No. CAS No.------------------------------------------------------------------------Bromodichloromethane........................... 32101 75-27-4Bromoform...................................... 32104 75-25-2Bromomethane................................... 34413 74-83-9Carbon tetrachloride........................... 32102 56-23-5Chlorobenzene.................................. 34301 108-90-7Chloroethane................................... 34311 75-00-32-Chloroethylvinyl ether....................... 34576 100-75-8Chloroform..................................... 32106 67-66-3Chloromethane.................................. 34418 74-87-3Dibromochloromethane........................... 32105 124-48-11,2-Dichlorobenzene............................ 34536 95-50-11,3-Dichlorobenzene............................ 34566 541-73-11,4-Dichlorobenzene............................ 34571 106-46-7Dichlorodifluoromethane........................ 34668 75-71-81,1-Dichloroethane............................. 34496 75-34-31,2-Dichloroethane............................. 34531 107-06-21,1-Dichloroethane............................. 34501 75-35-4trans-1,2-Dichloroethene....................... 34546 156-60-51,2-Dichloropropane............................ 34541 78-87-5cis-1,3-Dichloropropene........................ 34704 10061-01-5trans-1,3-Dichloropropene...................... 34699 10061-02-6Methylene chloride............................. 34423 75-09-21,1,2,2-Tetrachloroethane...................... 34516 79-34-5Tetrachloroethene.............................. 34475 127-18-41,1,1-Trichloroethane.......................... 34506 71-55-61,1,2-Trichloroethane.......................... 34511 79-00-5Tetrachloroethene.............................. 39180 79-01-6Trichlorofluoromethane......................... 34488 75-69-4Vinyl chloride................................. 39715 75-01-4------------------------------------------------------------------------

1.2 This is a purge and trap gas chromatographic (GC) method applicable to the determination of the compounds listed above in municipal and industrial discharges as provided under 40 CFR 136.1. When this method is used to analyze unfamiliar samples for any or all of the compounds above, compound identifications should be supported by at least one additional qualitative technique. This method describes analytical conditions for a second gas chromatographic column that can be used to confirm measurements made with the primary column. Method 624 provides gas chromatograph/mass spectrometer (GC/MS) conditions appropriate for the qualitative and quantitative confirmation of results for most of the parameters listed above.

1.3 The method detection limit (MDL, defined in Section 12.1) \1\ for each parameter is listed in Table 1. The MDL for a specific wastewater may differ from those listed, depending upon the nature of interferences in the sample matrix.

1.4 Any modification of this method, beyond those expressly permitted, shall be considered as a major modification subject to application and approval of alternate test procedures under 40 CFR 136.4 and 136.5.

1.5 This method is restricted to use by or under the supervision of analysts experienced in the operation of a purge and trap system and a gas chromatograph and in the interpretation of gas chromatograms. Each analyst must demonstrate the ability to generate acceptable results with this method using the procedure described in Section 8.2.

2. Summary of Method

2.1 An inert gas is bubbled through a 5-mL water sample contained in a specially-designed purging chamber at ambient temperature. The halocarbons are efficiently transferred from the aqueous phase to the vapor phase. The vapor is swept through a sorbent trap where the halocarbons are trapped. After purging is completed, the trap is heated and backflushed with the inert gas to desorb the halocarbons onto a gas chromatographic column. The gas chromatograph is temperature programmed to separate the halocarbons which are then detected with a halide-specific detector. \2 3\

2.2 The method provides an optional gas chromatographic column that may be helpful in resolving the compounds of interest from interferences that may occur.

3. Interferences

3.1 Impurities in the purge gas and organic compounds outgassing from the plumbing ahead of the trap account for the majority of contamination problems. The analytical system must be demonstrated to be free from contamination under the conditions of the analysis by running laboratory reagent blanks as described in Section 8.1.3. The use of non-Teflon plastic tubing, non-Teflon thread sealants, or flow controllers with rubber components in the purge and trap system should be avoided.

3.2 Samples can be contaminated by diffusion of volatile organics (particularly fluorocarbons and methylene chloride) through the septum seal ilto the sample during shipment and storage. A field reagent blank prepared from reagent water and carried through the sampling and handling protocol can serve as a check on such contamination.

3.3 Contamination by carry-over can occur whenever high level and low level samples are sequentially analyzed. To reduce carry-over, the purging device and sample syringe must be rinsed with reagent water between sample analyses. Whenever an unusually concentrated sample is encountered, it should be followed by an analysis of reagent water to check for cross contamination. For samples containing large amounts of water-soluble materials, suspended solids, high boiling compounds or high organohalide levels, it may be necessary to wash out the purging device with a detergent solution, rinse it with distilled water, and then dry it in a 105 [deg]C oven between analyses. The trap and other parts of the system are also subject to contamination; therefore, frequent bakeout and purging of the entire system may be required.

4. Safety

4.1 The toxicity or carcinogenicity of each reagent used in this method has not been precisely defined; however, each chemical compound should be treated as a potential health hazard. From this viewpoint, exposure to these chemicals must be reduced to the lowest possible level by whatever means available. The laboratory is responsible for maintaining a current awareness file of OSHA regulations regarding the safe handling of the chemicals specified in this method. A reference file of material data handling sheets should also be made available to all personnel involved in the chemical analysis. Additional references to laboratory safety are available and have been identified \4 6\ for the information of the analyst.

4.2 The following parameters covered by this method have been tentatively classified as known or suspected, human or mammalian carcinogens: carbon tetrachloride, chloroform, 1,4-dichlorobenzene, and vinyl chloride. Primary standards of these toxic compounds should be prepared in a hood. A NIOSH/MESA approved toxic gas respirator should be worn when the analyst handles high concentrations of these toxic compounds.

5. Apparatus and Materials

5.1 Sampling equipment, for discrete sampling.

5.1.1 Vial--25-mL capacity or larger, equipped with a screw cap with a hole in the center (Pierce 13075 or equivalent). Detergent wash, rinse with tap and distilled water, and dry at 105 [deg]C before use.

5.1.2 Septum--Teflon-faced silicone (Pierce 12722 or equivalent). Detergent wash, rinse with tap and distilled water, and dry at 105 [deg]C for 1 h before use.

5.2 Purge and trap system--The purge and trap system consists of three separate pieces of equipment: a purging device, trap, and desorber. Several complete systems are now commercially available.

5.2.1 The purging device must be designed to accept 5-mL samples with a water column at least 3 cm deep. The gaseous head space between the water column and the trap must have a total volume of less than 15 mL. The purge gas must pass through the water column as finely divided bubbles with a diameter of less than 3 mm at the origin. The purge gas must be introduced no more than 5 mm from the base of the water column. The purging device illustrated in Figure 1 meets these design criteria.

5.2.2 The trap must be at least 25 cm long and have an inside diameter of at least 0.105 in. The trap must be packed to contain the following minimum lengths of adsorbents: 1.0 cm of methyl silicone coated packing (Section 6.3.3), 7.7 cm of 2,6-diphenylene oxide polymer (Section 6.3.2), 7.7 cm of silica gel (Section 6.3.4), 7.7 cm of coconut charcoal (Section 6.3.1). If it is not necessary to analyze for dichlorodifluoromethane, the charcoal can be eliminated, and the polymer section lengthened to 15 cm. The minimum specifications for the trap are illustrated in Figure 2.

5.2.3 The desorber must be capable of rapidly heating the trap to 180 [deg]C. The polymer section of the trap should not be heated higher than 180 [deg]C and the remaining sections should not exceed 200 [deg]C. The desorber illustrated in Figure 2 meets these design criteria.

5.2.4 The purge and trap system may be assembled as a separate unit or be coupled to a gas chromatograph as illustrated in Figures 3 and 4.

5.3 Gas chromatograph--An analytical system complete with a temperature programmable gas chromatograph suitable for on-column injection and all required accessories including syringes, analytical columns, gases, detector, and strip-chart recorder. A data system is recommended for measuring peak areas.

5.3.1 Column 1--8 ft long x 0.1 in. ID stainless steel or glass, packed with 1% SP-1000 on Carbopack B (60/80 mesh) or equivalent. This column was used to develop the method performance statements in Section 12. Guidelines for the use of alternate column packings are provided in Section 10.1.

5.3.2 Column 2--6 ft long x 0.1 in. ID stainless steel or glass, packed with chemically bonded n-octane on Porasil-C (100/120 mesh) or equivalent.

5.3.3 Detector--Electrolytic conductivity or microcoulometric detector. These types of detectors have proven effective in the analysis of wastewaters for the parameters listed in the scope (Section 1.1). The electrolytic conductivity detector was used to develop the method performance statements in Section 12. Guidelines for the use of alternate detectors are provided in Section 10.1.

5.4 Syringes--5-mL glass hypodermic with Luerlok tip (two each), if applicable to the purging device.

5.5 Micro syringes--25-[micro]L, 0.006 in. ID needle.

5.6 Syringe valve--2-way, with Luer ends (three each).

5.7 Syringe--5-mL, gas-tight with shut-off valve.

5.8 Bottle--15-mL, screw-cap, with Teflon cap liner.

5.9 Balance--Analytical, capable of accurately weighing 0.0001 g.

6. Reagents

6.1 Reagent water--Reagent water is defined as a water in which an interferent is not observed at the MDL of the parameters of interest.

6.1.1 Reagent water can be generated by passing tap water through a carbon filter bed containing about 1 lb of activated carbon (Filtrasorb-300, Calgon Corp., or equivalent).

6.1.2 A water purification system (Millipore Super-Q or equivalent) may be used to generate reagent water.

6.1.3 Reagent water may also be prepared by boiling water for 15 min. Subsequently, while maintaining the temperature at 90 [deg]C, bubble a contaminant-free inert gas through the water for 1 h. While still hot, transfer the water to a narrow mouth screw-cap bottle and seal with a Teflon-lined septum and cap.

6.2 Sodium thiosulfate--(ACS) Granular.

6.3 Trap Materials:

6.3.1 Coconut charcoal--6/10 mesh sieved to 26 mesh, Barnabey Cheney, CA-580-26 lot M-2649 or equivalent.

6.3.2 2,6-Diphenylene oxide polymer--Tenax, (60/80 mesh), chromatographic grade or equivalent.

6.3.3 Methyl silicone packing--3% OV-1 on Chromosorb-W (60/80 mesh) or equivalent.

6.3.4 Silica gel--35/60 mesh, Davison, grade-15 or equivalent.

6.4 Methanol--Pesticide quality or equivalent.

6.5 Stock standard solutions--Stock standard solutions may be prepared from pure standard materials or purchased as certified solutions. Prepare stock standard solutions in methanol using assayed liquids or gases as appropriate. Because of the toxicity of some of the organohalides, primary dilutions of these materials should be prepared in a hood. A NIOSH/MESA approved toxic gas respirator should be used when the analyst handles high concentrations of such materials.

6.5.1 Place about 9.8 mL of methanol into a 10-mL ground glass stoppered volumetric flask. Allow the flask to stand, unstoppered, for about 10 min or until all alcohol wetted surfaces have dried. Weigh the flask to the learest 0.1 mg.

6.5.2 Add the assayed reference material:

6.5.2.1 Liquid--Using a 100 [micro]L syringe, immediately add two or more drops of assayed reference material to the flask, then reweigh. Be sure that the drops fall directly into the alcohol without contacting the neck of the flask.

6.5.2.2 Gases--To prepare standards for any of the six halocarbons that boil below 30 [deg]C (bromomethane, chloroethane, chloromethane, dichlorodifluoromethane, trichlorofluoromethane, vinyl chloride), fill a 5-mL valved gas-tight syringe with the reference standard to the 5.0-mL mark. Lower the needle to 5 mm above the methanol meniscus. Slowly introduce the reference standard above the surface of the liquid (the heavy gas will rapidly dissolve into the methanol).

6.5.3 Reweigh, dilute to volume, stopper, then mix by inverting the flask several times. Calculate the concentration in [micro]g/[micro]L from the net gain in weight. When compound purity is assayed to be 96% or greater, the weight can be used without correction to calculate the concentration of the stock standard. Commercially prepared stock standards can be used at any concentration if they are certified by the malufacturer or by an independent source.

6.5.4 Transfer the stock standard solution into a Teflon-sealed screw-cap bottle. Store, with minimal headspace, at -10 to -20 [deg]C and protect from light.

6.5.5 Prepare fresh standards weekly for the six gases and 2-chloroethylvinyl ether. All other standards must be replaced after one month, or sooner if comparison with check standards indicates a problem.

6.6 Secondary dilution standards--Using stock standard solutions, prepare secondary dilution standards in methanol that contain the compounds of interest, either singly or mixed together. The secondary dilution standards should be prepared at concentrations such that the aqueous calibration standards prepared in Section 7.3.1 or 7.4.1 will bracket the working range of the analytical system. Secondary dilution standards should be stored with minimal headspace and should be checked frequently for signs of degradation or evaporation, especially just prior to preparing calibration standards from them.

6.7 Quality control check sample concentrate--See Section 8.2.1.

7. Calibration

7.1 Assemble a purge and trap system that meets the specifications in Section 5.2. Condition the trap overnight at 180 [deg]C by backflushing with an inert gas flow of at least 20 mL/min. Condition the trap for 10 min once daily prior to use.

7.2 Connect the purge and trap system to a gas chromatograph. The gas chromatograph must be operated using temperature and flow rate conditions equivalent to those given in Table 1. Calibrate the purge and trap-gas chromatographic system using either the external standard technique (Section 7.3) or the internal standard technique (Section 7.4).

7.3 External standard calibration procedure:

7.3.1 Prepare calibration standards at a miminum of three concentration levels for each parameter by carefully adding 20.0 [micro]L of one or more secondary dilution standards to 100, 500, or 1000 [micro]L of reagent water. A 25-[micro]L syringe with a 0.006 in. ID needle should be used for this operation. One of the external standards should be at a concentration near, but above, the MDL (Table 1) and the other concentrations should correspond to the expected range of concentrations found in real samples or should define the working range of the detector. These aqueous standards can be stored up to 24 h, if held in sealed vials with zero headspace as described in Section 9.2. If not so stored, they must be discarded after 1 h.

7.3.2 Analyze each calibration standard according to Section 10, and tabulate peak height or area responses versus the concentration in the standard. The results can be used to prepare a calibration curve for each compound. Alternatively, if the ratio of response to concentration (calibration factor) is a constant over the working range (<10% relative standard deviation, RSD), linearity through the origin can be assumed and the average ratio or calibration factor can be used in place of a calibration curve.

7.4 Internal standard calibration procedure--To use this approach, the analyst must select one or more internal standards that are similar in analytical behavior to the compounds of interest. The analyst must further demonstrate that the measurement of the internal standard is not affected by method or matrix interferences. Because of these limitations, no internal standard can be suggested that is applicable to all samples. The compounds recommended for use as surrogate spikes in Section 8.7 have been used successfully as internal standards, because of their generally unique retention times.

7.4.1 Prepare calibration standards at a minimum of three concentration levels for each parameter of interest as described in Section 7.3.1.

7.4.2 Prepare a spiking solution containing each of the internal standards using the procedures described in Sections 6.5 and 6.6. It is recommended that the secondary dilution standard be prepared at a concentration of 15 [micro]g/mL of each internal standard compound. The addition of 10 [micro]L of this standard to 5.0 mL of sample or calibration standard would be equivalent to 30 [micro]g/L.

Equation 1where: As=Response for the parameter to be measured.Ais=Response for the internal standard.Cis=Concentration of the internal standard.Cs=Concentration of the parameter to be measured. If the RF value over the working range is a constant (<10% RSD), the RF can be assumed to be invariant and the average RF can be used for calculations. Alternatively, the results can be used to plot a calibration curve of response ratios, As/Ais, vs. RF.

7.5 The working calibration curve, calibration factor, or RF must be verified on each working day by the measurement of a QC check sample.

7.5.1 Prepare the QC check sample as described in Section 8.2.2.

7.5.2 Analyze the QC check sample according to Section 10.

7.5.3 For each parameter, compare the response (Q) with the corresponding calibration acceptance criteria found in Table 2. If the responses for all parameters of interest fall within the designated ranges, analysis of actual samples can begin. If any individual Q falls outside the range, proceed according to Section 7.5.4.

Note: The large number of parameters in Table 2 present a substantial probability that one or more will not meet the calibration acceptance criteria when all parameters are analyzed.

7.5.4 Repeat the test only for those parameters that failed to meet the calibration acceptance criteria. If the response for a parameter does not fall within the range in this second test, a new calibration curve, calibration factor, or RF must be prepared for that parameter according to Section 7.3 or 7.4.

8. Quality Control

8.1 Each laboratory that uses this method is required to operate a formal quality control program. The minimum requirements of this program consist of an initial demonstration of laboratory capability and an ongoing analysis of spiked samples to evaluate and document data quality. The laboratory must maintain records to document the quality of data that is generated. Ongoing data quality checks are compared with established performance criteria to determine if the results of analyses meet the performance characteristics of the method. When results of sample spikes indicate atypical method performance, a quality control check standard must be analyzed to confirm that the measurements were performed in an in-control mode of operation.

8.1.1 The analyst must make an initial, one-time, demonstration of the ability to generate acceptable accuracy and precision with this method. This ability is established as described in Section 8.2.

8.1.2 In recognition of advances that are occurring in chromatography, the analyst is permitted certain options (detailed in Section 10.1) to improve the separations or lower the cost of measurements. Each time such a modification is made to the method, the analyst is required to repeat the procedure in Section 8.2.

8.1.3 Each day, the analyst must analyze a reagent water blank to demonstrate that interferences from the analytical system are under control.

8.1.4 The laboratory must, on an ongoing basis, spike and analyze a minimum of 10% of all samples to monitor and evaluate laboratory data quality. This procedure is described in Section 8.3.

8.1.5 The laboratory must, on an ongoing basis, demonstrate through the analyses of quality control check standards that the operation of the measurement system is in control. This procedure is described in Section 8.4. The frequency of the check standard analyses is equivalent to 10% of all samples analyzed but may be reduced if spike recoveries from samples (Section 8.3) meet all specified quality control criteria.

8.1.6 The laboratory must maintain performance records to document the quality of data that is generated. This procedure is described in Section 8.5.

8.2 To establish the ability to generate acceptable accuracy and precision, the analyst must perform the following operations.

8.2.1 A quality control (QC) check sample concentrate is required containing each parameter of interest at a concentration of 10 [micro]g/mL in methanol. The QC check sample concentrate must be obtained from the U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory in Cincinnati, Ohio, if available. If not available from that source, the QC check sample concentrate must be obtained from another external source. If not available from either source above, the QC check sample concentrate must be prepared by the laboratory using stock standards prepared independently from those used for calibration.

8.2.2 Prepare a QC check sample to contain 20 [micro]g/L of each parameter by adding 200 [micro]L of QC check sample concentrate to 100 mL of reagent water.

8.2.3 Analyze four 5-mL aliquots of the well-mixed QC check sample according to Section 10.

8.2.4 Calculate the average recovery (X) in [micro]g/L, and the standard deviation of the recovery (s) in [micro]g/L, for each parameter of interest using the four results.

8.2.5 For each parameter compare s and X with the corresponding acceptance criteria for precision and accuracy, respectively, found in Table 2. If s and X for all parameters of interest meet the acceptance criteria, the system performance is acceptable and analysis of actual samples can begin. If any individual s exceeds the precision limit or any individual X falls outside the range for accuracy, then the system performance is unacceptable for that parameter.

Note: The large number of parameters in Table 2 present a substantial probability that one or more will fail at least one of the acceptance criteria when all parameters are analyzed.

8.2.6 When one or more of the parameters tested fail at least one of the acceptance criteria, the analyst must proceed according to Section 8.2.6.1 or 8.2.6.2.

8.2.6.1 Locate and correct the source of the problem and repeat the test for all parameters of interest beginning with Section 8.2.3.

8.2.6.2 Beginning with Section 8.2.3, repeat the test only for those parameters that failed to meet criteria. Repeated failure, however, will confirm a general problem with the measurement system. If this occurs, locate and correct the source of the problem and repeat the test for all compounds of interest beginning with Section 8.2.3.

8.3 The laboratory must, on an ongoing basis, spike at least 10% of the samples from each sample site being monitored to assess accuracy. For laboratories analyzing one to ten samples per month, at least one spiked sample per month is required.

8.3.1 The concentration of the spike in the sample should be determined as follows:

8.3.1.1 If, as in compliance monitoring, the concentration of a specific parameter in the sample is being checked against a regulatory concentration limit, the spike should be at that limit or 1 to 5 times higher than the background concentration determined in Section 8.3.2, whichever concentration would be larger.

8.3.1.2 If the concentration of a specific parameter in the sample is not being checked against a limit specific to that parameter, the spike should be at 20 [micro]g/L or 1 to 5 times higher than the background concentration determined in Section 8.3.2, whichever concentration would be larger.

8.3.2 Analyze one 5-mL sample aliquot to determine the background concentration (B) of each parameter. If necessary, prepare a new QC check sample concentrate (Section 8.2.1) appropriate for the background concentrations in the sample. Spike a second 5-mL sample aliquot with 10 [micro]L of the QC check sample concentrate and analyze it to determine the concentration after spiking (A) of each parameter. Calculate each percent recovery (P) as 100(A-B)%/T, where T is the known true value of the spike.

8.3.3 Compare the percent recovery (P) for each parameter with the corresponding QC acceptance criteria found in Table 2. These acceptance criteria were calculated to include an allowance for error in measurement of both the background and spike concentrations, assuming a spike to background ratio of 5:1. This error will be accounted for to the extent that the analyst's spike to background ratio approaches 5:1. \7\ If spiking was performed at a concentration lower than 20 [micro]g/L, the analyst must use either the QC acceptance criteria in Table 2, or optional QC acceptance criteria calculated for the specific spike concentration. To calculate optional acceptance criteria for the recovery of a parameter: (1) Calculate accuracy (X') using the equation in Table 3, substituting the spike concentration (T) for C; (2) calculate overall precision (S') using the equation in Table 3, substituting X' for X; (3) calculate the range for recovery at the spike concentration as (100 X'/T)2.44(100 S'/T)%. \7\

8.3.4 If any individual P falls outside the designated range for recovery, that parameter has failed the acceptance criteria. A check standard containing each parameter that failed the criteria must be analyzed as described in Section 8.4.

8.4 If any parameter fails the acceptance criteria for recovery in Section 8.3, a QC check standard containing each parameter that failed must be prepared and analyzed.

Note: The frequency for the required analysis of a QC check standard will depend upon the number of parameters being simultaneously tested, the complexity of the sample matrix, and the performance of the laboratory. If the entire list of parameters in Table 2 must be measured in the sample in Section 8.3, the probability that the analysis of a QC check standard will be required is high. In this case the QC check standard should be routinely analyzed with the spiked sample.

8.4.1 Prepare the QC check standard by adding 10 [micro]L of QC check sample concentrate (Section 8.2.1 or 8.3.2) to 5 mL of reagent water. The QC check standard needs only to contain the parameters that failed criteria in the test in Section 8.3.

8.4.2 Analyze the QC check standard to determine the concentration measured (A) of each parameter. Calculate each percent recovery (Ps) as 100 (A/T)%, where T is the true value of the standard concentration.

8.4.3 Compare the percent recovery (Ps) for each parameter with the corresponding QC acceptance criteria found in Table 2. Only parameters that failed the test in Section 8.3 need to be compared with these criteria. If the recovery of any such parameter falls outside the designated range, the laboratory performance for that parameter is judged to be out of control, and the problem must be immediately identified and corrected. The analytical result for that parameter in the unspiked sample is suspect and may not be reported for regulatory compliance purposes.

8.5 As part of the QC program for the laboratory, method accuracy for wastewater samples must be assessed and records must be maintained. After the analysis of five spiked wastewater samples as in Section 8.3, calculate the average percent recovery (P) and the standard deviation of the percent recovery (sp). Express the accuracy assessment as a percent recovery interval from P-2sp to P+2sp. If p=90% and sp=10%, for example, the accuracy interval is expressed as 70-110%. Update the accuracy assessment for each parameter on a regular basis (e.g. after each five to ten new accuracy measurements).

8.6 It is recommended that the laboratory adopt additional quality assurance practices for use with this method. The specific practices that are most productive depend upon the needs of the laboratory and the nature of the samples. Field duplicates may be analyzed to assess the precision of the environmental measurements. When doubt exists over the identification of a peak on the chromatogram, confirmatory techniques such as gas chromatography with a dissimilar column, specific element detector, or mass spectrometer must be used. Whenever possible, the laboratory should analyze standard reference materials and participate in relevant performance evaluation studies.

8.7 The analyst should monitor both the performance of the analytical system and the effectiveness of the method in dealing with each sample matrix by spiking each sample, standard, and reagent water blank with surrogate halocarbons. A combination of bromochloromethane, 2-bromo-1-chloropropane, and 1,4-dichlorobutane is recommended to encompass the range of the temperature program used in this method. From stock standard solutions prepared as in Section 6.5, add a volume to give 750 [micro]g of each surrogate to 45 mL of reagent water contained in a 50-mL volumetric flask, mix and dilute to volume for a concentration of 15 ng/[micro]L. Add 10 [micro]L of this surrogate spiking solution directly into the 5-mL syringe with every sample and reference standard analyzed. Prepare a fresh surrogate spiking solution on a weekly basis. If the internal standard calibration procedure is being used, the surrogate compounds may be added directly to the internal standard spiking solution (Section 7.4.2).

9. Sample Collection, Preservation, and Handling

9.1 All samples must be iced or refrigerated from the time of collection until analysis. If the sample contains free or combined chlorine, add sodium thiosulfate preservative (10 mg/40 mL is sufficient for up to 5 ppm Cl2) to the empty sample bottle just prior to shipping to the sampling site. EPA Methods 330.4 and 330.5 may be used for measurement of residual chlorine. \8\ Field test kits are available for this purpose.

9.2 Grab samples must be collected in glass containers having a total volume of at least 25 mL. Fill the sample bottle just to overflowing in such a manner that no air bubbles pass through the sample as the bottle is being filled. Seal the bottle so that no air bubbles are entrapped in it. If preservative has been added, shake vigorously for 1 min. Maintain the hermetic seal on the sample bottle until time of analysis.

9.3 All samples must be analyzed within 14 days of collection. \3\

10. Procedure

10.1 Table 1 summarizes the recommended operating conditions for the gas chromatograph. Included in this table are estimated retention times and MDL that can be achieved under these conditions. An example of the separations achieved by Column 1 is shown in Figure 5. Other packed columns, chromatographic conditions, or detectors may be used if the requirements of Section 8.2 are met.

10.2 Calibrate the system daily as described in Section 7.

10.3 Adjust the purge gas (nitrogen or helium) flow rate to 40 mL/min. Attach the trap inlet to the purging device, and set the purge and trap system to purge (Figure 3). Open the syringe valve located on the purging device sample introduction needle.

10.4 Allow the sample to come to ambient temperature prior to introducing it to the syringe. Remove the plunger from a 5-mL syringe and attach a closed syringe valve. Open the sample bottle (or standard) and carefully pour the sample into the syringe barrel to just short of overflowing. Replace the syringe plunger and compress the sample. Open the syringe valve and vent any residual air while adjusting the sample volume to 5.0 mL. Since this process of taking an aliquot destroys the validity of the sample for future analysis, the analyst should fill a second syringe at this time to protect against possible loss of data. Add 10.0 [micro]L of the surrogate spiking solution (Section 8.7) and 10.0 [micro]L of the internal standard spiking solution (Section 7.4.2), if applicable, through the valve bore, then close the valve.

10.5 Attach the syringe-syringe valve assembly to the syringe valve on the purging device. Open the syringe valves and inject the sample into the purging chamber.

10.6 Close both valves and purge the sample for 11.0 0.1 min at ambient temperature.

10.7 After the 11-min purge time, attach the trap to the chromatograph, adjust the purge and trap system to the desorb mode (Figure 4), and begin to temperature program the gas chromatograph. Introduce the trapped materials to the GC column by rapidly heating the trap to 180 [deg]C while backflushing the trap with an inert gas between 20 and 60 mL/min for 4 min. If rapid heating of the trap cannot be achieved, the GC column must be used as a secondary trap by cooling it to 30 [deg]C (subambient temperature, if poor peak geometry or random retention time problems persist) instead of the initial program temperature of 45 [deg]C

10.8 While the trap is being desorbed into the gas chromatograph, empty the purging chamber using the sample introduction syringe. Wash the chamber with two 5-mL flushes of reagent water.

10.9 After desorbing the sample for 4 min, recondition the trap by returning the purge and trap system to the purge mode. Wait 15 s then close the syringe valve on the purging device to begin gas flow through the trap. The trap temperature should be maintained at 180 [deg]C After approximately 7 min, turn off the trap heater and open the syringe valve to stop the gas flow through the trap. When the trap is cool, the next sample can be analyzed.

10.10 Identify the parameters in the sample by comparing the retention times of the peaks in the sample chromatogram with those of the peaks in standard chromatograms. The width of the retention time window used to make identifications should be based upon measurements of actual retention time variations of standards over the course of a day. Three times the standard deviation of a retention time for a compound can be used to calculate a suggested window size; however, the experience of the analyst should weigh heavily in the interpretation of chromatograms.

10.11 If the response for a peak exceeds the working range of the system, prepare a dilution of the sample with reagent water from the aliquot in the second syringe and reanalyze.

11. Calculations

11.1 Determine the concentration of individual compounds in the sample.

11.1.1 If the external standard calibration procedure is used, calculate the concentration of the parameter being measured from the peak response using the calibration curve or calibration factor determined in Section 7.3.2.

11.1.2 If the internal standard calibration procedure is used, calculate the concentration in the sample using the response factor (RF) determined in Section 7.4.3 and Equation 2.

Equation 2[GRAPHIC(S) NOT AVAILABLE IN TIFF FORMAT] where: As=Response for the parameter to be measured.Ais=Response for the internal standard.Cis=Concentration of the internal standard.

11.2 Report results in [micro]g/L without correction for recovery data. All QC data obtained should be reported with the sample results.

12. Method Performance

12.1 The method detection limit (MDL) is defined as the minimum concentration of a substance that can be measured and reported with 99% confidence that the value is above zero. \1\ The MDL concentration listed in Table 1 were obtained using reagent water. \11\. Similar results were achieved using representative wastewaters. The MDL actually achieved in a given analysis will vary depending on instrument sensitivity and matrix effects.

12.2 This method is recommended for use in the concentration range from the MDL to 1000xMDL. Direct aqueous injection techniques should be used to measure concentration levels above 1000xMDL.

12.3 This method was tested by 20 laboratories using reagent water, drinking water, surface water, and three industrial wastewaters spiked at six concentrations over the range 8.0 to 500 [micro]g/L. \9\ Single operator precision, overall precision, and method accuracy were found to be directly related to the concentration of the parameter and essentially independent of the sample matrix. Linear equations to describe these relationships are presented in Table 3.

References

1. 40 CFR part 136, appendix B.

2. Bellar, T.A., and Lichtenberg, J.J. ``Determining Volatile Organics at Microgram-per-Litre-Levels by Gas Chromatography,'' Journal of the American Water Works Association, 66, 739 (1974).

3. Bellar, T.A., and Lichtenberg, J.J. ``Semi-Automated Headspace Analysis of Drinking Waters and Industrial Waters for Purgeable Volatile Organic Compounds,'' Proceedings from Symposium on Measurement of Organic Pollutants in Water and Wastewater, American Society for Testing and Materials, STP 686, C.E. Van Hall, editor, 1978.

4. ``Carcinogens--Working With Carcinogens,'' Department of Health, Education, and Welfare, Public Health Service, Center for Disease Control, National Institute for Occupational Safety and Health, Publication No. 77-206, August 1977.

5. ``OSHA Safety and Health Standards, General Industry'' (29 CFR part 1910), Occupational Safety and Health Administration, OSHA 2206 (Revised, January 1976).

6. ``Safety in Academic Chemistry Laboratories,'' American Chemical Society Publication, Committee on Chemical Safety, 3rd Edition, 1979.

7. Provost, L.P., and Elder, R.S. ``Interpretation of Percent Recovery Data,'' American Laboratory, 15, 58-63 (1983). (The value 2.44 used in the equation in Section 8.3.3 is two times the value 1.22 derived in this report.)

8. ``Methods 330.4 (Titrimetric, DPD-FAS) and 330.5 (Spectrophotometric, DPD) for Chlorine, Total Residual,'' Methods for Chemical Analysis of Water and Wastes, EPA 600/4-79-020, U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory, Cincinnati, Ohio 45268, March 1979.

9. ``EPA Method Study 24, Method 601--Purgeable Halocarbons by the Purge and Trap Method,'' EPA 600/4-84-064, National Technical Information Service, PB84-212448, Springfield, Virginia 22161, July 1984.

10. ``Method Validation Data for EPA Method 601,'' Memorandum from B. Potter, U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory, Cincinnati, Ohio 45268, November 10, 1983.

11. Bellar, T. A., Unpublished data, U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory, Cincinnati, Ohio 45268, 1981.

Table 1--Chromatographic Conditions and Method Detection Limits----------------------------------------------------------------------------------------------------------------

Retention time (min) Method detection

Parameter ------------------------------------ limit ([micro]g/

Column 1 Column 2 L)----------------------------------------------------------------------------------------------------------------Chloromethane............................................. 1.50 5.28 0.08Bromomethane.............................................. 2.17 7.05 1.18Dichlorodifluoromethane................................... 2.62 nd 1.81Vinyl chloride............................................ 2.67 5.28 0.18Chloroethane.............................................. 3.33 8.68 0.52Methylene chloride........................................ 5.25 10.1 0.25Trichlorofluoromethane.................................... 7.18 nd nd1,1-Dichloroethene........................................ 7.93 7.72 0.131,1-Dichloroethane........................................ 9.30 12.6 0.07trans-1,2-Dichloroethene.................................. 10.1 9.38 0.10Chloroform................................................ 10.7 12.1 0.051,2-Dichloroethane........................................ 11.4 15.4 0.031,1,1-Trichloroethane..................................... 12.6 13.1 0.03Carbon tetrachloride...................................... 13.0 14.4 0.12Bromodichloromethane...................................... 13.7 14.6 0.101,2-Dichloropropane....................................... 14.9 16.6 0.04cis-1,3-Dichloropropene................................... 15.2 16.6 0.34Trichloroethene........................................... 15.8 13.1 0.12Dibromochloromethane...................................... 16.5 16.6 0.091,1,2-Trichloroethane..................................... 16.5 18.1 0.02trans-1,3-Dichloropropene................................. 16.5 18.0 0.202-Chloroethylvinyl ether.................................. 18.0 nd 0.13Bromoform................................................. 19.2 19.2 0.201,1,2,2-Tetrachloroethane................................. 21.6 nd 0.03Tetrachloroethene......................................... 21.7 15.0 0.03Chlorobenzene............................................. 24.2 18.8 0.251,3-Dichlorobenzene....................................... 34.0 22.4 0.321,2-Dichlorobenzene....................................... 34.9 23.5 0.151,4-Dichlorobenzene....................................... 35.4 22.3 0.24----------------------------------------------------------------------------------------------------------------Column 1 conditions: Carbopack B (60/80 mesh) coated with 1% SP-1000 packed in an 8 ft x 0.1 in. ID stainless

steel or glass column with helium carrier gas at 40 mL/min flow rate. Column temperature held at 45 [deg]C for

3 min then programmed at 8 [deg]C/min to 220 [deg]C and held for 15 min.Column 2 conditions: Porisil-C (100/120 mesh) coated with n-octane packed in a 6 ft x 0.1 in. ID stainless steel

or glass column with helium carrier gas at 40 mL/min flow rate. Column temperature held at 50 [deg]C for 3 min

then programmed at 6 [deg]C/min to 170 [deg]C and held for 4 min.nd=not determined.

Table 2--Calibration and QC Acceptance Criteria--Method 601 \a\----------------------------------------------------------------------------------------------------------------

Limit for

Range for Q s Range for X Range P,

Parameter ([micro]g/L) ([micro]g/ ([micro]g/L) Ps (%)

L)----------------------------------------------------------------------------------------------------------------Bromodichloromethane.................................... 15.2-24.8 4.3 10.7-32.0 42-172Bromoform............................................... 14.7-25.3 4.7 5.0-29.3 13-159Bromomethane............................................ 11.7-28.3 7.6 3.4-24.5 D-144Carbon tetrachloride.................................... 13.7-26.3 5.6 11.8-25.3 43-143Chlorobenzene........................................... 14.4-25.6 5.0 10.2-27.4 38-150Chloroethane............................................ 15.4-24.6 4.4 11.3-25.2 46-1372-Chloroethylvinyl ether................................ 12.0-28.0 8.3 4.5-35.5 14-186Chloroform.............................................. 15.0-25.0 4.5 12.4-24.0 49-133Chloromethane........................................... 11.9-28.1 7.4 D-34.9 D-193Dibromochloromethane.................................... 13.1-26.9 6.3 7.9-35.1 24-1911,2-Dichlorobenzene..................................... 14.0-26.0 5.5 1.7-38.9 D-2081,3-Dichlorobenzene..................................... 9.9-30.1 9.1 6.2-32.6 7-1871,4-Dichlorobenzene..................................... 13.9-26.1 5.5 11.5-25.5 42-1431,1-Dichloroethane...................................... 16.8-23.2 3.2 11.2-24.6 47-1321,2-Dichloroethane...................................... 14.3-25.7 5.2 13.0-26.5 51-1471,1-Dichloroethene...................................... 12.6-27.4 6.6 10.2-27.3 28-167trans-1,2-Dichloroethene................................ 12.8-27.2 6.4 11.4-27.1 38-1551,2-Dichloropropane..................................... 14.8-25.2 5.2 10.1-29.9 44-156cis-1,3-Dichloropropene................................. 12.8-27.2 7.3 6.2-33.8 22-178trans-1,3-Dichloropropene............................... 12.8-27.2 7.3 6.2-33.8 22-178Methylene chloride...................................... 15.5-24.5 4.0 7.0-27.6 25-1621,1,2,2-Tetrachloroethane............................... 9.8-30.2 9.2 6.6-31.8 8-184Tetrachloroethene....................................... 14.0-26.0 5.4 8.1-29.6 26-162

1,1,1-Trichloroethane................................... 14.2-25.8 4.9 10.8-24.8 41-1381,1,2-Trichloroethane................................... 15.7-24.3 3.9 9.6-25.4 39-136Trichloroethene......................................... 15.4-24.6 4.2 9.2-26.6 35-146Trichlorofluoromethane.................................. 13.3-26.7 6.0 7.4-28.1 21-156Vinyl chloride.......................................... 13.7-26.3 5.7 8.2-29.9 28-163----------------------------------------------------------------------------------------------------------------\a\ Criteria were calculated assuming a QC check sample concentration of 20 [micro]g/L.Q=Concentration measured in QC check sample, in [micro]g/L (Section 7.5.3).s=Standard deviation of four recovery measurements, in [micro]g/L (Section 8.2.4).X=Average recovery for four recovery measurements, in [micro]g/L (Section 8.2.4).P, Ps=Percent recovery measured (Section 8.3.2, Section 8.4.2).D=Detected; result must be greater than zero.

Note: These criteria are based directly upon the method performance data in Table 3. Where necessary, the limits

for recovery have been broadened to assure applicability of the limits to concentrations below those used to

develop Table 3.

Table 3--Method Accuracy and Precision as Functions of Concentration--Method 601----------------------------------------------------------------------------------------------------------------

Single analyst

Parameter Accuracy, as recovery, precision, sr' Overall precision, S'

X' ([micro]g/L) ([micro]g/L) ([micro]g/L)----------------------------------------------------------------------------------------------------------------Bromodichloromethane................ 1.12C-1.02 0.11X+0.04 0.20X+1.00Bromoform........................... 0.96C-2.05 0.12X+0.58 0.21X+2.41Bromomethane........................ 0.76C-1.27 0.28X+0.27 0.36X+0.94Carbon tetrachloride................ 0.98C-1.04 0.15X+0.38 0.20X+0.39Chlorobenzene....................... 1.00C-1.23 0.15X-0.02 0.18X+1.21Choroethane......................... 0.99C-1.53 0.14X-0.13 0.17X+0.632-Chloroethylvinyl ether \a\........ 1.00C 0.20X 0.35XChloroform.......................... 0.93C-0.39 0.13X+0.15 0.19X-0.02Chloromethane....................... 0.77C+0.18 0.28X-0.31 0.52X+1.31Dibromochloromethane................ 0.94C+2.72 0.11X+1.10 0.24X+1.681,2-Dichlorobenzene................. 0.93C+1.70 0.20X+0.97 0.13X+6.131,3-Dichlorobenzene................. 0.95C+0.43 0.14X+2.33 0.26X+2.341,4-Dichlorobenzene................. 0.93C-0.09 0.15X+0.29 0.20X+0.411,1-Dichloroethane.................. 0.95C-1.08 0.09X+0.17 0.14X+0.941,2-Dichloroethane.................. 1.04C-1.06 0.11X+0.70 0.15X+0.941,1-Dichloroethene.................. 0.98C-0.87 0.21X-0.23 0.29X-0.40trans-1,2-Dichloroethene............ 0.97C-0.16 0.11X+1.46 0.17X+1.461,2-Dichloropropane \a\............. 1.00C 0.13X 0.23Xcis-1,3-Dichloropropene \a\......... 1.00C 0.18X 0.32Xtrans-1,3-Dichloropropene \a\....... 1.00C 0.18X 0.32XMethylene chloride.................. 0.91C-0.93 0.11X+0.33 0.21X+1.431,1,2,2-Tetrachloroethene........... 0.95C+0.19 0.14X+2.41 0.23X+2.79Tetrachloroethene................... 0.94C+0.06 0.14X+0.38 0.18X+2.211,1,1-Trichloroethane............... 0.90C-0.16 0.15X+0.04 0.20X+0.371,1,2-Trichloroethane............... 0.86C+0.30 0.13X-0.14 0.19X+0.67Trichloroethene..................... 0.87C+0.48 0.13X-0.03 0.23X+0.30Trichlorofluoromethane.............. 0.89C-0.07 0.15X+0.67 0.26X+0.91Vinyl chloride...................... 0.97C-0.36 0.13X+0.65 0.27X+0.40----------------------------------------------------------------------------------------------------------------X'=Expected recovery for one or more measurements of a sample containing a concentration of C, in [micro]g/L.sn'=Expected single analyst standard deviation of measurements at an average concentration found of X, in

[micro]g/L.S\1\=Expected interlaboratory standard deviation of measurements at an average concentration found of X, in

[micro]g/L.C=True value for the concentration, in [micro]g/L.X=Average recovery found for measurements of samples containing a concentration of C, in [micro]g/L.\a\ Estimates based upon the performance in a single laboratory. \10\ [GRAPHIC(S) NOT AVAILABLE IN TIFF FORMAT] [GRAPHIC(S) NOT AVAILABLE IN TIFF FORMAT] [GRAPHIC(S) NOT AVAILABLE IN TIFF FORMAT] [GRAPHIC(S) NOT AVAILABLE IN TIFF FORMAT]

Method 602--Purgeable Aromatics

1. Scope and Application

1.1 This method covers the determination of various purgeable aromatics. The following parameters may be determined by this method: ------------------------------------------------------------------------

STORET

2. Summary of Method

2.1 An inert gas is bubbled through a 5-mL water sample contained in a specially-designed purging chamber at ambient temperature. The aromatics are efficiently transferred from the aqueous phase to the vapor phase. The vapor is swept through a sorbent trap where the aromatics are trapped. After purging is completed, the trap is heated and backflushed with the inert gas to desorb the aromatics onto a gas chromatographic column. The gas chromatograph is temperature programmed to separate the aromatics which are then detected with a photoionization detector. \2 3\

2.2 The method provides an optional gas chromatographic column that may be helpful in resolving the compounds of interest from interferences that may occur.

3. Interferences

3.2 Samples can be contaminated by diffusion of volatile organics through the septum seal into the sample during shipment and storage. A field reagent blank prepared from reagent water and carried through the sampling and handling protocol can serve as a check on such contamination.

3.3 Contamination by carry-over can occur whenever high level and low level samples are sequentially analyzed. To reduce carry-over, the purging device and sample syringe must be rinsed with reagent water between sample analyses. Whenever an unusually concentrated sample is encountered, it should be followed by an analysis of reagent water to check for cross contamination. For samples containing large amounts of water-soluble materials, suspended solids, high boiling compounds or high aromatic levels, it may be necessary to wash the purging device with a detergent solution, rinse it with distilled water, and then dry it in an oven at 105 [deg]C between analyses. The trap and other parts of the system are also subject to contamination; therefore, frequent bakeout and purging of the entire system may be required.

4. Safety

4.2 The following parameters covered by this method have been tentatively classified as known or suspected, human or mammalian carcinogens: benzene and 1,4-dichlorobenzene. Primary standards of these toxic compounds should be prepared in a hood. A NIOSH/MESA approved toxic gas respirator should be worn when the analyst handles high concentrations of these toxic compounds.

5. Apparatus and Materials

5.1 Sampling equipment, for discrete sampling.

5.1.1 Vial]25-mL capacity or larger, equipped with a screw cap with a hole in the center (Pierce 13075 or equivalent). Detergent wash, rinse with tap and distilled water, and dry at 105 [deg]C before use.

5.1.2 Septum--Teflon-faced silicone (Pierce 12722 or equivalent). Detergent wash, rinse with tap and distilled water, and dry at 105 [deg]C for 1 h before use.

5.2 Purge and trap system--The purge and trap system consists of three separate pieces of equipment: A purging device, trap, and desorber. Several complete systems are now commercially available.

5.2.2 The trap must be at least 25 cm long and have an inside diameter of at least 0.105 in.

5.2.2.1 The trap is packed with 1 cm of methyl silicone coated packing (Section 6.4.2) and 23 cm of 2,6-diphenylene oxide polymer (Section 6.4.1) as shown in Figure 2. This trap was used to develop the method performance statements in Section 12.

5.2.2.2 Alternatively, either of the two traps described in Method 601 may be used, although water vapor will preclude the measurement of low concentrations of benzene.

5.2.4 The purge and trap system may be assembled as a separate unit or be coupled to a gas chromatograph as illustrated in Figures 3, 4, and 5.

5.3.1 Column 1--6 ft long x 0.082 in. ID stainless steel or glass, packed with 5% SP-1200 and 1.75% Bentone-34 on Supelcoport (100/120 mesh) or equivalent. This column was used to develop the method performance statements in Section 12. Guidelines for the use of alternate column packings are provided in Section 10.1.

5.3.2 Column 2--8 ft long x 0.1 in ID stainless steel or glass, packed with 5% 1,2,3-Tris(2-cyanoethoxy)propane on Chromosorb W-AW (60/80 mesh) or equivalent.

5.3.3 Detector--Photoionization detector (h-Nu Systems, Inc. Model PI-51-02 or equivalent). This type of detector has been proven effective in the analysis of wastewaters for the parameters listed in the scope (Section 1.1), and was used to develop the method performance statements in Section 12. Guidelines for the use of alternate detectors are provided in Section 10.1.

5.4 Syringes--5-mL glass hypodermic with Luerlok tip (two each), if applicable to the purging device.

5.5 Micro syringes--25-[micro]L, 0.006 in. ID needle.

5.6 Syringe valve--2-way, with Luer ends (three each).

5.7 Bottle--15-mL, screw-cap, with Teflon cap liner.

5.8 Balance--Analytical, capable of accurately weighing 0.0001 g.

6. Reagents

6.1 Reagent water--Reagent water is defined as a water in which an interferent is not observed at the MDL of the parameters of interest.

6.1.1 Reagent water can be generated by passing tap water through a carbon filter bed containing about 1 lb of activated carbon (Filtrasorb-300, Calgon Corp., or equivalent).

6.1.2 A water purification system (Millipore Super-Q or equivalent) may be used to generate reagent water.

6.2 Sodium thiosulfate--(ACS) Granular.

6.3 Hydrochloric acid (1+1)--Add 50 mL of concentrated HCl (ACS) to 50 mL of reagent water.

6.4 Trap Materials:

6.4.1 2,6-Diphenylene oxide polymer--Tenax, (60/80 mesh), chromatographic grade or equivalent.

6.4.2 Methyl silicone packing--3% OV-1 on Chromosorb-W (60/80 mesh) or equivalent.

6.5 Methanol--Pesticide quality or equivalent.

6.6 Stock standard solutions--Stock standard solutions may be prepared from pure standard materials or purchased as certified solutions. Prepare stock standard solutions in methanol using assayed liquids. Because of the toxicity of benzene and 1,4-dichlorobenzene, primary dilutions of these materials should be prepared in a hood. A NIOSH/MESA approved toxic gas respirator should be used when the analyst handles high concentrations of such materials.

6.6.1 Place about 9.8 mL of methanol into a 10-mL ground glass stoppered volumetric flask. Allow the flask to stand, unstoppered, for about 10 min or until all alcohol wetted surfaces have dried. Weigh the flask to the nearest 0.1 mg.

6.6.2 Using a 100-[micro]L syringe, immediately add two or more drops of assayed reference material to the flask, then reweigh. Be sure that the drops fall directly into the alcohol without contacting the neck of the flask.

6.6.4 Transfer the stock standard solution into a Teflon-sealed screw-cap bottle. Store at 4 [deg]C and protect from light.

6.6.5 All standards must be replaced after one month, or sooner if comparison with check standards indicates a problem.

6.7 Secondary dilution standards--Using stock standard solutions, prepare secondary dilution standards in methanol that contain the compounds of interest, either singly or mixed together. The secondary dilution standards should be prepared at concentrations such that the aqueous calibration standards prepared in Section 7.3.1 or 7.4.1 will bracket the working range of the analytical system. Secondary solution standards must be stored with zero headspace and should be checked frequently for signs of degradation or evaporation, especially just prior to preparing calibration standards from them.

6.8 Quality control check sample concentrate--See Section 8.2.1.

7. Calibration

7.3 External standard calibration procedure:

7.3.1 Prepare calibration standards at a minimum of three concentration levels for each parameter by carefully adding 20.0 [micro]L of one or more secondary dilution standards to 100, 500, or 1000 mL of reagent water. A 25-[micro]L syringe with a 0.006 in. ID needle should be used for this operation. One of the external standards should be at a concentration near, but above, the MDL (Table 1) and the other concentrations should correspond to the expected range of concentrations found in real samples or should define the working range of the detector. These aqueous standards must be prepared fresh daily.

7.4 Internal standard calibration procedure--To use this approach, the analyst must select one or more internal standards that are similar in analytical behavior to the compounds of interest. The analyst must further demonstrate that the measurement of the internal standard is not affected by method or matrix interferences. Because of these limitations, no internal standard can be suggested that is applicable to all samples. The compound, [alpha],[alpha],[alpha],-trifluorotoluene, recommended as a surrogate spiking compound in Section 8.7 has been used successfully as an internal standard.

7.4.1 Prepare calibration standards at a minimum of three concentration levels for each parameter of interest as described in Section 7.3.1.

7.4.2 Prepare a spiking solution containing each of the internal standards using the procedures described in Sections 6.6 and 6.7. It is recommended that the secondary dilution standard be prepared at a concentration of 15 [micro]g/mL of each internal standard compound. The addition of 10 [micro]l of this standard to 5.0 mL of sample or calibration standard would be equivalent to 30 [micro]g/L.

7.4.3 Analyze each calibration standard according to Section 10, adding 10 [micro]L of internal standard spiking solution directly to the syringe (Section 10.4). Tabulate peak height or area responses against concentration for each compound and internal standard, and calculate response factors (RF) for each compound using Equation 1. RF = (As)(Cis (Ais)(Cs) Equation 1 where:As=Response for the parameter to be measured.Ais=Response for the internal standard.Cis=Concentration of the internal standardCs=Concentration of the parameter to be measured. If the RF value over the working range is a constant (<10% RSD), the RF can be assumed to be invariant and the average RF can be used for calculations. Alternatively, the results can be used to plot a calibration curve of response ratios, As/Ais, vs. RF.

7.5 The working calibration curve, calibration factor, or RF must be verified on each working day by the measurement of a QC check sample.

7.5.1 Prepare the QC check sample as described in Section 8.2.2.

7.5.2 Analyze the QC check sample according to Section 10.

8. Quality Control

8.1 Each laboratory that uses this method is required to operate a formal quality control program. The mimimum requirements of this program consist of an initial demonstration of laboratory capability and an ongoing analysis of spiked samples to evaluate and document data quality. The laboratory must maintain records to document the quality of data that is generated. Ongoing data quality checks are compared with established performance criteria to determine if the results of analyses meet the performance characteristics of the method. When results of sample spikes indicate atypical method performance, a quality control check standard must be analyzed to confirm that the measurements were performed in an in-control mode of operation.

8.1.1 The analyst must make an initial, one-time, demonstration of the ability to generate acceptable accuracy and precision with this method. This ability is established as described in Section 8.2.

8.1.3 Each day, the analyst must analyze a reagent water blank to demonstrate that interferences from the analytical system are under control.

8.1.4 The laboratory must, on an ongoing basis, spike and analyze a minimum of 10% of all samples to monitor and evaluate laboratory data quality. This procedure is described in Section 8.3.

8.1.6 The laboratory must maintain performance records to document the quality of data that is generated. This procedure is described in Section 8.5.

8.2 To establish the ability to generate acceptable accuracy and precision, the analyst must perform the following operations.

8.2.2 Prepare a QC check sample to contain 20 [micro]g/L of each parameter by adding 200 [micro]L of QC check sample concentrate to 100 mL of reagant water.

8.2.3 Analyze four 5-mL aliquots of the well-mixed QC check sample according to Section 10.

8.2.4 Calculate the average recovery (X) in [micro]g/L, and the standard deviation of the recovery (s) in [micro]g/L, for each parameter of interest using the four results.

8.2.5 For each parameter compare s and X with the corresponding acceptance criteria for precision and accuracy, respectively, found in Table 2. If s and X for all parameters of interest meet the acceptance criteria, the system performance is acceptable and analysis of actual samples can begin. If any individual s exceeds the precision limit or any individual X falls outside the range for accuracy, the system performance is unacceptable for that parameter.

Note: The large number of parameters in Table 2 present a substantial probability that one or more will fail at least one of the acceptance criteria when all parameters are analyzed.

8.2.6 When one or more of the parameters tested fail at least one of the acceptance criteria, the analyst must proceed according to Section 8.2.6.1 or 8.2.6.2.

8.2.6.1 Locate and correct the source of the problem and repeat the test for all parameters of interest beginning with Section 8.2.3.

8.3.1 The concentration of the spike in the sample should be determined as follows:

8.4 If any parameter fails the acceptance criteria for recovery in Section 8.3, a QC check standard containing each parameter that failed must be prepared and analyzed.

8.5 As part of the QC program for the laboratory, method accuracy for wastewater samples must be assessed and records must be maintained. After the analysis of five spiked wastewater samples as in Section 8.3, calculate the average percent recovery (P) and the standard deviation of the percent recovery (sp). Express the accuracy assessment as a percent recovery interval from P-2sp to P+2sp. If P=90% and sp=10%, for example, the accuracy interval is expressed as 70-110%. Update the accuracy assessment for each parameter on a regular basis (e.g. after each five to ten new accuracy measurements).

8.7 The analyst should monitor both the performance of the analytical system and the effectiveness of the method in dealing with each sample matrix by spiking each sample, standard, and reagent water blank with surrogate compounds (e.g. [alpha], [alpha], [alpha],-trifluorotoluene) that encompass the range of the temperature program used in this method. From stock standard solutions prepared as in Section 6.6, add a volume to give 750 [micro]g of each surrogate to 45 mL of reagent water contained in a 50-mL volumetric flask, mix and dilute to volume for a concentration of 15 mg/[micro]L. Add 10 [micro]L of this surrogate spiking solution directly into the 5-mL syringe with every sample and reference standard analyzed. Prepare a fresh surrogate spiking solution on a weekly basis. If the internal standard calibration procedure is being used, the surrogate compounds may be added directly to the internal standard spiking solution (Section 7.4.2).

9. Sample Collection, Preservation, and Handling

9.1 The samples must be iced or refrigerated from the time of collection until analysis. If the sample contains free or combined chlorine, add sodium thiosulfate preservative (10 mg/40 mL is sufficient for up to 5 ppm Cl2) to the empty sample bottle just prior to shipping to the sampling site. EPA Method 330.4 or 330.5 may be used for measurement of residual chlorine. \8\ Field test kits are available for this purpose.

9.2 Collect about 500 mL of sample in a clean container. Adjust the pH of the sample to about 2 by adding 1+1 HCl while stirring. Fill the sample bottle in such a manner that no air bubbles pass through the sample as the bottle is being filled. Seal the bottle so that no air bubbles are entrapped in it. Maintain the hermetic seal on the sample bottle until time of analysis.

9.3 All samples must be analyzed within 14 days of collection. \3\

10. Procedure

10.1 Table 1 summarizes the recommended operating conditions for the gas chromatograph. Included in this table are estimated retention times and MDL that can be achieved under these conditions. An example of the separations achieved by Column 1 is shown in Figure 6. Other packed columns, chromatographic conditions, or detectors may be used if the requirements of Section 8.2 are met.

10.2 Calibrate the system daily as described in Section 7.

10.5 Attach the syringe-syringe valve assembly to the syringe valve on the purging device. Open the syringe valves and inject the sample into the purging chamber.

10.6 Close both valves and purge the sample for 12.0 0.1 min at ambient temperature.

10.7 After the 12-min purge time, disconnect the purging device from the trap. Dry the trap by maintaining a flow of 40 mL/min of dry purge gas through it for 6 min (Figure 4). If the purging device has no provision for bypassing the purger for this step, a dry purger should be inserted into the device to minimize moisture in the gas. Attach the trap to the chromatograph, adjust the purge and trap system to the desorb mode (Figure 5), and begin to temperature program the gas chromatograph. Introduce the trapped materials to the GC column by rapidly heating the trap to 180 [deg]C while backflushing the trap with an inert gas between 20 and 60 mL/min for 4 min. If rapid heating of the trap cannot be achieved, the GC column must be used as a secondary trap by cooling it to 30 [deg]C (subambient temperature, if poor peak geometry and random retention time problems persist) instead of the initial program temperature of 50 [deg]C.

10.8 While the trap is being desorbed into the gas chromatograph column, empty the purging chamber using the sample introduction syringe. Wash the chamber with two 5-mL flushes of reagent water.

10.9 After desorbing the sample for 4 min, recondition the trap by returning the purge and trap system to the purge mode. Wait 15 s, then close the syringe valve on the purging device to begin gas flow through the trap. The trap temperature should be maintained at 180 [deg]C. After approximately 7 min, turn off the trap heater and open the syringe valve to stop the gas flow through the trap. When the trap is cool, the next sample can be analyzed.

10.11 If the response for a peak exceeds the working range of the system, prepare a dilution of the sample with reagent water from the aliquot in the second syringe and reanalyze.

11. Calculations

11.1 Determine the concentration of individual compounds in the sample.

11.1.2 If the internal standard calibration procedure is used, calculate the concentration in the sample using the response factor (RF) determined in Section 7.4.3 and Equation 2. [GRAPHIC(S) NOT AVAILABLE IN TIFF FORMAT]

Equation 2where: As = Response for the parameter to be measured.Ais = Response for the internal standard.Cis = Concentration of the internal standard.

11.2 Report results in [micro]g/L without correction for recovery data. All QC data obtained should be reported with the sample results.

12. Method Performance

12.1 The method detection limit (MDL) is defined as the minimum concentration of a substance that can be measured and reported with 99% confidence that the value is above zero. \1\ The MDL concentrations listed in Table 1 were obtained using reagent water. \9\ Similar results were achieved using representative wastewaters. The MDL actually achieved in a given analysis will vary depending on instrument sensitivity and matrix effects.

12.2 This method has been demonstrated to be applicable for the concentration range from the MDL to 100 x MDL. \9\ Direct aqueous injection techniques should be used to measure concentration levels above 1000 x MDL.

12.3 This method was tested by 20 laboratories using reagent water, drinking water, surface water, and three industrial wastewaters spiked at six concentrations over the range 2.1 to 550 [micro]g/L. \9\ Single operator precision, overall precision, and method accuracy were found to be directly related to the concentration of the parameter and essentially independent of the sample matrix. Linear equations to describe these relationships are presented in Table 3.

References

1. 40 CFR part 136, appendix B.

2. Lichtenberg, J.J. ``Determining Volatile Organics at Microgram-per-Litre-Levels by Gas Chromatography,'' Journal American Water Works Association, 66, 739 (1974).

3. Bellar, T.A., and Lichtenberg, J.J. ``Semi-Automated Headspace Analysis of Drinking Waters and Industrial Waters for Purgeable Volatile Organic Compounds,'' Proceedings of Symposium on Measurement of Organic Pollutants in Water and Wastewater. American Society for Testing and Materials, STP 686, C.E. Van Hall, editor, 1978.

4. ``Carcinogens--Working with Carcinogens,'' Department of Health, Education, and Welfare, Public Health Service, Center for Disease Control, National Institute for Occupational Safety and Health. Publication No. 77-206, August 1977.

5. ``OSHA Safety and Health Standards, General Industry,'' (29 CFR part 1910), Occupational Safety and Health Administration, OSHA 2206 (Revised, January 1976).

6. ``Safety in Academic Chemistry Laboratories,'' American Chemical Society Publication, Committee on Safety, 3rd Edition, 1979.

7. Provost, L.P., and Elder, R.S. ``Interpretation of Percent Recovery Data,'' American Laboratory, 15, 58-63 (1983). (The value 2.44 used in the equation in Section 8.3.3. is two times the value 1.22 derived in this report.)

8.``Methods 330.4 (Titrimetric, DPD-FAS) and 330.5 (Spectrophotometric, DPD) for Chlorine, Total Residual,'' Methods for Chemical Analysis of Water and Wastes, EPA-600/4-79-020, U.S. Environmental Protection Agency, Office of Research and Development, Environmental Monitoring and Support Laboratory, Cincinnati, Ohio 45268. March 1979.

9. ``EPA Method Study 25, Method 602, Purgeable Aromatics,'' EPA 600/4-84-042, National Technical Information Service, PB84-196682, Springfield, Virginia 22161, May 1984.

Table 1--Chromatographic Conditions and Method Detection Limits------------------------------------------------------------------------

Retention time (min) Method

---------------------- detection

Parameter limit

Column 1 Column 2 ([micro]g/

L)------------------------------------------------------------------------Benzene............................... 3.33 2.75 0.2Toluene............................... 5.75 4.25 0.2Ethylbenzene.......................... 8.25 6.25 0.2Chlorobenzene......................... 9.17 8.02 0.21,4-Dichlorobenzene................... 16.8 16.2 0.31,3-Dichlorobenzene................... 18.2 15.0 0.41,2-Dichlorobenzene................... 25.9 19.4 0.4------------------------------------------------------------------------Column 1 conditions: Supelcoport (100/120 mesh) coated with 5% SP-1200/

1.75% Bentone-34 packed in a 6 ft x 0.085 in. ID stainless steel

column with helium carrier gas at 36 mL/min flow rate. Column

temperature held at 50 [deg]C for 2 min then programmed at 6 [deg]C/

min to 90 [deg]C for a final hold.Column 2 conditions: Chromosorb W-AW (60/80 mesh) coated with 5% 1,2,3-

Tris(2-cyanoethyoxy)propane packed in a 6 ft x 0.085 in. ID stainless

steel column with helium carrier gas at 30 mL/min flow rate. Column

temperature held at 40 [deg]C for 2 min then programmed at 2 [deg]C/

min to 100 [deg]C for a final hold.

Table 2--Calibration and QC Acceptance Criteria--Method 602 \a\----------------------------------------------------------------------------------------------------------------

Limit for

Range for Q s Range for X Range for

Parameter ([micro]g/ ([micro]g/ ([micro]g/ P, Ps(%)

L) L) L)----------------------------------------------------------------------------------------------------------------Benzene........................................................ 15.4-24.6 4.1 10.0-27.9 39-150Chlorobenzene.................................................. 16.1-23.9 3.5 12.7-25.4 55-1351,2-Dichlorobenzene............................................ 13.6-26.4 5.8 10.6-27.6 37-1541,3-Dichlorobenzene............................................ 14.5-25.5 5.0 12.8-25.5 50-1411,4-Dichlorobenzene............................................ 13.9-26.1 5.5 11.6-25.5 42-143Ethylbenzene................................................... 12.6-27.4 6.7 10.0-28.2 32-160Toluene........................................................ 15.5-24.5 4.0 11.2-27.7 46-148----------------------------------------------------------------------------------------------------------------Q=Concentration measured in QC check sample, in [micro]g/L (Section 7.5.3).s=Standard deviation of four recovery measurements, in [micro]g/L (Section 8.2.4).X=Average recovery for four recovery measurements, in [micro]g/L (Section 8.2.4).Ps, P=Percent recovery measured (Section 8.3.2, Section 8.4.2).\a\ Criteria were calculated assuming a QC check sample concentration of 20 [micro]g/L.

Note: These criteria are based directly upon the method performance data in Table 3. Where necessary, the limits

for recovery have been broadened to assure applicability of the limits to concentrations below those used to

develop Table 3.

Table 3--Method Accuracy and Precision as Functions of Concentration--Method 602----------------------------------------------------------------------------------------------------------------

Accuracy, as Single analyst Overall

Parameter recovery, X' precision, s' precision, S'

[micro]g/L.S'=Expected interlaboratory standard deviation of measurements at an average concentration found of X, in

[micro]g/L.C=True value for the Concentration, in [micro]g/L.X=Average recovery found for measurements of samples containing a concentration of C, in [micro]g/L. [GRAPHIC(S) NOT AVAILABLE IN TIFF FORMAT] [GRAPHIC(S) NOT AVAILABLE IN TIFF FORMAT] [GRAPHIC(S) NOT AVAILABLE IN TIFF FORMAT] [GRAPHIC(S) NOT AVAILABLE IN TIFF FORMAT]

Method 603--Acrolein and Acrylonitrile

1. Scope and Application

1.1 This method covers the determination of acrolein and acrylonitrile. The following parameters may be determined by this method: ------------------------------------------------------------------------

STORET

Parameter No. CAS No.------------------------------------------------------------------------Acrolein......................................... 34210 107-02-8Acrylonitrile.................................... 34215 107-13-1------------------------------------------------------------------------

1.2 This is a purge and trap gas chromatographic (GC) method applicable to the determination of the compounds listed above in municipal and industrial discharges as provided under 40 CFR 136.1. When this method is used to analyze unfamiliar samples for either or both of the compounds above, compound identifications should be supported by at least one additional qualitative technique. This method describes analytical conditions for a second gas chromatographic column that can be used to confirm measurements made with the primary column. Method 624 provides gas chromatograph/mass spectrometer (GC/MS) conditions appropriate for the qualitative and quantitative confirmation of results for the parameters listed above, if used with the purge and trap conditions described in this method.

2. Summary of Method

2.1 An inert gas is bubbled through a 5-mL water sample contained in a heated purging chamber. Acrolein and acrylonitrile are transferred from the aqueous phase to the vapor phase. The vapor is swept through a sorbent trap where the analytes are trapped. After the purge is completed, the trap is heated and backflushed with the inert gas to desorb the compound onto a gas chromatographic column. The gas chromatograph is temperature programmed to separate the analytes which are then detected with a flame ionization detector. \2 3\

2.2 The method provides an optional gas chromatographic column that may be helpful in resolving the compounds of interest from the interferences that may occur.

3. Interferences

3.1 Impurities in the purge gas and organic compound outgassing from the plumbing of the trap account for the majority of contamination problems. The analytical system must be demonstrated to be free from contamination under the conditions of the analysis by running laboratory reagent blanks as described in Section 8.1.3. The use of non-Teflon plastic tubing, non-Teflon thread sealants, or flow controllers with rubber components in the purge and trap system should be avoided.

3.3 Contamination by carry-over can occur whenever high level and low level samples are sequentially analyzed. To reduce carry-over, the purging device and sample syringe must be rinsed between samples with reagent water. Whenever an unusually concentrated sample is encountered, it should be followed by an analysis of reagent water to check for cross contamination. For samples containing large amounts of water-soluble materials, suspended solids, high boiling compounds or high analyte levels, it may be necessary to wash the purging device with a detergent solution, rinse it with distilled water, and then dry it in an oven at 105 [deg]C between analyses. The trap and other parts of the system are also subject to contamination, therefore, frequent bakeout and purging of the entire system may be required.

4. Safety

4.1 The toxicity or carcinogenicity of each reagent used in this method has not been precisely defined; however, each chemical compound should be treated as a potential health hazard. From this view point, exposure to these chemicals must be reduced to the lowest possible level by whatever means available. The laboratory is responsible for maintaining a current awareness file of OSHA regulations regarding the safe handling of the chemicals specified in this method. A reference file of material data handling sheets should also be made available to all personnel involved in the chemical analysis. Additional references to laboratory safety are available and have been identified \4 6\ for the information of the analyst.

5. Apparatus and Materials

5.1 Sampling equipment, for discrete sampling.

5.1.2 Septum--Teflon-faced silicone (Pierce 12722 or equivalent). Detergent wash, rinse with tap and distilled water and dry at 105 [deg]C for 1 h before use.

5.2 Purge and trap system--The purge and trap system consists of three separate pieces of equipment: a purging device, trap, and desorber. Several complete systems are now commercially available.

5.2.1 The purging device must be designed to accept 5-mL, samples with a water column at least 3 cm deep. The gaseous head space between the water column and the trap must have a total volume of less than 15 mL. The purge gas must pass through the water column as finely divided bubbles with a diameter of less than 3 mm at the origin. The purge gas must be introduced no more than 5 mm from the base of the water column. The purging device must be capable of being heated to 85 [deg]C within 3.0 min after transfer of the sample to the purging device and being held at 85 2 [deg]C during the purge cycle. The entire water column in the purging device must be heated. Design of this modification to the standard purging device is optional, however, use of a water bath is suggested.

5.2.1.1 Heating mantle--To be used to heat water bath.

5.2.1.2 Temperature controller--Equipped with thermocouple/sensor to accurately control water bath temperature to 2 [deg]C. The purging device illustrated in Figure 1 meets these design criteria.

5.2.2 The trap must be at least 25 cm long and have an inside diameter of at least 0.105 in. The trap must be packed to contain 1.0 cm of methyl silicone coated packing (Section 6.5.2) and 23 cm of 2,6-diphenylene oxide polymer (Section 6.5.1). The minimum specifications for the trap are illustrated in Figure 2.

5.2.3 The desorber must be capable of rapidly heating the trap to 180 [deg]C, The desorber illustrated in Figure 2 meets these design criteria.

5.2.4 The purge and trap system may be assembled as a separate unit as illustrated in Figure 3 or be coupled to a gas chromatograph.

5.3 pH paper--Narrow pH range, about 3.5 to 5.5 (Fisher Scientific Short Range Alkacid No. 2, 14-837-2 or equivalent).

5.4 Gas chromatograph--An analytical system complete with a temperature programmable gas chromatograph suitable for on-column injection and all required accessories including syringes, analytical columns, gases, detector, and strip-chart recorder. A data system is recommended for measuring peak areas.

5.4.1 Column 1--10 ft long x 2 mm ID glass or stainless steel, packed with Porapak-QS (80/100 mesh) or equivalent. This column was used to develop the method performance statements in Section 12. Guidelines for the use of alternate column packings are provided in Section 10.1.

5.4.2 Column 2--6 ft long x 0.1 in. ID glass or stainless steel, packed with Chromosorb 101 (60/80 mesh) or equivalent.

5.4.3 Detector--Flame ionization detector. This type of detector has proven effective in the analysis of wastewaters for the parameters listed in the scope (Section 1.1), and was used to develop the method performance statements in Section 12. Guidelines for the use of alternate detectors are provided in Section 10.1.

5.5 Syringes--5-mL, glass hypodermic with Luerlok tip (two each).

5.6 Micro syringes--25-[micro]L, 0.006 in. ID needle.

5.7 Syringe valve--2-way, with Luer ends (three each).

5.8 Bottle--15-mL, screw-cap, with Teflon cap liner.

5.9 Balance--Analytical, capable of accurately weighing 0.0001 g.

6. Reagents

6.1 Reagent water--Reagent water is defined as a water in which an interferent is not observed at the MDL of the parameters of interest.

6.1.1 Reagent water can be generated by passing tap water through a carbon filter bed containing about 1 lb of activated carbon (Filtrasorb-300, Calgon Corp., or equivalent).

6.1.2 A water purification system (Millipore Super-Q or equivalent) may be used to generate reagent water.

6.1.3 Regent water may also be prepared by boiling water for 15 min. Subsequently, while maintaining the temperature at 90 [deg]C, bubble a contaminant-free inert gas through the water for 1 h. While still hot, transfer the water to a narrow mouth screw-cap bottle and seal with a Teflon-lined septum and cap.

6.2 Sodium thiosulfate--(ACS) Granular.

6.3 Sodium hydroxide solution (10 N)--Dissolve 40 g of NaOH (ACS) in reagent water and dilute to 100 mL.

6.4 Hydrochloric acid (1+1)--Slowly, add 50 mL of concentrated HCl (ACS) to 50 mL of reagent water.

6.5 Trap Materials:

6.5.1 2,6-Diphenylene oxide polymer--Tenax (60/80 mesh), chromatographic grade or equivalent.

6.5.2 Methyl silicone packing--3% OV-1 on Chromosorb-W (60/80 mesh) or equivalent.

6.6 Stock standard solutions--Stock standard solutions may be prepared from pure standard materials or purchased as certified solutions. Prepare stock standard solutions in reagent water using assayed liquids. Since acrolein and acrylonitrile are lachrymators, primary dilutions of these compounds should be prepared in a hood. A NIOSH/MESA approved toxic gas respirator should be used when the analyst handles high concentrations of such materials.

6.6.1 Place about 9.8 mL of reagent water into a 10-mL ground glass stoppered volumetric flask. For acrolein standards the reagent water must be adjusted to pH 4 to 5. Weight the flask to the nearest 0.1 mg.

6.6.2 Using a 100-[micro]L syringe, immediately add two or more drops of assayed reference material to the flask, then reweigh. Be sure that the drops fall directly into the water without contacting the neck of the flask.

6.6.3 Reweigh, dilute to volume, stopper, then mix by inverting the flask several times. Calculate the concentration in [micro]g/[micro]L from the net gain in weight. When compound purity is assayed to be 96% or greater, the weight can be used without correction to calculate the concentration of the stock staldard. Optionally, stock standard solutions may be prepared using the pure standard material by volumetrically measuring the appropriate amounts and determining the weight of the material using the density of the material. Commercially prepared stock standards may be used at any concentration if they are certified by the manufactaurer or by an independent source.

6.6.4 Transfer the stock standard solution into a Teflon-sealed screw-cap bottle. Store at 4 [deg]C and protect from light.

6.6.5 Prepare fresh standards daily.

6.7 Secondary dilution standards--Using stock standard solutions, prepare secondary dilution standards in reagent water that contain the compounds of interest, either singly or mixed together. The secondary dilution standards should be prepared at concentrations such that the aqueous calibration standards prepared in Section 7.3.1 or 7.4.1 will bracket the working range of the analytical system. Secondary dilution standards should be prepared daily and stored at 4 [deg]C.

6.8 Quality control check sample concentrate--See Section 8.2.1.

7. Calibration

7.3 External standard calibration procedure:

7.3.1 Prepare calibration standards at a minimum of three concentration levels for each parameter by carefully adding 20.0 [micro]L of one or more secondary dilution standards to 100, 500, or 1000 mL of reagent water. A 25-[micro]L syringe with a 0.006 in. ID needle should be used for this operation. One of the external standards should be at a concentration near, but above, the MDL and the other concentrations should correspond to the expected range of concentrations found in real samples or should define the working range of the detector. These standards must be prepared fresh daily.

7.3.2 Analyze each calibration standard according to Section 10, and tabulate peak height or area responses versus the concentration of the standard. The results can be used to prepare a calibration curve for each compound. Alternatively, if the ratio of response to concentration (calibration factor) is a constant over the working range (<10% relative standard deviation, RSD), linearity through the origin can be assumed and the average ratio or calibration factor can be used in place of a calibration curve.

7.4.1 Prepare calibration standards at a minimum of three concentration levels for each parameter of interest as described in Section 7.3.1.

7.4.2 Prepare a spiking solution containing each of the internal standards using the procedures described in Sections 6.6 and 6.7. It is recommended that the secondary dilution standard be prepared at a concentration of 15 [micro]g/mL of each internal standard compound. The addition of 10 [micro]L of this standard to 5.0 mL of sample or calibration standard would be equivalent to 30 [micro]g/L.

RF = (As)(Cis (Ais)(Cs)

Equation 1 where: As=Response for the parameter to be measured.Ais=Response for the internal standard.Cis=Concentration of the internal standard.Cs=Concentration of the parameter to be measured. If the RF value over the working range is a constant (<10% RSD), the RF can be assumed to be invariant and the average RF can be used for calculations. Alternatively, the results can be used to plot a calibration curve of response ratios, As/Ais, vs. RF.

7.5 The working calibration curve, calibration factor, or RF must be verified on each working day by the measurement of a QC check sample.

7.5.1 Prepare the QC check sample as described in Section 8.2.2.

7.5.2 Analyze the QC check sample according to Section 10.

8. Quality Control

8.1.1 The analyst must make an initial, one-time, demonstration of the ability to generate acceptable accuracy and precision with this method. This ability is established as described in Section 8.2.

8.1.3 Each day, the analyst must analyze a reagent water blank to demonstrate that interferences from the analytical system are under control.

8.1.4 The laboratory must, on an ongoing basis, spike and analyze a minimum of 10% of all samples to monitor and evaluate laboratory data quality. This procedure is described in Section 8.3.

8.1.6 The laboratory must maintain performance records to document the quality of data that is generated. This procedure is described in Section 8.5.

8.2 To establish the ability to generate acceptable accuracy and precision, the analyst must perform the following operations.

8.2.1 A quality control (QC) check sample concentrate is required containing each parameter of interest at a concentration of 25 [micro]g/mL in reagent water. The QC check sample concentrate must be obtained from the U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory in Cincinnati, Ohio, if available. If not available from that source, the QC check sample concentrate must be obtained from another external source. If not available from either source above, the QC check sample concentrate must be prepared by the laboratory using stock standards prepared independently from those used for calibration.

8.2.2 Prepare a QC check sample to contain 50 [micro]g/L of each parameter by adding 200 [micro]L of QC check sample concentrate to 100 mL of reagent water.

8.2.3 Analyze four 5-mL aliquots of the well-mixed QC check sample according to Section 10.

8.2.4 Calculate the average recovery (X) in [micro]g/L, and the standard deviation of the recovery (s) in [micro]g/L, for each parameter using the four results.

8.2.5 For each parameter compare s and X with the corresponding acceptance criteria for precision and accuracy, respectively, found in Table 3. If s and X for all parameters of interest meet the acceptance criteria, the system performance is acceptable and analysis of actual samples can begin. If either s exceeds the precision limit or X falls outside the range for accuracy, the system performance is unacceptable for that parameter. Locate and correct the source of the problem and repeat the test for each compound of interest.

8.3.1 The concentration of the spike in the sample should be determined as follows:

8.3.1.2 If the concentration of a specific parameter in the sample is not being checked against a limit specific to that parameter, the spike should be at 50 [micro]g/L or 1 to 5 times higher than the background concentration determined in Section 8.3.2, whichever concentration would be larger.

8.4 If any parameter fails the acceptance criteria for recovery in Section 8.3, a QC check standard containing each parameter that failed must be prepared and analyzed.

8.4.3 Compare the percent recovery (Ps) for each parameter with the corresponding QC acceptance criteria found in Table 3. Only parameters that failed the test in Section 8.3 need to be compared with these criteria. If the recovery of any such parameter falls outside the designated range, the laboratory performance for that parameter is judged to be out of control, and the problem must be immediately identified and corrected. The analytical result for that parameter in the unspiked sample is suspect and may not be reported for regulatory compliance purposes.

8.5 As part of the QC program for the laboratory, method accuracy for wastewater samples must be assessed and records must be maintained. After the analysis of five spiked wastewater samples as in Section 8.3, calculate the average percent recovery (P) and the standard deviation of the percent recovery (sp). Express the accuracy assessment as a percent recovery interval from P-2sp to P+2sp. If P=90% and sp=10%, for example, the accuracy interval is expressed as 70-110%. Update the accuracy assessment for each parameter on a regular basis (e.g. after each five to ten new accuracy measurements).

8.6 It is recommended that the laboratory adopt additional quality assurance practices for use with this method. The specific practices that are most productive depend upon the needs of the laboratory and the nature of the samples. Field duplicates may be analyzed to assess the precision of the environmental measurements. When doubt exists over the identification of a peak on the chromatogram, confirmatory techniques such as gas chromatography with a dissimilar column or mass spectrometer must be used. Whenever possible, the laboratory should analyze standard reference materials and participate in relevant performance evaluation studies.

9. Sample Collection, Preservation, and Handling

9.2 If acrolein is to be analyzed, collect about 500 mL of sample in a clean glass container. Adjust the pH of the sample to 4 to 5 using acid or base, measuring with narrow range pH paper. Samples for acrolein analysis receiving no pH adjustment must be analyzed within 3 days of sampling.

9.3 Grab samples must be collected in glass containers having a total volume of at least 25 mL. Fill the sample bottle just to overflowing in such a manner that no air bubbles pass through the sample as the bottle is being filled. Seal the bottle so that no air bubbles are entrapped in it. If preservative has been added, shake vigorously for 1 min. Maintain the hermetic seal on the sample bottle until time of analysis.

9.4 All samples must be analyzed within 14 days of collection. \3\

10. Procedure

10.2 Calibrate the system daily as described in Section 7.

10.3 Adjust the purge gas (nitrogen or helium) flow rate to 20 mL-min. Attach the trap inlet to the purging device, and set the purge and trap system to purge (Figure 3). Open the syringe valve located on the purging device sample introduction needle.

10.4 Remove the plunger from a 5-mL syringe and attach a closed syringe valve. Open the sample bottle (or standard) and carefully pour the sample into the syringe barrel to just short of overflowing. Replace the syringe plunger and compress the sample. Open the syringe valve and vent any residual air while adjusting the sample volume to 5.0 mL. Since this process of taking an aliquot destroys the validity of the sample for future analysis, the analyst should fill a second syringe at this time to protect against possible loss of data. Add 10.0 [micro]L of the internal standard spiking solution (Section 7.4.2), if applicable, through the valve bore then close the valve.

10.5 Attach the syringe-syringe valve assembly to the syringe valve on the purging device. Open the syringe valves and inject the sample into the purging chamber.

10.6 Close both valves and purge the sample for 15.0 0.1 min while heating at 85 2 [deg]C.

10.7 After the 15-min purge time, attach the trap to the chromatograph, adjust the purge and trap system to the desorb mode (Figure 4), and begin to temperature program the gas chromatograph. Introduce the trapped materials to the GC column by rapidly heating the trap to 180 [deg]C while backflushing the trap with an inert gas between 20 and 60 mL/min for 1.5 min.

10.8 While the trap is being desorbed into the gas chromatograph, empty the purging chamber using the sample introduction syringe. Wash the chamber with two 5-mL flushes of reagent water.

10.9 After desorbing the sample for 1.5 min, recondition the trap by returning the purge and trap system to the purge mode. Wait 15 s then close the syringe valve on the purging device to begin gas flow through the trap. The trap temperature should be maintained at 210 [deg]C. After approximately 7 min, turn off the trap heater and open the syringe valve to stop the gas flow through the trap. When the trap is cool, the next sample can be analyzed.

11. Calculations

11.1 Determine the concentration of individual compounds in the sample.

Equation 2 where: As=Response for the parameter to be measured.Ais=Response for the internal standard.Cis=Concentration of the internal standard.

11.2 Report results in [micro]g/L without correction for recovery data. All QC data obtained should be reported with the sample results.

12. Method Performance

12.1 The method detection limit (MDL) is defined as the minimum concentration of a substance that can be measured and reported with 99% confidence that the value is above zero. \1\ The MDL concentrations listed in Table 1 were obtained using reagent water. \9\ The MDL actually achieved in a given analysis will vary depending on instrument sensitivity and matrix effects.

12.2 This method is recommended for the concentration range from the MDL to 1,000xMDL. Direct aqueous injection techniques should be used to measure concentration levels above 1,000xMDL.

12.3 In a single laboratory (Battelle-Columbus), the average recoveries and standard deviations presented in Table 2 were obtained. \9\ Seven replicate samples were analyzed at each spike level.

References

1. 40 CFR part 136, appendix B.

2. Bellar, T.A., and Lichtenberg, J.J. ``Determining Volatile Organics at Microgram-per-Litre-Levels by Gas Chromatography,'' Journal American Water Works Association, 66, 739 (1974).

3. ``Evaluate Test Procedures for Acrolein and Acrylonitrile,'' Special letter report for EPA Project 4719-A, U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory, Cincinnati, Ohio 45268, 27 June 1979.

5. ``OSHA Safety and Health Standards, General Industry,'' (29 CFR part 1910), Occupational Safety and Health Administration, OSHA 2206 (Revised, January 1976).

6. ``Safety in Academic Chemistry Laboratories,'' American Chemical Society Publication, Committee on Chemical Safety, 3rd Edition, 1979.

7. Provost, L.P., and Elder, R.S. ``Interpretation of Percent Recovery Data,'' American Laboratory, 15, 58-63 (1983).

8. ``Methods 330.4 (Titrimetric, DPD-FAS) and 330.5 (Spectrophotometric, DPD) for Chlorine, Total Residual,'' Methods for Chemical Analysis of Water and Wastes, EPA-600/4-79-020, U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory, Cincinnati, Ohio 45268, March 1979.

9. ``Evaluation of Method 603 (Modified),'' EPA-600/4-84-ABC, National Technical Information Service, PB84-, Springfield, Virginia 22161, Nov. 1984.

Table 1--Chromatographic Conditions and Method Detection Limits------------------------------------------------------------------------

Retention time (min) Method

------------------------ detection

Parameter limit

Column 1 Column 2 ([micro]g/

L)------------------------------------------------------------------------Acrolein............................ 10.6 8.2 0.7Acrylonitrile....................... 12.7 9.8 0.5------------------------------------------------------------------------Column 1 conditions: Porapak-QS (80/100 mesh) packed in a 10 ft x 2 mm

ID glass or stainless steel column with helium carrier gas at 30 mL/

min flow rate. Column temperature held isothermal at 110 [deg]C for

1.5 min (during desorption), then heated as rapidly as possible to 150

[deg]C and held for 20 min; column bakeout at 190 [deg]C for 10 min.

\9\Column 2 conditions: Chromosorb 101 (60/80 mesh) packed in a 6 ft. x 0.1

in. ID glass or stainless steel column with helium carrier gas at 40

mL/min flow rate. Column temperature held isothermal at 80 [deg]C for

4 min, then programmed at 50 [deg]C/min to 120 [deg]C and held for 12

min.

Table 2--Single Laboratory Accuracy and Precision--Method 603----------------------------------------------------------------------------------------------------------------

Spike Average Standard

Sample conc. recovery deviation Average

Parameter matrix ([micro]g/ ([micro]g/ ([micro]g/ percent

L) L) L) recovery----------------------------------------------------------------------------------------------------------------Acrolein............................................... RW 5.0 5.2 0.2 104

RW 50.0 51.4 0.7 103

POTW 5.0 4.0 0.2 80

POTW 50.0 44.4 0.8 89

IW 5.0 0.1 0.1 2

IW 100.0 9.3 1.1 9Acrylonitrile.......................................... RW 5.0 4.2 0.2 84

RW 50.0 51.4 1.5 103

POTW 20.0 20.1 0.8 100

POTW 100.0 101.3 1.5 101

IW 10.0 9.1 0.8 91

IW 100.0 104.0 3.2 104----------------------------------------------------------------------------------------------------------------RW = Reagent water.POTW = Prechlorination secondary effluent from a municipal sewage treatment plant.IW = Industrial wastewater containing an unidentified acrolein reactant.

Table 3--Calibration and QC Acceptance Criteria--Method 603 \a\----------------------------------------------------------------------------------------------------------------

Limit for

Range for Q S Range for X Range for

Parameter ([micro]g/ ([micro]g/ ([micro]g/ P, Ps (%)

L) L) L)----------------------------------------------------------------------------------------------------------------Acrolein..................................................... 45.9-54.1 4.6 42.9-60.1 88-118Acrylonitrile................................................ 41.2-58.8 9.9 33.1-69.9 71-135----------------------------------------------------------------------------------------------------------------\a\=Criteria were calculated assuming a QC check sample concentration of 50 [micro]g/L. \9\Q = Concentration measured in QC check sample, in [micro]g/L (Section 7.5.3).

s = Standard deviation of four recovery measurements, in [micro]g/L (Section 8.2.4).X = Average recovery for four recovery measurements, in [micro]g/L (Section 8.2.4).P, Ps = Percent recovery measured (Section 8.3.2, Section 8.4.2). [GRAPHIC(S) NOT AVAILABLE IN TIFF FORMAT] [GRAPHIC(S) NOT AVAILABLE IN TIFF FORMAT] [GRAPHIC(S) NOT AVAILABLE IN TIFF FORMAT] [GRAPHIC(S) NOT AVAILABLE IN TIFF FORMAT]

Method 604--Phenols

1. Scope and Application

1.1 This method covers the determination of phenol and certain substituted phenols. The following parameters may be determined by this method: ------------------------------------------------------------------------

STORET

Parameter No. CAS No.------------------------------------------------------------------------4-Chloro-3-methylphenol.......................... 34452 59-50-72--Chlorophenol.................................. 34586 95-57-82,4-Dichlorophenol............................... 34601 120-83-22,4-Dimethylphenol............................... 34606 105-67-92,4-Dinitrophenol................................ 34616 51-28-52-Methyl-4,6-dinitrophenol....................... 34657 534-52-12-Nitrophenol.................................... 34591 88-75-54-Nitrophenol.................................... 34646 100-02-7Pentachlorophenol................................ 39032 87-86-5Phenol........................................... 34694 108-95-22,4,6-Trichlorophenol............................ 34621 88-06-2------------------------------------------------------------------------

1.2 This is a flame ionization detector gas chromatographic (FIDGC) method applicable to the determination of the compounds listed above in municipal and industrial discharges as provided under 40 CFR 136.1. When this method is used to analyze unfamiliar samples for any or all of the compounds above, compound identifications should be supported by at least one additional qualitative technique. This method describes analytical conditions for derivatization, cleanup, and electron capture detector gas chromatography (ECDGC) that can be used to confirm measurements made by FIDGC. Method 625 provides gas chromatograph/mass spectrometer (GC/MS) conditions appropriate for the qualitative and quantitative confirmation of results for all of the parameters listed above, using the extract produced by this method.

1.3 The method detection limit (MDL, defined in Section 14.1) \1\ for each parameter is listed in Table 1. The MDL for a specific wastewater may differ from those listed, depending upon the nature of interferences in the sample matrix. The MDL listed in Table 1 for each parameter was achieved with a flame ionization detector (FID). The MDLs that were achieved when the derivatization cleanup and electron capture detector (ECD) were employed are presented in Table 2.

1.5 This method is restricted to use by or under the supervision of analysts experienced in the use of a gas chromatograph and in the interpretation of gas chromatograms. Each analyst must demonstrate the ability to generate acceptable results with this method using the procedure described in Section 8.2.

2. Summary of Method

2.1 A measured volume of sample, approximately 1-L, is acidified and extracted with methylene chloride using a separatory funnel. The methylene chloride extract is dried and exchanged to 2-propanol during concentration to a volume of 10 mL or less. The extract is separated by gas chromatography and the phenols are then measured with an FID. \2\

2.2 A preliminary sample wash under basic conditions can be employed for samples having high general organic and organic base interferences.

2.3 The method also provides for a derivatization and column chromatography cleanup procedure to aid in the elimination of interferences. \2 3\ The derivatives are analyzed by ECDGC.

3. Interferences

3.1 Method interferences may be caused by contaminants in solvents, reagents, glassware, and other sample processing hardware that lead to discrete artifacts and/or elevated baselines in gas chromatograms. All of these materials must be routinely demonstrated to be free from interferences under the conditions of the analysis by running laboratory reagent blanks as described in Section 8.1.3.

3.1.1 Glassware must be scrupulously cleaned. \4\ Clean all glassware as soon as possible after use by rinsing with the last solvent used in it. Solvent rinsing should be followed by detergent washing with hot water, and rinses with tap water and distilled water. The glassware should then be drained dry, and heated in a muffle furnace at 400 [deg]C for 15 to 30 min. Some thermally stable materials, such as PCBs, may not be eliminated by this treatment. Solvent rinses with acetone and pesticide quality hexane may be substituted for the muffle furnace heating. Thorough rinsing with such solvents usually eliminates PCB interference. Volumetric ware should not be heated in a muffle furnace. After drying and cooling, glassware should be sealed and stored in a clean environment to prevent any accumulation of dust or other contaminants. Store inverted or capped with aluminum foil.

3.1.2 The use of high purity reagents and solvents helps to minimize interference problems. Purification of solvents by distillation in all-glass systems may be required.

3.2 Matrix interferences may be caused by contaminants that are coextracted from the sample. The extent of matrix interferences will vary considerably from source to source, depending upon the nature and diversity of the industrial complex or municipality being sampled. The derivatization cleanup procedure in Section 12 can be used to overcome many of these interferences, but unique samples may require additional cleanup approaches to achieve the MDL listed in Tables 1 and 2.

3.3 The basic sample wash (Section 10.2) may cause significantly reduced recovery of phenol and 2,4-dimethylphenol. The analyst must recognize that results obtained under these conditions are minimum concentrations.

4. Safety

4.1 The toxicity or carcinogenicity of each reagent used in this mothod has not been precisely defined; however, each chemical compound should be treated as a potential health hazard. From this viewpoint, exposure to these chemicals must be reduced to the lowest possible level by whatever means available. The laboratory is responsible for maintaining a current awareness file of OSHA regulations regarding the safe handling of the chemicals specified in this method. A reference file of material data handling sheets should also be made available to all personnel involved in the chemical analysis. Additional references to laboratory safety are available and have been identified \5 7\ for the information of analyst.

4.2 Special care should be taken in handling pentafluorobenzyl bromide, which is a lachrymator, and 18-crown-6-ether, which is highly toxic.

5. Apparatus and Materials

5.1 Sampling equipment, for discrete or composite sampling.

5.1.1 Grab sample bottle--1-L or 1-qt, amber glass, fitted with a screw cap lined with Teflon. Foil may be substituted for Teflon if the sample is not corrosive. If amber bottles are not available, protect samples from light. The bottle and cap liner must be washed, rinsed with acetone or methylene chloride, and dried before use to minimize contamination.

5.1.2 Automatic sampler (optional)--The sampler must incorporate glass sample containers for the collection of a minimum of 250 mL of sample. Sample containers must be kept refrigerated at 4 [deg]C and protected from light during compositing. If the sampler uses a peristaltic pump, a minimum length of compressible silicone rubber tubing may be used. Before use, however, the compressible tubing should be thoroughly rinsed with methanol, followed by repeated rinsings with distilled water to minimize the potential for contamination of the sample. An integrating flow meter is required to collect flow proportional composites.

5.2 Glassware (All specifications are suggested. Catalog numbers are included for illustration only.):

5.2.1 Separatory funnel--2-L, with Teflon stopcock.

5.2.2 Drying column--Chromatographic column, 400 mm long x 19 mm ID, with coarse frit filter disc.

5.2.3 Chromatographic column--100 mm long x 10 mm ID, with Teflon stopcock.

5.2.4 Concentrator tube, Kuderna-Danish--10-mL, graduated (Kontes K-570050-1025 or equivalent). Calibration must be checked at the volumes employed in the test. Ground glass stopper is used to prevent evaporation of extracts.

5.2.5 Evaporative flask, Kuderna-Danish--500-mL (Kontes K-570001-0500 or equivalent). Attach to concentrator tube with springs.

5.2.6 Snyder column, Kuderna-Danish--Three-ball macro (Kontes K-503000-0121 or equivalent).

5.2.7 Snyder column, Kuderna-Danish--Two-ball micro (Kontes K-569001-0219 or equivalent).

5.2.8 Vials--10 to 15-mL, amber glass, with Teflon-lined screw cap.

5.2.9 Reaction flask--15 to 25-mL round bottom flask, with standard tapered joint, fitted with a water-cooled condenser and U-shaped drying tube containing granular calcium chloride.

5.3 Boiling chips--Approximately 10/40 mesh. Heat to 400 [deg]C for 30 min or Soxhlet extract with methylene chloride.

5.4 Water bath--Heated, with concentric ring cover, capable of temperature control (2 [deg]C). The bath should be used in a hood.

5.5 Balance--Analytical, capable of accurately weighting 0.0001 g.

5.6 Gas chromatograph--An analytical system complete with a temperature programmable gas chromatograph suitable for on-column injection and all required accessories including syringes, analytical columns, gases, detector, and strip-chart recorder. A data system is recommended for measuring peak areas.

5.6.1 Column for underivatized phenols--1.8 m long x 2 mm ID glass, packed with 1% SP-1240DA on Supelcoport (80/100 mesh) or equivalent. This column was used to develop the method performance statements in Section 14. Guidelines for the use of alternate column packings are provided in Section 11.1.

5.6.2 Column for derivatized phenols--1.8 m long x 2 mm ID glass, packed with 5% OV-17 on Chromosorb W-AW-DMCS (80/100 mesh) or equivalent. This column has proven effective in the analysis of wastewaters for derivatization products of the parameters listed in the scope (Section 1.1), and was used to develop the method performance statements in Section 14. Guidelines for the use of alternate column packings are provided in Section 11.1.

5.6.3 Detectors--Flame ionization and electron capture detectors. The FID is used when determining the parent phenols. The ECD is used when determining the derivatized phenols. Guidelines for the use of alternatve detectors are provided in Section 11.1.

6. Reagents

6.1 Reagent water--Reagent water is defined as a water in which an interferent is not observed at the MDL of the parameters of interest.

6.2 Sodium hydroxide solution (10 N)--Dissolve 40 g of NaOH (ACS) in reagent water and dilute to 100 mL.

6.3 Sodium hydroxide solution (1 N)--Dissolve 4 g of NaOH (ACS) in reagent water and dilute to 100 mL.

6.4 Sodium sulfate--(ACS) Granular, anhydrous. Purify by heating at 400 [deg]C for 4 h in a shallow tray.

6.5 Sodium thiosulfate--(ACS) Granular.

6.6 Sulfuric acid (1+1)--Slowly, add 50 mL of H2SO4 (ACS, sp. gr. 1.84) to 50 mL of reagent water.

6.7 Sulfuric acid (1 N)--Slowly, add 58 mL of H2SO4 (ACS, sp. gr. 1.84) to reagent water and dilute to 1 L.

6.8 Potassium carbonate--(ACS) Powdered.

6.9 Pentafluorobenzyl bromide ([alpha]-Bromopentafluorotoluene)--97% minimum purity.

Note: This chemical is a lachrymator. (See Section 4.2.)

6.10 18-crown-6-ether (1,4,7,10,13,16-Hexaoxacyclooctadecane)--98% minimum purity.

Note: This chemical is highly toxic.

6.11 Derivatization reagent--Add 1 mL of pentafluorobenzyl bromide and 1 g of 18-crown-6-ether to a 50-mL volumetric flask and dilute to volume with 2-propanol. Prepare fresh weekly. This operation should be carried out in a hood. Store at 4 [deg]C and protect from light.

6.12 Acetone, hexane, methanol, methylene chloride, 2-propanol, toluene--Pesticide quality or equivalent.

6.13 Silica gel--100/200 mesh, Davison, grade-923 or equivalent. Activate at 130 [deg]C overnight and store in a desiccator.

6.14 Stock standard solutions (1.00 [micro]g/[micro]L)--Stock standard solutions may be prepared from pure standard materials or purchased as certified solutions.

6.14.1 Prepare stock standard solutions by accurately weighing about 0.0100 g of pure material. Dissolve the material in 2-propanol and dilute to volume in a 10-mL volumetric flask. Larger volumes can be used at the convenience of the analyst. When compound purity is assayed to be 96% or greater, the weight can be used without correction to calculate the concentration of the stock standard. Commercially prepared stock standards can be used at any concentration if they are certified by the manufacturer or by an independent source.

6.14.2 Transfer the stock standard solutions into Teflon-sealed screw-cap bottles. Store at 4 [deg]C and protect from light. Stock standard solutions should be checked frequently for signs of degradation or evaporation, especially just prior to preparing calibration standards from them.

6.14.3 Stock standard solutions must be replaced after six months, or sooner if comparison with check standards indicates a problem.

6.15 Quality control check sample concentrate--See Section 8.2.1.

7. Calibration

7.1 To calibrate the FIDGC for the anaylsis of underivatized phenols, establish gas chromatographic operating conditions equivalent to those given in Table 1. The gas chromatographic system can be calibrated using the external standard technique (Section 7.2) or the internal standard technique (Section 7.3).

7.2 External standard calibration procedure for FIDGC:

7.2.1 Prepare calibration standards at a minimum of three concentration levels for each parameter of interest by adding volumes of one or more stock standards to a volumetric flask and diluting to volume with 2-propanol. One of the external standards should be at a concentration near, but above, the MDL (Table 1) and the other concentrations should correspond to the expected range of concentrations found in real samples or should define the working range of the detector.

7.2.2 Using injections of 2 to 5 [micro]l, analyze each calibration standard according to Section 11 and tabulate peak height or area responses against the mass injected. The results can be used to prepare a calibration curve for each compound. Alternatively, if the ratio of response to amount injected (calibration factor) is a constant over the working range (<10% relative standard deviation, RSD), linearity through the origin can be assumed and the average ratio or calibration factor can be used in place of a calibration curve.

7.3 Internal standard calibration procedure for FIDGC--To use this approach, the analyst must select one or more internal standards that are similar in analytical behavior to the compounds of interest. The analyst must further demonstrate that the measurement of the internal standard is not affected by method or matrix interferences. Because of these limitations, no internal standard can be suggested that is applicable to all samples.

7.3.1 Prepare calibration standards at a minimum of three concentration levels for each parameter of interest by adding volumes of one or more stock standards to a volumetric flask. To each calibration standard, add a known constant amount of one or more internal standards, and dilute to volume with 2-propanol. One of the standards should be at a concentration near, but above, the MDL and the other concentrations should correspond to the expected range of concentrations found in real samples or should define the working range of the detector.

7.3.2 Using injections of 2 to 5 [micro]L, analyze each calibration standard according to Section 11 and tabulate peak height or area responses against concentration for each compound and internal standard. Calculate response factors (RF) for each compound using Equation 1.

RF = (As)(Cis (Ais)(Cs)

Equation 1 where:As=Response for the parameter to be measured.Ais=Response for the internal standard.Cis=Concentration of the internal standard ([micro]g/L). Cs=Concentration of the parameter to be measured ([micro]g/

L).

If the RF value over the working range is a constant (<10% RSD), the RF can be assumed to be invariant and the average RF can be used for calculations. Alternatively, the results can be used to plot a calibration curve of response ratios, As/Ais, vs. RF.

7.4 The working calibration curve, calibration factor, or RF must be verified on each working day by the measurement of one or more calibration standards. If the response for any parameter varies from the predicted response by more than 15%, a new calibration curve must be prepared for that compound.

7.5 To calibrate the ECDGC for the analysis of phenol derivatives, establish gas chromatographic operating conditions equivalent to those given in Table 2.

7.5.1 Prepare calibration standards at a minimum of three concentration levels for each parameter of interest by adding volumes of one or more stock standards to a volumetric flask and diluting to volume with 2-propanol. One of the external standards should be at a concentration near, but above, the MDL (Table 2) and the other concentrations should correspond to the expected range of concentrations found in real samples or should define the working range of the detector.

7.5.2 Each time samples are to be derivatized, simultaneously treat a 1-mL aliquot of each calibration standard as described in Section 12.

7.5.3 After derivatization, analyze 2 to 5 [micro]L of each column eluate collected according to the method beginning in Section 12.8 and tabulate peak height or area responses against the calculated equivalent mass of underivatized phenol injected. The results can be used to prepare a calibration curve for each compound.

7.6 Before using any cleanup procedure, the analyst must process a series of calibration standards through the procedure to validate elution patterns and the absence of interferences from the reagents.

8. Quality Control

8.1.1 The analyst must make an initial, one-time, demonstration of the ability to generate acceptable accuracy and precision with this method. This ability is established as described in Section 8.2.

8.1.2 In recognition of advances that are occurring in chromatography, the analyst is permitted certain options (detailed in Sections 10.6 and 11.1) to improve the separations or lower the cost of measurements. Each time such a modification is made to the method, the analyst is required to repeat the procedure in Section 8.2.

8.1.3 Before processing any samples the analyst must analyze a reagent water blank to demonstrate that interferences from the analytical system and glassware are under control. Each time a set of samples is extracted or reagents are changed a reagent water blank must be processed as a safeguard against laboratory contamination.

8.1.4 The laboratory must, on an ongoing basis, spike and analyze a minimum of 10% of all samples to monitor and evaluate laboratory data quality. This procedure is described in Section 8.3.

8.1.6 The laboratory must maintain performance records to document the quality of data that is generated. This procedure is described in Section 8.5.

8.2 To establish the ability to generate acceptable accuracy and precision, the analyst must perform the following operations.

8.2.1 A quality control (QC) check sample concentrate is required containing each parameter of interest at a concentration of 100 [micro]g/mL in 2-propanol. The QC check sample concentrate must be obtained from the U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory in Cincinnati, Ohio, if available. If not available from that source, the QC check sample concentrate must be obtained from another external source. If not available from either source above, the QC check sample concentrate must be prepared by the laboratory using stock standards prepared independently from those used for calibration.

8.2.2 Using a pipet, prepare QC check samples at a concentration of 100 [micro]g/L by adding 1.00 mL of QC check sample concentrate to each of four 1-L aliquots of reagent water.

8.2.3 Analyze the well-mixed QC check samples according to the method beginning in Section 10.

8.2.4 Calculate the average recovery (X) in [micro]g/L, and the standard deviation of the recovery (s) in [micro]g/L, for each parameter using the four results.

8.2.5 For each parameter compare s and X with the corresponding acceptance criteria for precision and accuracy, respectively, found in Table 3. If s and X for all parameters of interest meet the acceptance criteria, the system performance is acceptable and analysis of actual samples can begin. If any individual s exceeds the precision limit or any individual X falls outside the range for accuracy, the system performance is unacceptable for that parameter.

Note: The large number of parameters in Talbe 3 present a substantial probability that one or more will fail at least one of the acceptance criteria when all parameters are analyzed.

8.2.6 When one or more of the parameters tested fail at least one of the acceptance criteria, the analyst must proceed according to Section 8.2.6.1 or 8.2.6.2.

8.2.6.1 Locate and correct the source of the problem and repeat the test for all parameters of interest beginning with Section 8.2.2.

8.2.6.2 Beginning with Section 8.2.2, repeat the test only for those parameters that failed to meet criteria. Repeated failure, however, will confirm a general problem with the measurement system. If this occurs, locate and correct the source of the problem and repeat the test for all compounds of interest beginning with Section 8.2.2.

8.3.1 The concentration of the spike in the sample should be determined as follows:

8.3.1.2 If the concentration of a specific parameter in the sample is not being checked against a limit specific to that parameter, the spike should be at 100 [micro]g/L or 1 to 5 times higher than the background concentration determined in Section 8.3.2, whichever concentration would be larger.

8.3.1.3 If it is impractical to determine background levels before spiking (e.g., maximum holding times will be exceeded), the spike concentration should be (1) the regulatory concentration limit, if any, or, if none, (2) the larger of either 5 times higher than the expected background concentration or 100 [micro]g/L.

8.3.2 Analyze one sample aliquot to determine the background concentration (B) of each parameter. If necessary, prepare a new QC check sample concentrate (Section 8.2.1) appropriate for the background concentrations in the sample. Spike a second sample aliquot with 1.0 mL of the QC check sample concentrate and analyze it to determine the concentration after spiking (A) of each parameter. Calculate each percent recovery (P) as 100(A-B)%/T, where T is the known true value of the spike.

8.3.3 Compare the percent recovery (P) for each parameter with the corresponding QC acceptance criteria found in Table 3. These acceptance criteria were calculated to include an allowance for error in measurement of both the background and spike concentrations, assuming a spike to background ratio of 5:1. This error will be accounted for to the extent that the analyst's spike to background ratio approaches 5:1. \8\ If spiking was performed at a concentration lower than 100 [micro]g/L, the analyst must use either the QC acceptance criteria in Table 3, or optional QC acceptance criteria calculated for the specific spike concentration. To calculate optional acceptance criteria for the recovery of a parameter: (1) Calculate accuracy (X') using the equation in Table 4, substituting the spike concentration (T) for C; (2) calculate overall precision (S') using the equation in Table 4, substituting X' for X; (3) calculate the range for recovery at the spike concentration as (100 X'/T)2.44(100 S'/T)%. \8\

8.4 If any parameter fails the acceptance criteria for recovery in Section 8.3, a QC check standard containing each parameter that failed must be prepared and analyzed.

8.4.1 Prepare the QC check standard by adding 1.0 mL of QC check sample concentrate (Section 8.2.1 or 8.3.2) to 1 L of reagent water. The QC check standard needs only to contain the parameters that failed criteria in the test in Section 8.3.

8.5 As part of the QC program for the laboratory, method accuracy for wastewater samples must be assessed and records must be maintained. After the analysis of five spiked wastewater samples as in Section 8.3, calculate the average percent recovery (P) and the standard deviation of the percent recovery (sp). Express the accuracy assessment as a percent recovery interval from P-2sp to P+2sp. If P=90% and sp=10%, for example, the accuracy interval is expressed as 70-110%. Update the accuracy assessment for each parameter on a regular basis (e.g. after each five to ten new accuracy measurements).

8.6. It is recommended that the laboratory adopt additional quality assurance practices for use with this method. The specific practices that are most productive depend upon the needs of the laboratory and the nature of the samples. Field duplicates may be analyzed to assess the precision of the environmental measurements. When doubt exists over the identification of a peak on the chromatogram, confirmatory techniques such as gas chromatography with a dissimilar column, specific element detector, or mass spectrometer must be used. Whenever possible, the laboratory should analyze standard reference materials and participate in relevant performance evaluation studies.

9. Sample Collection, Preservation, and Handling

9.1 Grab samples must be collected in glass containers. Conventional sampling practices \9\ should be followed, except that the bottle must not be prerinsed with sample before collection. Composite samples should be collected in refrigerated glass containers in accordance with the requirements of the program. Automatic sampling equipment must be as free as possible of Tygon tubing and other potential sources of contamination.

9.2 All samples must be iced or refrigerated at 4 [deg]C from the time of collection until extraction. Fill the sample bottles and, if residual chlorine is present, add 80 mg of sodium thiosulfate per liter of sample and mix well. EPA Methods 330.4 and 330.5 may be used for measurement of residual chlorine. \10\ Field test kits are available for this purpose.

9.3 All samples must be extracted within 7 days of collection and completely analyzed within 40 days of extraction. \2\

10. Sample Extraction

10.1 Mark the water meniscus on the side of sample bottle for later determination of sample volume. Pour the entire sample into a 2-L separatory funnel.

10.2 For samples high in organic content, the analyst may solvent wash the sample at basic pH as prescribed in Sections 10.2.1 and 10.2.2 to remove potential method interferences. Prolonged or exhaustive contact with solvent during the wash may result in low recovery of some of the phenols, notably phenol and 2,4-dimethylphenol. For relatively clean samples, the wash should be omitted and the extraction, beginning with Section 10.3, should be followed.

10.2.1 Adjust the pH of the sample to 12.0 or greater with sodium hydroxide solution.

10.2.2 Add 60 mL of methylene chloride to the sample by shaking the funnel for 1 min with periodic venting to release excess pressure. Discard the solvent layer. The wash can be repeated up to two additional times if significant color is being removed.

10.3 Adjust the sample to a pH of 1 to 2 with sulfuric acid.

10.4 Add 60 mL of methylene chloride to the sample bottle, seal, and shake 30 s to rinse the inner surface. Transfer the solvent to the separatory funnel and extract the sample by shaking the funnel for 2 min. with periodic venting to release excess pressure. Allow the organic layer to separate from the water phase for a minimum of 10 min. If the emulsion interface between layers is more than one-third the volume of the solvent layer, the analyst must employ mechanical techniques to complete the phase separation. The optimum technique depends upon the sample, but may include stirring, filtration of the emulsion through glass wool, centrifugation, or other physical methods. Collect the methylene chloride extract in a 250-mL Erlenmeyer flask.

10.5 Add a second 60-mL volume of methylene chloride to the sample bottle and repeat the extraction procedure a second time, combining the extracts in the Erlenmeyer flask. Perform a third extraction in the same manner.

10.6 Assemble a Kuderna-Danish (K-D) concentrator by attaching a 10-mL concentrator tube to a 500-mL evaporative flask. Other concentration devices or techniques may be used in place of the K-D concentrator if the requirements of Section 8.2 are met.

10.7 Pour the combined extract through a solvent-rinsed drying column containing about 10 cm of anhydrous sodium sulfate, and collect the extract in the K-D concentrator. Rinse the Erlenmeyer flask and column with 20 to 30 mL of methylene chloride to complete the quantitative transfer.

10.8 Add one or two clean boiling chips to the evaporative flask and attach a three-ball Snyder column. Prewet the Snyder column by adding about 1 mL of methylene chloride to the top. Place the K-D apparatus on a hot water bath (60 to 65 [deg]C) so that the concentrator tube is partially immersed in the hot water, and the entire lower rounded surface of the flask is bathed with hot vapor. Adjust the vertical position of the apparatus and the water temperature as required to complete the concentration in 15 to 20 min. At the proper rate of distillation the balls of the column will actively chatter but the chambers will not flood with condensed solvent. When the apparent volume of liquid reaches 1 mL, remove the K-D apparatus and allow it to drain and cool for at least 10 min.

10.9 Increase the temperature of the hot water bath to 95 to 100 [deg]C. Remove the Synder column and rinse the flask and its lower joint into the concentrator tube with 1 to 2 mL of 2-propanol. A 5-mL syringe is recommended for this operation. Attach a two-ball micro-Snyder column to the concentrator tube and prewet the column by adding about 0.5 mL of 2-propanol to the top. Place the micro-K-D apparatus on the water bath so that the concentrator tube is partially immersed in the hot water. Adjust the vertical position of the apparatus and the water temperature as required to complete concentration in 5 to 10 min. At the proper rate of distillation the balls of the column will actively chatter but the chambers will not flood. When the apparent volume of liquid reaches 2.5 mL, remove the K-D apparatus and allow it to drain and cool for at least 10 min. Add an additional 2 mL of 2-propanol through the top of the micro-Snyder column and resume concentrating as before. When the apparent volume of liquid reaches 0.5 mL, remove the K-D apparatus and allow it to drain and cool for at least 10 min.

10.10 Remove the micro-Snyder column and rinse its lower joint into the concentrator tube with a minimum amount of 2-propanol. Adjust the extract volume to 1.0 mL. Stopper the concentrator tube and store refrigerated at 4 [deg]C if further processing will not be performed immediately. If the extract will be stored longer than two days, it should be transferred to a Teflon-sealed screw-cap vial. If the sample extract requires no further cleanup, proceed with FIDGC analysis (Section 11). If the sample requires further cleanup, proceed to Section 12.

10.11 Determine the original sample volume by refilling the sample bottle to the mark and transferring the liquid to a 1000-mL graduated cylinder. Record the sample volume to the nearest 5 mL.

11. Flame Ionization Detector Gas Chromatography

11.1 Table 1 summarizes the recommended operating conditions for the gas chromatograph. Included in this table are retention times and MDL that can be achieved under these conditions. An example of the separations achieved by this column is shown in Figure 1. Other packed or capillary (open-tubular) columns, chromatographic conditions, or detectors may be used if the requirements of Section 8.2 are met.

11.2 Calibrate the system daily as described in Section 7.

11.3 If the internal standard calibration procedure is used, the internal standard must be added to the sample extract and mixed thoroughly immediately before injection into the gas chromatograph.

11.4 Inject 2 to 5 [micro]L of the sample extract or standard into the gas chromatograph using the solvent-flush technique. \11\ Smaller (1.0 [micro]L) volumes may be injected if automatic devices are employed. Record the volume injected to the nearest 0.05 [micro]L, and the resulting peak size in area or peak height units.

11.5 Identify the parameters in the sample by comparing the retention times of the peaks in the sample chromatogram with those of the peaks in standard chromatograms. The width of the retention time window used to make identifications should be based upon measurements of actual retention time variations of standards over the course of a day. Three times the standard deviation of a retention time for a compound may be used to calculate a suggested window size; however, the experience of the analyst should weigh heavily in the interpretation of chromatograms.

11.6 If the response for a peak exceeds the working range of the system, dilute the extract and reanalyze.

11.7 If the measurement of the peak response is prevented by the presence of interferences, an alternative gas chromatographic procedure is required. Section 12 describes a derivatization and column chromatographic procedure which has been tested and found to be a practical means of analyzing phenols in complex extracts.

12. Derivatization and Electron Capture Detector Gas Chromatography

12.1 Pipet a 1.0-mL aliquot of the 2-propanol solution of standard or sample extract into a glass reaction vial. Add 1.0 mL of derivatizing reagent (Section 6.11). This amount of reagent is sufficient to derivatize a solution whose total phenolic content does not exceed 0.3 mg/mL.

12.2 Add about 3 mg of potassium carbonate to the solution and shake gently.

12.3 Cap the mixture and heat it for 4 h at 80 [deg]C in a hot water bath.

12.4 Remove the solution from the hot water bath and allow it to cool.

12.5 Add 10 mL of hexane to the reaction flask and shake vigorously for 1 min. Add 3.0 mL of distilled, deionized water to the reaction flask and shake for 2 min. Decant a portion of the organic layer into a concentrator tube and cap with a glass stopper.

12.6 Place 4.0 g of silica gel into a chromatographic column. Tap the column to settle the silica gel and add about 2 g of anhydrous sodium sulfate to the top.

12.7 Preelute the column with 6 mL of hexane. Discard the eluate and just prior to exposure of the sodium sulfate layer to the air, pipet onto the column 2.0 mL of the hexane solution (Section 12.5) that contains the derivatized sample or standard. Elute the column with 10.0 mL of hexane and discard the eluate. Elute the column, in order, with: 10.0 mL of 15% toluene in hexane (Fraction 1); 10.0 mL of 40% toluene in hexane (Fraction 2); 10.0 mL of 75% toluene in hexane (Fraction 3); and 10.0 mL of 15% 2-propanol in toluene (Fraction 4). All elution mixtures are prepared on a volume: volume basis. Elution patterns for the phenolic derivatives are shown in Table 2. Fractions may be combined as desired, depending upon the specific phenols of interest or level of interferences.

12.8 Analyze the fractions by ECDGC. Table 2 summarizes the recommended operating conditions for the gas chromatograph. Included in this table are retention times and MDL that can be achieved under these conditions. An example of the separations achieved by this column is shown in Figure 2.

12.9 Calibrate the system daily with a minimum of three aliquots of calibration standards, containing each of the phenols of interest that are derivatized according to Section 7.5.

12.10 Inject 2 to 5 [micro]L of the column fractions into the gas chromatograph using the solvent-flush technique. Smaller (1.0 [micro]L) volumes can be injected if automatic devices are employed. Record the volume injected to the nearest 0.05 [micro]L, and the resulting peak size in area or peak height units. If the peak response exceeds the linear range of the system, dilute the extract and reanalyze.

13. Calculations

13.1 Determine the concentration of individual compounds in the sample analyzed by FIDGC (without derivatization) as indicated below.

13.1.1 If the external standard calibration procedure is used, calculate the amount of material injected from the peak response using the calibration curve or calibration factor determined in Section 7.2.2. The concentration in the sample can be calculated from Equation 2. [GRAPHIC(S) NOT AVAILABLE IN TIFF FORMAT]

Equation 2 where:A=Amount of material injected (ng).Vi=Volume of extract injected ([micro]L).Vt=Volume of total extract ([micro]L).Vs=Volume of water extracted (mL).

13.1.2 If the internal standard calibration procedure is used, calculate the concentration in the sample using the response factor (RF) determined in Section 7.3.2 and Equation 3. [GRAPHIC(S) NOT AVAILABLE IN TIFF FORMAT]

Equation 3 where:As=Response for the parameter to be measured.Ais=Response for the internal standard.Is=Amount of internal standard added to each extract

([micro]g).Vo=Volume of water extracted (L).

13.2 Determine the concentration of individual compounds in the sample analyzed by derivatization and ECDGC according to Equation 4. [GRAPHIC(S) NOT AVAILABLE IN TIFF FORMAT]

Equation 4 where:A=Mass of underivatized phenol represented by area of peak in sample

chromatogram, determined from calibration curve in Section

7.5.3 (ng).Vi=Volume of eluate injected ([micro]L).Vt=Total volume of column eluate or combined fractions from

which Vi was taken ([micro]L).Vs=Volume of water extracted in Section 10.10 (mL).B=Total volume of hexane added in Section 12.5 (mL).C=Volume of hexane sample solution added to cleanup column in Section

12.7 (mL).D=Total volume of 2-propanol extract prior to derivatization (mL).E=Volume of 2-propanol extract carried through derivatization in Section

12.1 (mL).

13.3 Report results in [micro]g/L without correction for recovery data. All QC data obtained should be reported with the sample results.

14. Method Performance

14.1 The method detection limit (MDL) is defined as the minimum concentration of a substance that can be measured and reported with 99% confidence that the value is above zero. \1\ The MDL concentrations listed in Tables 1 and 2 were obtained using reagent water. \12\ Similar results were achieved using representative wastewaters. The MDL actually achieved in a given analysis will vary depending on instrument sensitivity and matrix effects.

14.2 This method was tested by 20 laboratories using reagent water, drinking water, surface water, and three industrial wastewaters spiked as six concentrations over the range 12 to 450 [micro]g/L. \13\ Single operator precision, overall precision, and method accuracy were found to be directly related to the concentration of the parameter and essentially independent of the sample matrix. Linear equations to describe these relationships for a flame ionization detector are presented in Table 4.

References

1. 40 CFR part 136, appendix B.

2. ``Determination of Phenols in Industrial and Municipal Wastewaters,'' EPA 600/4-84-ABC, National Technical Information Service, PBXYZ, Springfield, Virginia 22161, November 1984.

3. Kawahara, F. K. ``Microdetermination of Derivatives of Phenols and Mercaptans by Means of Electron Capture Gas Chromatography,'' Analytical Chemistry, 40, 1009 (1968).

4. ASTM Annual Book of Standards, Part 31, D3694-78. ``Standard Practices for Preparation of Sample Containers and for Preservation of Organic Constituents,'' American Society for Testing and Materials, Philadelphia.

5. ``Carcinogens--Working With Carcinogens,'' Department of Health, Education, and Welfare, Public Health Service, Center for Disease Control, National Institute for Occupational Safety and Health, Publication No. 77-206, August 1977.

6. ``OSHA Safety and Health Standards, General Industry,'' (29 CFR part 1910), Occupational Safety and Health Administration, OSHA 2206 (Revised, January 1976).

7. ``Safety in Academic Chemistry Laboratories,'' American Chemical Society Publication, Committee on Chemical Safety, 3rd Edition, 1979.

8. Provost, L. P., and Elder, R. S. ``Interpretation of Percent Recovery Data,'' American Laboratory, 15, 58-63 (1983). (The value 2.44 used in the equation in Section 8.3.3 is two times the value 1.22 derived in this report.)

9. ASTM Annual Book of Standards, Part 31, D3370-76. ``Standard Practices for Sampling Water,'' American Society for Testing and Materials, Philadelphia.

10. ``Methods 330.4 (Titrimetric, DPD-FAS) and 330.5 (Spectrophotometric, DPD) for Chlorine, Total Residual,'' Methmds for Chemical Analysis of Water and Wastes, EPA-600/4-79-020, U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory, Cincinnati, Ohio 45268, March 1979.

11. Burke, J. A. ``Gas Chromatography for Pesticide Residue Analysis; Some Practical Aspects,'' Journal of the Association of Official Analytical Chemists, 48, 1037 (1965).

12. ``Development of Detection Limits, EPA Method 604, Phenols,'' Special letter report for EPA Contract 68-03-2625, U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory, Cincinnati, Ohio 45268.

13. ``EPA Method Study 14 Method 604-Phenols,'' EPA 600/4-84-044, National Technical Information Service, PB84-196211, Springfield, Virginia 22161, May 1984.

Table 1--Chromatographic Conditions and Method Detection Limits------------------------------------------------------------------------

Method

Retention detection

Parameter time (min) limit

([micro]g/L)------------------------------------------------------------------------2-Chlorophenol................................ 1.70 0.312-Nitrophenol................................. 2.00 0.45Phenol........................................ 3.01 0.142,4-Dimethylphenol............................ 4.03 0.322,4-Dichlorophenol............................ 4.30 0.392,4,6-Trichlorophenol......................... 6.05 0.644-Chloro-3-methylphenol....................... 7.50 0.362,4-Dinitrophenol............................. 10.00 13.02-Methyl-4,6-dinitrophenol.................... 10.24 16.0Pentachlorophenol............................. 12.42 7.44-Nitrophenol................................. 24.25 2.8------------------------------------------------------------------------Column conditions: Supelcoport (80/100 mesh) coated with 1% SP-1240DA

packed in a 1.8 m long x 2 mm ID glass column with nitrogen carrier

gas at 30 mL/min flow rate. Column temperature was 80 [deg]C at

injection, programmed immediately at 8 [deg]C/min to 150 [deg]C final

temperature. MDL were determined with an FID.

Table 2--Silica Gel Fractionation and Electron Capture Gas Chromatography of PFBB Derivatives----------------------------------------------------------------------------------------------------------------

Percent recovery by Method

fraction \a\ Retention detection

Parent compound ---------------------------- time limit

(min) ([micro]g/

1 2 3 4 L)----------------------------------------------------------------------------------------------------------------2-Chlorophenol............................................... ..... 90 1 ..... 3.3 0.582-Nitrophenol................................................ ..... ..... 9 90 9.1 0.77Phenol....................................................... ..... 90 10 ..... 1.8 2.22,4-Dimethylphenol........................................... ..... 95 7 ..... 2.9 0.632,4-Dichlorophenol........................................... ..... 95 1 ..... 5.8 0.682,4,6-Trichlorophenol........................................ 50 50 ..... ..... 7.0 0.584-Chloro-3-methylphenol...................................... ..... 84 14 ..... 4.8 1.8Pentachlorophenol............................................ 75 20 ..... ..... 28.8 0.594-Nitrophenol................................................ ..... ..... 1 90 14.0 0.70----------------------------------------------------------------------------------------------------------------Column conditions: Chromosorb W-AW-DMCS (80/100 mesh) coated with 5% OV-17 packed in a 1.8 m long x 2.0 mm ID

glass column with 5% methane/95% argon carrier gas at 30 mL/min flow rate. Column temperature held isothermal

at 200 [deg]C. MDL were determined with an ECD.

\a\ Eluant composition:

Fraction 1--15% toluene in hexane.

Fraction 2--40% toluene in hexane.

Fraction 3--75% toluene in hexane.

Fraction 4--15% 2-propanol in toluene.

Table 3--QC Acceptance Criteria--Method 604----------------------------------------------------------------------------------------------------------------

Limit for

Test conc. s Range for X Range for

Parameter ([micro]g/ ([micro]g/ ([micro]g/ P, Ps

L) L) L) (percent)----------------------------------------------------------------------------------------------------------------4-Chloro-3-methylphenol....................................... 100 16.6 56.7-113.4 49-1222-Chlorophenol................................................ 100 27.0 54.1-110.2 38-1262,4-Dichlorophenol............................................ 100 25.1 59.7-103.3 44-1192,4-Dimethylphenol............................................ 100 33.3 50.4-100.0 24-1184,6-Dinitro-2-methylphenol.................................... 100 25.0 42.4-123.6 30-1362,4-Dinitrophenol............................................. 100 36.0 31.7-125.1 12-1452-Nitrophenol................................................. 100 22.5 56.6-103.8 43-1174-Nitrophenol................................................. 100 19.0 22.7-100.0 13-110Pentachlorophenol............................................. 100 32.4 56.7-113.5 36-134Phenol........................................................ 100 14.1 32.4-100.0 23-1082,4,6-Trichlorophenol......................................... 100 16.6 60.8-110.4 53-119----------------------------------------------------------------------------------------------------------------s--Standard deviation of four recovery measurements, in [micro]g/L (Section 8.2.4).X--Average recovery for four recovery measurements, in [micro]g/L (Section 8.2.4).P, Ps--Percent recovery measured (Section 8.3.2, Section 8.4.2).

Note: These criteria are based directly upon the method performance data in Table 4. Where necessary, the limits

for recovery have been broadened to assure applicability of the limits to concentrations below those used to

develop Table 4.

Table 4--Method Accuracy and Precision as Functions of Concentration--Method 604----------------------------------------------------------------------------------------------------------------

Accuracy, as Single Analyst Overall

Parameter recovery, X' precision, sr' precision, S'

[micro]g/L.S'=Expected interlaboratory standard deviation of measurements at an average concentration found of X, in

Method 605--Benzidines

1. Scope and Application

1.1 This method covers the determination of certain benzidines. The following parameters can be determined by this method: ------------------------------------------------------------------------

Parameter Storet No CAS No.------------------------------------------------------------------------Benzidine..................................... 39120 92-87-53,3'-Dichlorobenzidine........................ 34631 91-94-1------------------------------------------------------------------------

1.2 This is a high performance liquid chromatography (HPLC) method applicable to the determination of the compounds listed above in municipal and industrial discharges as provided under 40 CFR 136.1. When this method is used to analyze unfamiliar samples for the compounds above, identifications should be supported by at least one additional qualitative technique. This method describes electrochemical conditions at a second potential which can be used to confirm measurements made with this method. Method 625 provides gas chromatograph/mass spectrometer (GC/MS) conditions appropriate for the qualitative and quantitative confirmation of results for the parameters listed above, using the extract produced by this method.

1.5 This method is restricted to use by or under the supervision of analysts experienced in the use of HPLC instrumentation and in the interpretation of liquid chromatograms. Each analyst must demonstrate the ability to generate acceptable results with this method using the procedure described in Section 8.2.

2. Summary of Method

2.1 A measured volume of sample, approximately 1-L, is extracted with chloroform using liquid-liquid extractions in a separatory funnel. The chloroform extract is extracted with acid. The acid extract is then neutralized and extracted with chloroform. The final chloroform extract is exchanged to methanol while being concentrated using a rotary evaporator. The extract is mixed with buffer and separated by HPLC. The benzidine compounds are measured with an electrochemical detector. \2\

2.2 The acid back-extraction acts as a general purpose cleanup to aid in the elimination of interferences.

3. Interferences

3.1 Method interferences may be caused by contaminants in solvents, reagents, glassware, and other sample processing hardware that lead to discrete artifacts and/or elevated baselines in chromatograms. All of these materials must be routinely demonstrated to be free from interferences under the conditions of the analysis by running laboratory reagent blanks as described in Section 8.1.3.

3.1.1 Glassware must be scrupulously cleaned. \3\ Clean all glassware as soon as possible after use by rinsing with the last solvent used in it. Solvent rinsing should be followed by detergent washing with hot water, and rinses with tap water and distilled water. The glassware should then be drained dry, and heated in a muffle furnace at 400 [deg]C for 15 to 30 min. Some thermally stable materials may not be eliminated by this treatment. Solvent rinses with acetone and pesticide quality hexane may be substituted for the muffle furnace heating. Volumetric ware should not be heated in a muffle furnace. After drying and cooling, glassware should be sealed and stored in a clean environment to prevent any accumulation of dust or other contaminants. Store inverted or capped with aluminum foil.

3.1.2 The use of high purity reagents and solvents helps to minimize interference problems. Purification of solvents by distillation in all-glass systems may be required.

3.2 Matrix interferences may be caused by contaminants that are co-extracted from the sample. The extent of matrix interferences will vary considerably from source to source, depending upon the nature and diversity of the industrial complex or municipality being sampled. The cleanup procedures that are inherent in the extraction step are used to overcome many of these interferences, but unique samples may require additional cleanup approaches to achieve the MDL listed in Table 1.

3.3 Some dye plant effluents contain large amounts of components with retention times closed to benzidine. In these cases, it has been found useful to reduce the electrode potential in order to eliminate interferences and still detect benzidine. (See Section 12.7.)

4. Safety

4.1 The toxicity or carcinogenicity of each reagent used in this method has not been precisely defined; however, each chemical compound should be treated as a potential health harzard. From this viewpoint, exposure to these chemicals must be reduced to the lowest possible level by whatever means available. The laboratory is responsible for maintaining a current awareness file of OSHA regulations regarding the safe handling of the chemicals specified in this method. A reference file of material data handling sheets should also be made available to all personnel involved in the chemical analysis. Additional references to laboratory safety are available and have been identified \4 6\ for the information of the analyst.

4.2 The following parameters covered by this method have been tentatively classified as known or suspected, human or mammalian carcinogens: benzidine and 3,3'-dichlorobenzidine. Primary standards of these toxic compounds should be prepared in a hood. A NIOSH/MESA approved toxic gas respirator should be worn when the analyst handles high concentrations of these toxic compounds.

4.3 Exposure to chloroform should be minimized by performing all extractions and extract concentrations in a hood or other well-ventiliated area.

5. Apparatus and Materials

5.1 Sampling equipment, for discrete or composite sampling.

5.2 Glassware (All specifications are suggested):

5.2.1 Separatory funnels--2000, 1000, and 250-mL, with Teflon stopcock.

5.2.2 Vials--10 to 15-mL, amber glass, with Teflon-lined screw cap.

5.2.3 Rotary evaporator.

5.2.4 Flasks--Round bottom, 100-mL, with 24/40 joints.

5.2.5 Centrifuge tubes--Conical, graduated, with Teflon-lined screw caps.

5.2.6 Pipettes--Pasteur, with bulbs.

5.3 Balance--Analytical, capable of accurately weighing 0.0001 g.

5.4 High performance liquid chromatograph (HPLC)--An analytical system complete with column supplies, high pressure syringes, detector, and compatible recorder. A data system is recommended for measuring peak areas and retention times.

5.4.1 Solvent delivery system--With pulse damper, Altex 110A or equivalent.

5.4.2 Injection valve (optional)--Waters U6K or equivalent.

5.4.3 Electrochemical detector--Bioanalytical Systems LC-2A with glassy carbon electrode, or equivalent. This detector has proven effective in the analysis of wastewaters for the parameters listed in the scope (Section 1.1), and was used to develop the method performance statements in Section 14. Guidelines for the use of alternate detectors are provided in Section 12.1.

5.4.4 Electrode polishing kit--Princeton Applied Research Model 9320 or equivalent.

5.4.5 Column--Lichrosorb RP-2, 5 micron particle diameter, in a 25 cm x 4.6 mm ID stainless steel column. This column was used to develop the method performance statements in Section 14. Guidelines for the use of alternate column packings are provided in Section 12.1.

6. Reagents

6.1 Reagent water--Reagent water is defined as a water in which an interferent is not observed at the MDL of the parameters of interest.

6.2 Sodium hydroxide solution (5 N)--Dissolve 20 g of NaOH (ACS) in reagent water and dilute to 100 mL.

6.3 Sodium hydroxide solution (1 M)--Dissolve 40 g of NaOH (ACS) in reagent water and dilute to 1 L.

6.4 Sodium thiosulfate--(ACS) Granular.

6.5 Sodium tribasic phosphate (0.4 M)--Dissolve 160 g of trisodium phosphate decahydrate (ACS) in reagent water and dilute to 1 L.

6.6 Sulfuric acid (1+1)--Slowly, add 50 mL of H2SO4 (ACS, sp. gr. 1.84) to 50 mL of reagent water.

6.7 Sulfuric acid (1 M)--Slowly, add 58 mL of H2SO4 (ACS, sp. gr. 1.84) to reagent water and dilute to 1 L.

6.8 Acetate buffer (0.1 M, pH 4.7)--Dissolve 5.8 mL of glacial acetic acid (ACS) and 13.6 g of sodium acetate trihydrate (ACS) in reagent water which has been purified by filtration through a RO-4 Millipore System or equivalent and dilute to 1 L.

6.9 Acetonitrile, chloroform (preserved with 1% ethanol), methanol--Pesticide quality or equivalent.

6.10 Mobile phase--Place equal volumes of filtered acetonitrile (Millipore type FH filter or equivalent) and filtered acetate buffer (Millipore type GS filter or equivalent) in a narrow-mouth, glass container and mix thoroughly. Prepare fresh weekly. Degas daily by sonicating under vacuum, by heating and stirring, or by purging with helium.

6.11 Stock standard solutions (1.00 [micro]g/[micro]L)--Stock standard solutions may be prepared from pure standard materials or purchased as certified solutions.

6.11.1 Prepare stock standard solutions by accurately weighing about 0.0100 g of pure material. Dissolve the material in methanol and dilute to volume in a 10-mL volumetric flask. Larger volumes can be used at the convenience of the analyst. When compound purity is assayed to be 96% or greater, the weight can be used without correction to calculate the concentration of the stock standard. Commercially prepared stock standards can be used at any concentration if they are certified by the manufacturer or by an independent source.

6.11.2 Transfer the stock standard solutions into Teflon-sealed screw-cap bottles. Store at 4 [deg]C and protect from light. Stock standard solutions should be checked frequently for signs of degradation or evaporation, especially just prior to preparing calibration standards from them.

6.11.3 Stock standard solutions must be replaced after six months, or sooner if comparison with check standards indicates a problem.

6.12 Quality control check sample concentrate--See Section 8.2.1.

7. Calibration

7.1 Establish chromatographic operating conditions equivalent to those given in Table 1. The HPLC system can be calibrated using the external standard technique (Section 7.2) or the internal standard technique (Section 7.3).

7.2 External standard calibration procedure:

7.2.1 Prepare calibration standards at a minimum of three concentration levels for each parameter of interest by adding volumes of one or more stock standards to a volumetric flask and diluting to volume with mobile phase. One of the external standards should be at a concentration near, but above, the MDL (Table 1) and the other concentrations should correspond to the expected range of concentrations found in real samples or should define the working range of the detector.

7.2.2 Using syringe injections of 5 to 25 [micro]L or a constant volume injection loop, analyze each calibration standard according to Section 12 and tabulate peak height or area responses against the mass injected. The results can be used to prepare a calibration curve for each compound. Alternatively, if the ratio of response to amount injected (calibration factor) is a constant over the working range (<10% relative standard deviation, RSD), linearity through the origin can be assumed and the average ratio or calibration factor can be used in place of a calibration curve.

7.3 Internal standard calibration procedure--To use this approach, the analyst must select one or more internal standards that are similar in analytical behavior to the compounds of interest. The analyst must further demonstrate that the measurement of the internal standard is not affected by method or matrix interferences. Because of these limitations, no internal standard can be suggested that is applicable to all samples.

7.3.1 Prepare calibration standards at a minimum of three concentration levels for each parameter of interest by adding volumes of one or more stock standards to a volumetric flask. To each calibration standard, add a known constant amount of one or more internal standards, and dilute to volume with mobile phase. One of the standards should be at a concentration near, but above, the MDL and the other concentrations should correspond to the expected range of concentrations found in real samples or should define the working range of the detector.

7.3.2 Using syringe injections of 5 to 25 [micro]L or a constant volume injection loop, analyze each calibration standard according to Section 12 and tabulate peak height or area responses against concentration for each compound and internal standard. Calculate response factors (RF) for each compound using Equation 1.

RF = (As)(Cis (Ais)(Cs)

Equation 1 where:As=Response for the parameter to be measured.Ais=Response for the internal standard.Cis=Concentration of the internal standard ([micro]g/L).Cs=Concentration of the parameter to be measured ([micro]g/

L).

7.5 Before using any cleanup procedure, the analyst must process a series of calibration standards through the procedure to validate elution patterns and the absence of interferences from the reagents.

8. Quality Control

8.1.1 The analyst must make an initial, one-time, demonstration of the ability to generate acceptable accuracy and precision with this method. This ability is established as described in Section 8.2.

8.1.2 In recognition of advances that are occurring in chromatography, the analyst is permitted certain options (detailed in Sections 10.9, 11.1, and 12.1) to improve the separations or lower the cost of measurements. Each time such a modification is made to the method, the analyst is required to repeat the procedure in Section 8.2.

8.1.3 Before processing any samples, the analyst must analyze a reagent water blank to demonstrate that interferences from the analytical system and glassware are under control. Each time a set of samples is extracted or reagents are changed, a reagent water blank must be processed as a safeguard against laboratory contamination.

8.1.4 The laboratory must, on an ongoing basis, spike and analyze a minimum of 10% of all samples to monitor and evaluate laboratory data quality. This procedure is described in Section 8.3.

8.1.6 The laboratory must maintain performance records to document the quality of data that is generated. This procedure is described in Section 8.5.

8.2 To establish the ability to generate acceptable accuracy and precision, the analyst must perform the following operations.

8.2.1 A quality control (QC) check sample concentrate is required containing benzidine and/or 3,3'-dichlorobenzidine at a concentration of 50 [micro]g/mL each in methanol. The QC check sample concentrate must be obtained from the U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory in Cincinnati, Ohio, if available. If not available from that source, the QC check sample concentrate must be obtained from another external source. If not available from either source above, the QC check sample concentrate must be prepared by the laboratory using stock standards prepared independently from those used for calibration.

8.2.2 Using a pipet, prepare QC check samples at a concentration of 50 [micro]g/L by adding 1.00 mL of QC check sample concentrate to each of four 1-L-L aliquots of reagent water.

8.2.3 Analyze the well-mixed QC check samples according to the method beginning in Section 10.

8.2.4 Calculate the average recovery (X) in [micro]g/L, and the standard deviation of the recovery (s) in [micro]g/L, for each parameter using the four results.

8.2.5 For each parameter compare s and X with the corresponding acceptance criteria for precision and accuracy, respectively, found in Table 2. If s and X for all parameters of interest meet the acceptance criteria, the system performance is acceptable and analysis of actual samples can begin. If any individual s exceeds the precision limit or any individual X falls outside the range for accuracy, the system performance is unacceptable for that parameter. Locate and correct the source of the problem and repeat the test for all parameters of interest beginning with Section 8.2.2.

8.3.1 The concentration of the spike in the sample should be determined as follows:

8.3.1.3 If it is impractical to determine background levels before spiking (e.g., maximum holding times will be exceeded), the spike concentration should be (1) the regulatory concentration limit, if any; or, if none (2) the larger of either 5 times higher than the expected background concentration or 50 [micro]g/L.

8.3.3 Compare the percent recovery (P) for each parameter with the corresponding QC acceptance criteria found in Table 2. These acceptance criteria were calculated to include an allowance for error in measurement of both the background and spike concentrations, assuming a spike to background ratio of 5:1. This error will be accounted for to the extent that the analyst's spike to background ratio approaches 5:1. \7\ If spiking was performed at a concentration lower than 50 [micro]g/L, the analyst must use either the QC acceptance criteria in Table 2, or optional QC acceptance criteria calculated for the specific spike concentration. To calculate optional acceptance criteria for the recovery of a parameter: (1) Calculate accuracy (X') using the equation in Table 3, substituting the spike concentration (T) for C; (2) calculate overall precision (S') using the equation in Table 3, substituting X' for X; (3) calculate the range for recovery at the spike concentration as (100 X'/T)2.44(100 S'/T)%. \7\

8.4 If any parameter fails the acceptance criteria for recovery in Section 8.3, a QC check standard containing each parameter that failed must be prepared and analyzed.

8.4.1 Prepare the QC check standard by adding 1.0 mL of QC check sample concentrate (Sections 8.2.1 or 8.3.2) to 1 L of reagent water. The QC check standard needs only to contain the parameters that failed criteria in the test in Section 8.3.

8.5 As part of the QC program for the laboratory, method accuracy for wastewater samples must be assessed and records must be maintained. After the analysis of five spiked wastewater samples as in Section 8.3, calculate the average percent recovery (P) and the standard deviation of the percent recovery (sp). Express the accuracy assessment as a percent recovery interval from P-2sp to P+2sp. If P=90% and sp=10%, for example, the accuracy interval is expressed as 70-110%. Update the accuracy assessment for each parameter on a regular basis (e.g. after each five to ten new accuracy measurements).

8.6 It is recommended that the laboratory adopt additional quality assurance practices for use with this method. The specific practices that are most productive depend upon the needs of the laboratory and the nature of the samples. Field duplicates may be analyzed to assess the precision of the environmental measurements. When doubt exists over the identification of a peak on the chromatogram, confirmatory techniques such as HPLC with a dissimilar column, gas chromatography, or mass spectrometer must be used. Whenever possible, the laboratory should analyze standard reference materials and participate in relevant performance evaluation studies.

9. Sample Collection, Preservation, and Handling

9.1 Grab samples must be collected in glass containers. Conventional sampling practices \8\ should be followed, except that the bottle must not be prerinsed with sample before collection. Composite samples should be collected in refrigerated glass containers in accordance with the requirements of the program. Automatic sampling equipment must be as free as possible of Tygon tubing and other potential sources of contamination.

9.2 All samples must be iced or refrigerated at 4 [deg]C and stored in the dark from the time of collection until extraction. Both benzidine and 3,3'-dichlorobenzidine are easily oxidized. Fill the sample bottles and, if residual chlorine is present, add 80 mg of sodium thiosulfate per liter of sample and mix well. EPA Methods 330.4 and 330.5 may be used for measurement of residual chlorine. \9\ Field test kits are available for this purpose. After mixing, adjust the pH of the sample to a range of 2 to 7 with sulfuric acid.

9.3 If 1,2-diphenylhydrazine is likely to be present, adjust the pH of the sample to 4.0 0.2 to prevent rearrangement to benzidine.

9.4 All samples must be extracted within 7 days of collection. Extracts may be held up to 7 days before analysis, if stored under an inert (oxidant free) atmosphere. \2\ The extract should be protected from light.

10. Sample Extraction

10.1 Mark the water meniscus on the side of the sample bottle for later determination of sample volume. Pour the entire sample into a 2-L separatory funnel. Check the pH of the sample with wide-range pH paper and adjust to within the range of 6.5 to 7.5 with sodium hydroxide solution or sulfuric acid.

10.2 Add 100 mL of chloroform to the sample bottle, seal, and shake 30 s to rinse the inner surface. (Caution: Handle chloroform in a well ventilated area.) Transfer the solvent to the separatory funnel and extract the sample by shaking the funnel for 2 min with periodic venting to release excess pressure. Allow the organic layer to separate from the water phase for a minimum of 10 min. If the emulsion interface between layers is more than one-third the volume of the solvent layer, the analyst must employ mechanical techniques to complete the phase separation. The optimum technique depends upon the sample, but may include stirring, filtration of the emulsion through glass wool, centrifugation, or other physical methods. Collect the chloroform extract in a 250-mL separatory funnel.

10.3 Add a 50-mL volume of chloroform to the sample bottle and repeat the extraction procedure a second time, combining the extracts in the separatory funnel. Perform a third extraction in the same manner.

10.4 Separate and discard any aqueous layer remaining in the 250-mL separatory funnel after combining the organic extracts. Add 25 mL of 1 M sulfuric acid and extract the sample by shaking the funnel for 2 min. Transfer the aqueous layer to a 250-mL beaker. Extract with two additional 25-mL portions of 1 M sulfuric acid and combine the acid extracts in the beaker.

10.5 Place a stirbar in the 250-mL beaker and stir the acid extract while carefully adding 5 mL of 0.4 M sodium tribasic phosphate. While monitoring with a pH meter, neutralize the extract to a pH between 6 and 7 by dropwise addition of 5 N sodium hydroxide solution while stirring the solution vigorously. Approximately 25 to 30 mL of 5 N sodium hydroxide solution will be required and it should be added over at least a 2-min period. Do not allow the sample pH to exceed 8.

10.6 Transfer the neutralized extract into a 250-mL separatory funnel. Add 30 mL of chloroform and shake the funnel for 2 min. Allow the phases to separate, and transfer the organic layer to a second 250-mL separatory funnel.

10.7 Extract the aqueous layer with two additional 20-mL aliquots of chloroform as before. Combine the extracts in the 250-mL separatory funnel.

10.8 Add 20 mL of reagent water to the combined organic layers and shake for 30 s.

10.9 Transfer the organic extract into a 100-mL round bottom flask. Add 20 mL of methanol and concentrate to 5 mL with a rotary evaporator at reduced pressure and 35 [deg]C. An aspirator is recommended for use as the source of vacuum. Chill the receiver with ice. This operation requires approximately 10 min. Other concentration techniques may be used if the requirements of Section 8.2 are met.

10.10 Using a 9-in. Pasteur pipette, transfer the extract to a 15-mL, conical, screw-cap centrifuge tube. Rinse the flask, including the entire side wall, with 2-mL portions of methanol and combine with the original extract.

10.11 Carefully concentrate the extract to 0.5 mL using a gentle stream of nitrogen while heating in a 30 [deg]C water bath. Dilute to 2 mL with methanol, reconcentrate to 1 mL, and dilute to 5 mL with acetate buffer. Mix the extract thoroughly. Cap the centrifuge tube and store refrigerated and protected from light if further processing will not be performed immediately. If the extract will be stored longer than two days, it should be transferred to a Teflon-sealed screw-cap vial. If the sample extract requires no further cleanup, proceed with HPLC analysis (Section 12). If the sample requires further cleanup, proceed to Section 11.

10.12 Determine the original sample volume by refilling the sample bottle to the mark and transferring the liquid to a 1,000-mL graduated cylinder. Record the sample volume to the nearest 5 mL.

11. Cleanup and Separation

11.1 Cleanup procedures may not be necessary for a relatively clean sample matrix. If particular circumstances demand the use of a cleanup procedure, the analyst first must demonstrate that the requirements of Section 8.2 can be met using the method as revised to incorporate the cleanup procedure.

12. High Performance Liquid Chromatography

12.1 Table 1 summarizes the recommended operating conditions for the HPLC. Included in this table are retention times, capacity factors, and MDL that can be achieved under these conditions. An example of the separations achieved by this HPLC column is shown in Figure 1. Other HPLC columns, chromatographic conditions, or detectors may be used if the requirements of Section 8.2 are met. When the HPLC is idle, it is advisable to maintain a 0.1 mL/min flow through the column to prolong column life.

12.2 Calibrate the system daily as described in Section 7.

12.3 If the internal standard calibration procedure is being used, the internal standard must be added to the sample extract and mixed thoroughly immediately before injection into the instrument.

12.4 Inject 5 to 25 [micro]L of the sample extract or standard into the HPLC. If constant volume injection loops are not used, record the volume injected to the nearest 0.05 [micro]L, and the resulting peak size in area or peak height units.

12.5 Identify the parameters in the sample by comparing the retention times of the peaks in the sample chromatogram with those of the peaks in standard chromatograms. The width of the retention time window used to make identifications should be based upon measurements of actual retention time variations of standards over the course of a day. Three times the standard deviation of a retention time for a compound can be used to calculate a suggested window size; however, the experience of the analyst should weigh heavily in the interpretation of chromatograms.

12.6 If the response for a peak exceeds the working range of the system, dilute the extract with mobile phase and reanalyze.

12.7 If the measurement of the peak response for benzidine is prevented by the presence of interferences, reduce the electrode potential to +0.6 V and reanalyze. If the benzidine peak is still obscured by interferences, further cleanup is required.

13. Calculations

13.1 Determine the concentration of individual compounds in the sample.

Equation 2 where:A=Amount of material injected (ng).Vi=Volume of extract injected ([micro]L).Vt=Volume of total extract ([micro]L).Vs=Volume of water extracted (mL).

Equation 3 where:As=Response for the parameter to be measured.Ais=Response for the internal standard.Is=Amount of internal standard added to each extract

([micro]g).Vo=Volume of water extracted (L).

13.2 Report results in [micro]g/L without correction for recovery data. All QC data obtained should be reported with the sample results.

14. Method Performance

14.1 The method detection limit (MDL) is defined as the minimum concentration of a substance that can be measured and reported with 99% confidence that the value is above zero. \1\ The MDL concentrations listed in Table 1 were obtained using reagent water. \10\ Similar results were achieved using representative wastewaters. The MDL actually achieved in a given analysis will vary depending on instrument sensitivity and matrix effects.

14.2 This method has been tested for linearity of spike recovery from reagent water and has been demonstrated to be applicable over the concentration range from 7xMDL to 3000xMDL. \10\

14.3 This method was tested by 17 laboratories using reagent water, drinking water, surface water, and three industrial wastewaters spiked at six concentrations over the range 1.0 to 70 [micro]g/L. \11\ Single operator precision, overall precision, and method accuracy were found to be directly related to the concentration of the parameter and essentially independent of the sample matrix. Linear equations to describe these relationships are presented in Table 3.

References

1. 40 CFR part 136, appendix B.

2. ``Determination of Benzidines in Industrial and Muncipal Wastewaters,'' EPA 600/4-82-022, National Technical Information Service, PB82-196320, Springfield, Virginia 22161, April 1982.

3. ASTM Annual Book of Standards, Part 31, D3694-78. ``Standard Practices for Preparation of Sample Containers and for Preservation of Organic Constituents,'' American Society for Testing and Materials, Philadelphia.

5. ``OSHA Safety and Health Standards, General Industry,'' (29 CFR part 1910), Occupational Safety and Health Administration, OSHA 2206 (Revised, January 1976).

6. ``Safety in Academic Chemistry Laboratories,'' American Chemical Society Publication, Committee on Chemical Safety, 3rd Edition, 1979.

8. ASTM Annual Book of Standards, Part 31, D3370-76. ``Standard Practices for Sampling Water,'' American Society for Testing and Materials, Philadelphia.

9. ``Methods 330.4 (Titrimetric, DPD-FAS) and 330.5 (Spectrophotometric, DPD) for Chlorine Total Residual,'' Methods for Chemical Analysis of Water and Wastes, EPA-600/4-79-020, U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory, Cincinnati, Ohio 45268, March 1979.

10. ``EPA Method Study 15, Method 605 (Benzidines),'' EPA 600/4-84-062, National Technical Information Service, PB84-211176, Springfield, Virginia 22161, June 1984.

11. ``EPA Method Validation Study 15, Method 605 (Benzidines),'' Report for EPA Contract 68-03-2624 (In preparation).

Table 1--Chromatographic Conditions and Method Detection Limits------------------------------------------------------------------------

Method

Column detection

Parameter Retention capacity limit

time (min) factor (k') ([micro]g/

L)------------------------------------------------------------------------Benzidine........................ 6.1 1.44 0.083,3'-Dichlorobenzidine........... 12.1 3.84 0.13------------------------------------------------------------------------HPLC Column conditions: Lichrosorb RP-2, 5 micron particle size, in a 25

cmx4.6 mm ID stainless steel column. Mobile Phase: 0.8 mL/min of 50%

acetonitrile/50% 0.1M pH 4.7 acetate buffer. The MDL were determined

using an electrochemical detector operated at +0.8 V.

Table 2--QC Acceptance Criteria--Method 605----------------------------------------------------------------------------------------------------------------

Limit for Range for

Test conc. s X Range for

Parameter ([micro]g/ ([micro]g/ ([micro]g/ P, Ps

L) L) L) (percent)----------------------------------------------------------------------------------------------------------------Benzidine........................................................ 50 18.7 9.1-61.0 D-1403.3'-Dichlorobenzidine........................................... 50 23.6 18.7-50.0 5-128----------------------------------------------------------------------------------------------------------------s=Standard deviation of four recovery measurements, in [micro]g/L (Section 8.2.4).X=Average recovery for four recovery measurements, in [micro]g/L (Section 8.2.4).P, Ps=Percent recovery measured (Section 8.3.2, Section 8.4.2).D=Detected; result must be greater than zero.

Note: These criteria are based directly upon the method performance data in Table 3. Where necessary, the limits

for recovery have been broadened to assure applicability of the limits to concentrations below those used to

develop Table 3.

Table 3--Method Accuracy and Precision as Functions of Concentration--Method 605----------------------------------------------------------------------------------------------------------------

Accuracy, as Single analyst Overall

Parameter recovery, precision, sr' precision, S'

X'([micro]g/L) ([micro]g/L) ([micro]g/L)----------------------------------------------------------------------------------------------------------------Benzidine....................................................... 0.70C+0.06 0.28X+0.19 0.40X+0.183,3'-Dichlorobenzidine.......................................... 0.66C+0.23 0.39X-0.05 0.38X+0.02----------------------------------------------------------------------------------------------------------------X'=Expected recovery for one or more measurements of a sample containing a concentration of C, in [micro]g/L.sr'=Expected single analyst standard deviation of measurements at an average concentration found of X, in

[micro]g/L.S'=Expected interlaboratory standard deviation of measurements at an average concentration found of X, in

Method 606--Phthalate Ester

1. Scope and Application

1.1 This method covers the determination of certain phthalate esters. The following parameters can be determined by this method: ------------------------------------------------------------------------

STORET

Parameter No. CAS No.------------------------------------------------------------------------Bis(2-ethylhexyl) phthalate........................ 39100 117-81-7Butyl benzyl phthalate............................. 34292 85-68-7Di-n-butyl phthalate............................... 39110 84-74-2Diethyl phthalate.................................. 34336 84-66-2Dimethyl phthalate................................. 34341 131-11-3Di-n-octyl phthalate............................... 34596 117-84-0------------------------------------------------------------------------

1.2 This is a gas chromatographic (GC) method applicable to the determination of the compounds listed above in municipal and industrial discharges as provided under 40 CFR 136.1. When this method is used to analyze unfamiliar samples for any or all of the compounds above, compound identifications should be supported by at least one additional qualitative technique. This method describes analytical conditions for a second gas chromatographic column that can be used to confirm measurements made with the primary column. Method 625 provides gas chromatograph/mass spectrometer (GC/MS) conditions appropriate for the qualitative and quantitative confirmation of results for all of the parameters listed above, using the extract produced by this method.

1.4 The sample extraction and concentration steps in this method are essentially the same as in Methods 608, 609, 611, and 612. Thus, a single sample may be extracted to measure the parameters included in the scope of each of these methods. When cleanup is required, the concentration levels must be high enough to permit selecting aliquots, as necessary, to apply appropriate cleanup procedures. The analyst is allowed the latitude, under Section 12, to select chromatographic conditions appropriate for the simultaneous measurement of combinations of these parameters.

1.5 Any modification of this method, beyond those expressly permitted, shall be considered as a major modification subject to application and approval of alternate test procedures under 40 CFR 136.4 and 136.5.

1.6 This method is restricted to use by or under the supervision of analysts experienced in the use of a gas chromatograph and in the interpretation of gas chromatograms. Each analyst must demonstrate the ability to generate acceptable results with this method using the procedure described in Section 8.2.

2. Summary of Method

2.1 A measured volume of sample, approximately 1-L, is extracted with methylene chloride using a separatory funnel. The methylene chloride extract is dried and exchanged to hexane during concentration to a volume of 10 mL or less. The extract is separated by gas chromatography and the phthalate esters are then measured with an electron capture detector. \2\

2.2 Analysis for phthalates is especially complicated by their ubiquitous occurrence in the environment. The method provides Florisil and alumina column cleanup procedures to aid in the elimination of interferences that may be encountered.

3. Interferences

3.1.1 Glassware must be scrupulously cleaned. \3\ Clean all glassware as soon as possible after use by rinsing with the last solvent used in it. Solvent rinsing should be followed by detergent washing with hot water, and rinses with tap water and distilled water. The glassware should then be drained dry, and heated in a muffle furnace at 400 [deg]C for 15 to 30 min. Some thermally stable materials, such as PCBs, may not be eliminated by this treatment. Solvent rinses with acetone and pesticide quality hexane may be substituted for the muffle furnace heating. Thorough rinsing with such solvents usually eliminates PCB interference. Volumetric ware should not be heated in a muffle furnace. After drying and cooling, glassware should be sealed and stored in a clean environment to prevent any accumulation of dust or other contaminants. Store inverted or capped with aluminum foil.

3.1.2 The use of high purity reagents and solvents helps to minimize interference problems. Purification of solvents by distillation in all-glass systems may be required.

3.2 Phthalate esters are contaminants in many products commonly found in the laboratory. It is particularly important to avoid the use of plastics because phthalates are commonly used as plasticizers and are easily extracted from plastic materials. Serious phthalate contamination can result at any time, if consistent quality control is not practiced. Great care must be experienced to prevent such contamination. Exhaustive cleanup of reagents and glassware may be required to eliminate background phthalate contamination. \4 5\

3.3 Matrix interferences may be caused by contaminants that are co-extracted from the sample. The extent of matrix interferences will vary considerably from source to source, depending upon the nature and diversity of the industrial complex or municipality being sampled. The cleanup procedures in Section 11 can be used to overcome many of these interferences, but unique samples may require additional cleanup approaches to achieve the MDL listed in Table 1.

4. Safety

5. Apparatus and Materials

5.1 Sampling equipment, for discrete or composite sampling.

5.2 Glassware (All specifications are suggested. Catalog numbers are included for illustration only).

5.2.1 Separatory funnel--2-L, with Teflon stopcock.

5.2.2 Drying column--Chromatographic column, approximately 400 mm long x 19 mm ID, with coarse frit filter disc.

5.2.3 Chromatographic column--300 mm long x 10 mm ID, with Teflon stopcock and coarse frit filter disc at bottom (Kontes K-420540-0213 or equivalent).

5.2.5 Evaporative flask, Kuderna-Danish--500-mL (Kontes K-570001-0500 or equivalent). Attach to concentrator tube with springs.

5.2.6 Snyder column, Kuderna-Danish--Three-ball macro (Kontes K-503000-0121 or equivalent).

5.2.7 Snyder column, Kuderna-Danish--Two-ball micro (Kontes K-569001-0219 or equivalent).

5.2.8 Vials--10 to 15-mL, amber glass, with Teflon-lined screw cap.

5.3 Boiling chips--Approximately 10/40 mesh. Heat to 400 [deg]C for 30 min or Soxhlet extract with methylene chloride.

5.4 Water bath--Heated, with concentric ring cover, capable of temperature control (2 [deg]C). The bath should be used in a hood.

5.5 Balance--Analytical, capable of accurately weighing 0.0001 g.

5.6 Gas chromatograph--An analytical system complete with gas chromatograph suitable for on-column injection and all required accessories including syringes, analytical columns, gases, detector, and strip-chart recorder. A data system is recommended for measuring peak areas.

5.6.1 Column 1--1.8 m long x 4 mm ID glass, packed with 1.5% SP-2250/1.95% SP-2401 Supelcoport (100/120 mesh) or equivalent. This column was used to develop the method performance statemelts in Section 14. Guidelines for the use of alternate column packings are provided in Section 12.1.

5.6.2 Column 2--1.8 m long x 4 mm ID glass, packed with 3% OV-1 on Supelcoport (100/120 mesh) or equivalent.

5.6.3 Detector--Electron capture detector. This detector has proven effective in the analysis of wastewaters for the parameters listed in the scope (Section 1.1), and was used to develop the method performance statements in Section 14. Guidelines for the use of alternate detectors are provided in Section 12.1.

6. Reagents

6.1 Reagent water--Reagent water is defined as a water in which an interferent is not observed at the MDL of the parameters of interest.

6.2 Acetone, hexane, isooctane, methylene chloride, methanol--Pesticide quality or equivalent.

6.3 Ethyl ether--nanograde, redistilled in glass if necessary.

6.3.1 Ethyl ether must be shown to be free of peroxides before it is used as indicated by EM Laboratories Quant test strips. (Available from Scientific Products Co., Cat. No. P1126-8, and other suppliers.)

6.3.2 Procedures recommended for removal of peroxides are provided with the test strips. After cleanup, 20 mL of ethyl alcohol preservative must be added to each liter of ether.

6.4 Sodium sulfate--(ACS) Granular, anhydrous. Several levels of purification may be required in order to reduce background phthalate levels to an acceptable level: 1) Heat 4 h at 400 [deg]C in a shallow tray, 2) Heat 16 h at 450 to 500 [deg]C in a shallow tray, 3) Soxhlet extract with methylene chloride for 48 h.

6.5 Florisil--PR grade (60/100 mesh). Purchase activated at 1250 [deg]F and store in the dark in glass containers with ground glass stoppers or foil-lined screw caps. To prepare for use, place 100 g of Florisil into a 500-mL beaker and heat for approximately 16 h at 40 [deg]C. After heating transfer to a 500-mL reagent bottle. Tightly seal and cool to room temperature. When cool add 3 mL of reagent water. Mix thoroughly by shaking or rolling for 10 min and let it stand for at least 2 h. Keep the bottle sealed tightly.

6.6 Alumina--Neutral activity Super I, W200 series (ICN Life Sciences Group, No. 404583). To prepare for use, place 100 g of alumina into a 500-mL beaker and heat for approximately 16 h at 400 [deg]C. After heating transfer to a 500-mL reagent bottle. Tightly seal and cool to room temperature. When cool add 3 mL of reagent water. Mix thoroughly by shaking or rolling for 10 min and let it stand for at least 2 h. Keep the bottle sealed tightly.

6.7 Stock standard solutions (1.00 [micro]g/[micro]L)--Stock standard solutions can be prepared from pure standard materials or purchased as certified solutions.

6.7.1 Prepare stock standard solutions by accurately weighing about 0.0100 g of pure material. Dissolve the material in isooctane and dilute to volume in a 10-mL volumetric flask. Larger volumes can be used at the convenience of the analyst. When compound purity is assayed to be 96% or greater, the weight can be used without correction to calculate the concentration of the stock standard. Commercially prepared stock standards can be used at any concentration if they are certified by the manufacturer or by an independent source.

6.7.2 Transfer the stock standard solutions into Teflon-sealed screw-cap bottles. Store at 4 [deg]C and protect from light. Stock standard solutions should be checked frequently for signs of degradation or evaporation, especially just prior to preparing calibration standards from them.

6.7.3 Stock standard solutions must be replaced after six months, or sooner if comparison with check standards indicates a problem.

6.8 Quality control check sample concentrate--See Section 8.2.1.

7. Calibration

7.1 Establish gas chromatograph operating conditions equivalent to those given in Table 1. The gas chromatographic system can be calibrated using the external standard technique (Section 7.2) or the internal standard technique (Section 7.3).

7.2 External standard calibration procedure:

7.2.1 Prepared calibration standards at a minimum of three concentration levels for each parameter of interest by adding volumes of one or more stock standards to a volumetric flask and diluting to volume with isooctane. One of the external standards should be at a concentration near, but above, the MDL (Table 1) and the other concentrations should correspond to the expected range of concentrations found in real samples or should define the working range of the detector.

7.2.2 Using injections of 2 to 5 [micro]L, analyze each calibration standard according to Section 12 and tabulate peak height or area responses against the mass injected. The results can be used to prepare a calibration curve for each compound. Alternatively, if the ratio of response to amount injected (calibration factor) is a constant over the working range (<10% relative standard deviation, RSD), linearity through the origin can be assumed and the average ratio or calibration factor can be used in place of a calibration curve.

7.3.1 Prepare calibration standards at a minimum of three concentration levels for each parameter of interest by adding volumes of one or more stock standards to a volumetric flash. To each calibration standard, add a known constant amount of one or more internal standards, and dilute to volume with isooctane. One of the standards should be at a concentration near, but above, the MDL and the other concentrations should correspond to the expected range of concentrations found in real samples or should define the working range of the detector.

7.3.2 Using injections of 2 to 5 [micro]L, analyze each calibration standard according to Section 12 and tabulate peak height or area responses against concentration for each compound and internal standard. Calculate response factors (RF) for each compound using Equation 1.

RF = (As)(Cis (Ais)(Cs)

Equation 1 where:As=Response for the parameter to be measured.Ais=Response for the internal standard.Cis=Concentration of the internal standard ([micro]g/L).Cs=Concentration of the parameter to be measured ([micro]g/

L).

8. Quality Control

8.1.1 The analyst must make an initial, one-time, demonstration of the ability to generate acceptable accuracy and precision with this method. This ability is established as described in Section 8.2.

8.1.2 In recognition of advances that are occurring in chromatography, the analyst is permitted certain options (detailed in Sections 10.4, 11.1, and 12.1) to improve the separations or lower the cost of measurements. Each time such a modification is made to the method, the analyst is required to repeat the procedure in Section 8.2.

8.1.4 The laboratory must, on an ongoing basis, spike and analyze a minimum of 10% of all samples to monitor and evaluate laboratory data quality. This procedure is described in Section 8.3.

8.1.6 The laboratory must maintain performance records to document the quality of data that is generated. This procedure is described in Section 8.5.

8.2 To establish the ability to generate acceptable accuracy and precision, the analyst must perform the following operations.

8.2.1 A quality contrml (QC) check sample concentrate is required containing each parameter of interest at the following concentrations in acetone: butyl benzyl phthalate, 10 [micro]g/mL; bis(2-ethylhexyl) phthalate, 50 [micro]g/mL; di-n-octyl phthalate, 50 [micro]g/mL; any other phthlate, 25 [micro]g/mL. The QC check sample concentrate must be obtained from the U.S. Environmental Protection Agancy, Environmental Monitoring and Support Laboratory in Cincinnati, Ohio, if available. If not available from that source, the QC check sample concentrate must be obtained from another external source. If not available from either source above, the QC check sample concentrate must be prepared by the laboratory using stock standards prepared independently from those used for calibration.

8.2.2 Using a pipet, prepare QC check samples at the test concentrations shown in Table 2 by adding 1.00 mL of QC check sample concentrate to each of four 1-L aliquots of reagent water.

8.2.3 Analyze the well-mixed QC check samples according to the method beginning in Section 10.

8.2.4 Calculate the average recovery (X) in [micro]g/L, and the standard deviation of the recovery (s) in [micro]g/L, for each parameter using the four results.

8.2.5 For each parameter compare s and X with the corresponding acceptance criteria for precision and accuracy, respectively, found in Table 2. If s and X for all parameters of interest meet the acceptance criteria, the system performance is acceptable and analysis of actual samples can begin. If any individual s exceeds the precision limit or any individual X falls outside the range for accuracy, the system performance is unacceptable for that parameter. Locate and correct the source of the problem and repeat the test for all parameters of interest beginning with Section 8.2.2.

8.3.1 The concentration of the spike in the sample should be determined as follows:

8.3.1.2 If the concentration of a specific parameter in the sample is not being checked against a limit specific to that parameter, the spike should be at the test concentration in Section 8.2.2 or 1 to 5 times higher than the background concentration determined in Section 8.3.2, whichever concentration would be larger.

8.3.1.3 If it is impractical to determine background levels before spiking (e.g., maximum holding times will be exceeded), the spike concentration should be (1) the regulatory concentration limit, if any; or, if none (2) the larger of either 5 times higher than the expected background concentration or the test concentration in Section 8.2.2.

8.3.3 Compare the percent recovery (P) for each parameter with the corresponding QC acceptance criteria found in Table 2. These acceptance criteria were calculated to include an allowance for error in measurement of both the background and spike concentrations, assuming a spike to background ratio of 5:1. This error will be accounted for to the extent that the analyst's spike to background ratio approaches 5:1. \9\ If spiking was performed at a concentration lower than the test concentration in Section 8.2.2, the analyst must use either the QC acceptance criteria in Table 2, or optional QC acceptance criteria calculated for the specific spike concentration. To calculate optional acceptance criteria for the recovery of a parameter: (1) Calculate accuracy (X') using the equation in Table 3, substituting the spike concentration (T) for C; (2) calculate overall precision (S') using the equation in Table 3, substituting X' for X; (3) calculate the range for recovery at the spike concentration as (100 X'/T)2.44(100 S'/T)%. \9\

8.4 If any parameter fails the acceptance criteria for recovery in Section 8.3, a QC check standard containing each parameter that failed must be prepared and analyzed.

8.5 As part of the QC program for the laboratory, method accuracy for wastewater samples must be assessed and records must be maintained. After the analysis of five spiked wastewater samples as in Section 8.3, calculate the average percent recovery (P) and the standard deviation of the percent recovery (sp). Express the accuracy assessment as a percent recovery interval from P-2sp to P+2sp. If P=90% and sp=10%, for example, the accuracy interval is expressed as 70-110%. Update the accuracy assessment for each parameter on a regular basis (e.g. after each five to ten new accuracy measurements).

9. Sample Collection, Preservation, and Handling

9.1 Grab samples must be collected in glass containers. Conventional sampling practices \10\ should be followed, except that the bottle must not be prerinsed with sample before collection. Composite samples should be collected in refrigerated glass containers in accordance with the requirements of the program. Automatic sampling equipment must be as free as possible of Tygon tubing and other potential sources of contamination.

9.2 All samples must be iced or refrigerated at 4 [deg]C from the time of collection until extraction.

9.3 All samples must be extracted within 7 days of collection and completely analyzed within 40 days of extraction. \2\

10. Sample Extraction

10.1 Mark the water meniscus on the side of the sample bottle for later determination of sample volume. Pour the entire sample into a 2-L separatory funnel.

10.2 Add 60 mL of methylene chloride to the sample bottle, seal, and shake 30 s to rinse the inner surface. Transfer the solvent to the separatory funnel and extract the sample by shaking the funnel for 2 min. with periodic venting to release excess pressure. Allow the organic layer to separate from the water phase for a minimum of 10 min. If the emulsion interface between layers is more than one-third the volume of the solvent layer, the analyst must employ mechanical techniques to complete the phrase separation. The optimum technique depends upon the sample, but may include stirring, filtration of the emulsion through glass wool, centrifugation, or other physical methods. Collect the methylene chloride extract in a 250-mL Erlenmeyer flask.

10.3 Add a second 60-mL volume of methylene chloride to the sample bottle and repeat the extraction procedure a second time, combining the extracts in the Erlenmeyer flask. Perform a third extraction in the same manner.

10.4 Assemble a Kuderna-Danish (K-D) concentrator by attaching a 10-mL concentrator tube to a 500-mL evaporative flask. Other concentrator devices or techniques may be used in place of the K-D concentrator if the requirements of Section 8.2 are met.

10.5 Pour the combined extract through a solvent-rinsed drying column containing about 10 cm of anhydrous sodium sulfate, and collect the extract in the K-D concentrator. Rinse the Erlenmeyer flask and column with 20 to 30 mL of methylene chloride to complete the quantitative transfer.

10.6 Add one or two clean boiling chips to the evaporative flask and attach a three-ball Snyder column. Prewet the Snyder column by adding about 1 mL of methylene chloride to the top. Place the K-D apparatus on a hot water bath (60 to 65 [deg]C) so that the concentrator tube is partially immersed in the hot water, and the entire lower rounded surface of the flask is bathed with hot vapor. Adjust the vertical position of the apparatus and the water temperature as required to complete the concentration in 15 to 20 min. At the proper rate of distillation the balls of the column will actively chatter but the chambers will not flood with condensed solvent. When the apparent volume of liquid reaches 1 mL, remove the K-D apparatus and allow it to drain and cool for at least 10 min.

10.7 Increase the temperature of the hot water bath to about 80 [deg]C. Momentarily remove the Snyder column, add 50 mL of hexane and a new boiling chip, and reattach the Snyder column. Concentrate the extract as in Section 10.6, except use hexane to prewet the column. The elapsed time of concentration should be 5 to 10 min.

10.8 Remove the Snyder column and rinse the flask and its lower joint into the concentrator tube with 1 to 2 mL of hexane. A 5-mL syringe is recommended for this operation. Adjust the extract volume to 10 mL. Stopper the concentrator tube and store refrigerated if further processing will not be performed immediately. If the extract will be stored longer than two days, it should be transferred to a Teflon-sealed screw-cap vial. If the sample extract requires no further cleanup, proceed with gas chromatographic analysis (Section 12). If the sample requires further cleanup, proceed to Section 11.

10.9 Determine the original sample volume by refilling the sample bottle to the mark and transferring the liquid to a 1000-mL graduated cylinder. Record the sample volume to the nearest 5 mL.

11. Cleanup and Separation

11. Cleanup procedures may not be necessary for a relatively clean sample matrix. If particular circumstances demand the use of a cleanup procedure, the analyst may use either procedure below or any other appropriate procedure. However, the analyst first must demonstrate that the requirements of Section 8.2 can be met using the method as revised to incorporate the cleanup procedure.

11.2 If the entire extract is to be cleaned up by one of the following procedures, it must be concentrated to 2.0 mL. To the concentrator tube in Section 10.8, add a clean boiling chip and attach a two-ball micro-Snyder column. Prewet the column by adding about 0.5 mL of hexane to the top. Place the micro-K-D apparatus on a hot water bath (80 [deg]C) so that the concentrator tube is partially immersed in the hot water. Adjust the vertical position of the apparatus and the water temperature as required to complete the concentration in 5 to 10 min. At the proper rate of distillation the balls of the column will actively chatter but the chambers will not flood. When the apparent volume of liquid reaches about 0.5 mL, remove the K-D apparatus and allow it to drain and cool for at least 10 min. Remove the micro-Snyder column and rinse its lower joint into the concentrator tube with 0.2 mL of hexane. Adjust the final volume to 2.0 mL and proceed with one of the following cleanup procedures.

11.3 Florisil column cleanup for phthalate esters:

11.3.1 Place 10 g of Florisil into a chromatographic column. Tap the column to settle the Florisil and add 1 cm of anhydrous sodium sulfate to the top.

11.3.2 Preelute the column with 40 mL of hexane. The rate for all elutions should be about 2 mL/min. Discard the eluate and just prior to exposure of the sodium sulfate layer to the air, quantitatively transfer the 2-mL sample extract onto the column using an additional 2 mL of hexane to complete the transfer. Just prior to exposure of the sodium sulfate layer to the air, add 40 mL of hexane and continue the elution of the column. Discard this hexane eluate.

11.3.3 Next, elute the column with 100 mL of 20% ethyl ether in hexane (V/V) into a 500-mL K-D flask equipped with a 10-mL concentrator tube. Concentrate the collected fraction as in Section 10.6. No solvent exchange is necessary. Adjust the volume of the cleaned up extract to 10 mL in the concentrator tube and analyze by gas chromatography (Section 12).

11.4 Alumina column cleanup for phthalate esters:

11.4.1 Place 10 g of alumina into a chromatographic column. Tap the column to settle the alumina and add 1 cm of anhydrous sodium sulfate to the top.

11.4.2 Preelute the column with 40 mL of hexane. The rate for all elutions should be about 2 mL/min. Discard the eluate and just prior to exposure of the sodium sulfate layer to the air, quantitatively transfer the 2-mL sample extract onto the column using an additional 2 mL of hexane to complete the transfer. Just prior to exposure of the sodium sulfate layer to the air, add 35 mL of hexane and continue the elution of the column. Discard this hexane eluate.

11.4.3 Next, elute the column with 140 mL of 20% ethyl ether in hexane (V/V) into a 500-mL K-D flask equipped with a 10-mL concentrator type. Concentrate the collected fraction as in Section 10.6. No solvent exchange is necessary. Adjust the volume of the cleaned up extract to 10 mL in the concentrator tube and analyze by gas chromatography (Section 12).

12. Gas Chromatography

12.1 Table 1 summarizes the recommended operating conditions for the gas chromatograph. Included in this table are retention times and MDL that can be achieved under these conditions. Examples of the separations achieved by Column 1 are shown in Figures 1 and 2. Other packed or capillary (open-tubular) columns, chromatographic conditions, or detectors may be used if the requirements of Section 8.2 are met.

12.2 Calibrate the system daily as described in Section 7.

12.3 If the internal standard calibration procedure is being used, the internal staldard must be added to the sample extract and mixed thoroughly immediately before injection into the gas chromatograph.

12.4 Inject 2 to 5 [micro]L of the sample extract or standard into the gas-chromatograph using the solvent-flush technique. \11\ Smaller (1.0 [micro]L) volumes may be injected if automatic devices are employed. Record the volume injected to the nearest 0.05 [micro]L, and the resulting peak size in area or peak height units.

12.6 If the response for a peak exceeds the working range of the system, dilute the extract and reanalyze.

12.7 If the measurement of the peak response is prevented by the presence of interferences, further cleanup is required.

13. Calculations

13.1 Determine the concentration of individual compounds in the sample.

Equation 2 where:A=Amount of material injected (ng).Vi=Volume of extract injected ([micro]L).Vt=Volume of total extract ([micro]L).Vs=Volume of water extracted (mL).

Equation 3 where:As=Response for the parameter to be measured.Ais=Response for the internal standard.Is=Amount of internal standard added to each extract

([micro]g).Vo=Volume of water extracted (L).

13.2 Report results in [micro]g/L without correction for recovery data. All QC data obtained should be reported with the sample results.

14. Method Performance

14.1 The method detection limit (MDL) is defined as the minimum concentration of a substance that can be measured and reported with 99% confidence that the value is above zero. \1\ The MDL concentrations listed in Table 1 were obtained using reagent water. \12\ Similar results were achieved using representative wastewaters. The MDL actually achieved in a given analysis will vary depending on instrument sensitivity and matrix effects.

14.2 This method has been tested for linearity of spike recovery from reagent water and has been demonstrated to be applicable over the concentration range from 5 x MDL to 1000 x MDL with the following exceptions: dimethyl and diethyl phthalate recoveries at 1000 x MDL were low (70%); bis-2-ethylhexyl and di-n-octyl phthalate recoveries at 5 x MDL were low (60%). \12\

14.3 This method was tested by 16 laboratories using reagent water, drinking water, surface water, and three industrial wastewaters spiked at six concentrations over the range 0.7 to 106 [micro]g/L. \13\ Single operator precision, overall precision, and method accuracy were found to be directly related to the concentration of the parameter and essentially independent of the sample matrix. Linear equations to describe these relationships are presented in Table 3.

References

1. 40 CFR part 136, appendix B.

2. ``Determination of Phthalates in Industrial and Muncipal Wastewaters,'' EPA 600/4-81-063, National Technical Information Service, PB81-232167, Springfield, Virginia 22161, July 1981.

4. Giam, C.S., Chan, H.S., and Nef, G.S. ``Sensitive Method for Determination of Phthalate Ester Plasticizers in Open-Ocean Biota Samples,'' Analytical Chemistry, 47, 2225 (1975).

5. Giam, C.S., and Chan, H.S. ``Control of Blanks in the Analysis of Phthalates in Air and Ocean Biota Samples,'' U.S. National Bureau of Standards, Special Publication 442, pp. 701-708, 1976.

6. ``Carcinogens--Working with Carcinogens,'' Department of Health, Education, and Welfare, Public Health Service, Center for Disease Control, National Institute for Occupational Safety and Health, Publication No. 77-206, August 1977.

7. ``OSHA Safety and Health Standards, General Industry,'' (29 CFR part 1910), Occupational Safety and Health Administration, OSHA 2206 (Revised, January 1976).

8. ``Safety in Academic Chemistry Laboratories,'' American Chemical Society Publication, Committee on Chemical Safety, 3rd Edition, 1979.

9. Provost L.P., and Elder, R.S. ``Interpretation of Percent Recovery Data,'' American Laboratory, 15, 58-63 (1983). (The value 2.44 used in the equation in Section 8.3.3 is two times the value 1.22 derived in this report.)

10. ASTM Annual Book of Standards, Part 31, D3370-76. ``Standard Practices for Sampling Water,'' American Society for Testing and Materials, Philadelphia.

11. Burke, J.A. ``Gas Chromatography for Pesticide Residue Analysis; Some Practical Aspects,'' Journal of the Association of Official Analytical Chemists, 48, 1037 (1965).

12. ``Method Detection Limit and Analytical Curve Studies, EPA Methods 606, 607, and 608,'' Special letter report for EPA Contract 68-03-2606, U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory, Cincinnati, Ohio 45268, June 1980.

13. ``EPA Method Study 16 Method 606 (Phthalate Esters),'' EPA 600/4-84-056, National Technical Information Service, PB84-211275, Springfield, Virginia 22161, June 1984.

Table 1--Chromatographic Conditions and Method Detection Limits------------------------------------------------------------------------

Retention time (min) Method

---------------------------- detection

Parameter limit

Column 1 Column 2 ([micro]g/L)------------------------------------------------------------------------Dimethyl phthalate............ 2.03 0.95 0.29Diethyl phthalate............. 2.82 1.27 0.49Di-n-butyl phthalate.......... 8.65 3.50 0.36Butyl benzyl phthalate........ \a\ 6.94 \a\ 5.11 0.34Bis(2-ethylhexyl) phthalate... \a\ 8.92 \a\ 10.5 2.0Di-n-octyl phthalate.......... \a\ 16.2 \a\ 18.0 3.0------------------------------------------------------------------------Column 1 conditions: Supelcoport (100/120 mesh) coated with 1.5% SP-2250/

1.95% SP-2401 packed in a 1.8 m long x 4 mm ID glass column with 5%

methane/95% argon carrier gas at 60 mL/min flow rate. Column

temperature held isothermal at 180 [deg]C, except where otherwise

indicated.Column 2 conditions: Supelcoport (100/120 mesh) coated with 3% OV-1

packed in a 1.8 m long x 4 mm ID glass column with 5% methane/95%

argon carrier gas at 60 mL/min flow rate. Column temperature held

isothermal at 200 [deg]C, except where otherwise indicated.\a\ 220 [deg]C column temperature.

Table 2--QC Acceptance Criteria--Method 606----------------------------------------------------------------------------------------------------------------

Limit for Range for

Test conc. s X Range for

Parameter ([micro]g/ ([micro]g/ ([micro]g/ P, Ps

L) L) L) (percent)----------------------------------------------------------------------------------------------------------------Bis(2-ethylhexyl) phthalate...................................... 50 38.4 1.2-55.9 D-158Butyl benzyl phthalate........................................... 10 4.2 5.7-11.0 30-136Di-n-butyl phthalate............................................. 25 8.9 10.3-29.6 23-136Diethyl phthalate................................................ 25 9.0 1.9-33.4 D-149Dimethyl phathalate.............................................. 25 9.5 1.3-35.5 D-156Di-n-octyl phthalate............................................. 50 13.4 D-50.0 D-114----------------------------------------------------------------------------------------------------------------s=Standard deviation of four recovery measurements, in [micro]g/L (Section 8.2.4).X=Average recovery for four recovery measurements, in [micro]g/L (Section 8.2.4).P, Ps=Percent recovery measured (Section 8.3.2, Section 8.4.2).D=Detected; result must be greater than zero.

Note: These criteria are based directly upon the method performance data in Table 3. Where necessary, the limits

for recovery have been broadened to assure applicability of the limits to concentrations below those used to

develop Table 3.

Table 3--Method Accuracy and Precision as Functions of Concentration--Method 606----------------------------------------------------------------------------------------------------------------

Accuracy, as Single analyst Overall

Parameter recovery, X' precision, sr' precision, S'

[micro]g/L.S'=Expected interlaboratory standard deviation of measurements at an average concentration found of X, in

Method 607--Nitrosamines

1. Scope and Application

1.1 This method covers the determination of certain nitrosamines. The following parameters can be determined by this method: ------------------------------------------------------------------------

Parameter Storet No. CAS No.------------------------------------------------------------------------N-Nitrosodimethylamine........................ 34438 62-75-9N-Nitrosodiphenylamine........................ 34433 86-30-6N-Nitrosodi-n-propylamine..................... 34428 621-64-7------------------------------------------------------------------------

1.2 This is a gas chromatographic (GC) method applicable to the determination of the parameters listed above in municipal and industrial discharges as provided under 40 CFR 136.1. When this method is used to analyze unfamiliar samples for any or all of the compmunds above, compound identifications should be supported by at least one additional qualitative technique. This method describes analytical conditimns for a second gas chromatographic column that can be used to confirm measurements made with the primary column. Method 625 provides gas chromatograph/mass spectrometer (GC/MS) conditions appropriate for the qualitative and quantitative confirmation of results for N-nitrosodi-n-propylamine. In order to confirm the presence of N-nitrosodiphenylamine, the cleanup procedure specified in Section 11.3 or 11.4 must be used. In order to confirm the presence of N-nitrosodimethylamine by GC/MS, Column 1 of this method must be substituted for the column recommended in Method 625. Confirmation of these parameters using GC-high resolution mass spectrometry or a Thermal Energy Analyzer is also recommended. \1 2\

1.3 The method detection limit (MDL, defined in Section 14.1) \3\ for each parameter is listed in Table 1. The MDL for a specific wastewater may differ from those listed, depending upon the nature of interferences in the sample matrix.

2. Summary of Method

2.1 A measured volume of sample, approximately 1-L, is extracted with methylene chloride using a separatory funnel. The methylene chloride extract is washed with dilute hydrochloric acid to remove free amines, dried, and concentrated to a volume of 10 mL or less. After the extract has been exchanged to methanol, it is separated by gas chromatography and the parameters are then measured with a nitrogen-phosphorus detector. \4\

2.2 The method provides Florisil and alumina column cleanup procedures to separate diphenylamine from the nitrosamines and to aid in the elimination of interferences that may be encountered.

3. Interferences

3.1.1 Glassware must be scrupulously cleaned. \5\ Clean all glassware as soon as possible after use by rinsing with the last solvent used in it. Solvent rinsing should be followed by detergent washing with hot water, and rinses with tap water and distilled water. The glassware should then be drained dry, and heated in a muffle furnace at 400 [deg]C for 15 to 30 min. Solvent rinses with acetone and pesticide quality hexane may be substituted for the muffle furnace heating. Volumetric ware should not be heated in a muffle furnace. After drying and cooling, glassware should be sealed and stored in a clean environment to prevent any accumulation of dust or other contaminants. Store inverted or capped with aluminum foil.

3.1.2 The use of high purity reagents and solvents helps to minimize interference problems. Purification of solvents by distillation in all-glass systems may be required.

3.2 Matrix interferences may be caused by contaminants that are co-extracted from the sample. The extent of matrix interferences will vary considerably from source to source, depending upon the nature and diversity of the industrial complex or municipality being sampled. The cleanup procedures in Section 11 can be used to overcome many of these interferences, but unique samples may require additional cleanup approaches to achieve the MDL listed in Table 1.

3.3 N-Nitrosodiphenylamine is reported \6-9\ to undergo transnitrosation reactions. Care must be exercised in the heating or concentrating of solutions containing this compound in the presence of reactive amines.

3.4 The sensitive and selective Thermal Energy Analyzer and the reductive Hall detector may be used in place of the nitrogen-phosphorus detector when interferences are encountered. The Thermal Energy Analyzer offers the highest selectivity of the non-MS detectors.

4. Safety

4.2 These nitrosamines are known carcinogens, \13-17\ therefore, utmost care must be exercised in the handling of these materials. Nitrosamine reference standards and standard solutions should be handled and prepared in a ventilated glove box within a properly ventilated room.

5. Apparatus and Materials

5.1 Sampling equipment, for discrete or composite sampling.

5.1.2 Automatic sampler (optional)--The sampler must incorporate glass sample containers for the collection of a minimum of 250 mL of sample. Sample containers must be kept refrigerated at 4 [deg]C and protected from light during compositing. If the sampler uses a peristaltic pump, a minimum length of compressible silicone rubber tubing may be used. Before use, however, the compressible tubing should be thoroughly rinsed with methanol, followed by repeated rinsings with distilled water to minimize the potential for contamination of the sample. An integrating flowmeter is required to collect flow proportional composites.

5.2 Glassware (All specifications are suggested. Catalog numbers are included for illustration only.):

5.2.1 Separatory funnels--2-L and 250-mL, with Teflon stopcock.

5.2.2 Drying column--Chromatographic column, approximately 400 mm long x 19 mm ID, with coarse frit filter disc.

5.2.3 Concentrator tube, Kuderna-Danish--10-mL, graduated (Kontes K-570050-1025 or equivalent). Calibration must be checked at the volumes employed in the test. Ground glass stopper is used to prevent evaporation of extracts.

5.2.4 Evaporative flask, Kuderna-Danish--500-mL (Kontes K-570001-0500 or equivalent). Attach to concentrator tube with springs.

5.2.5 Snyder column, Kuderna-Danish--Three-ball macro (Kontes K-503000-0121 or equivalent).

5.2.6 Snyder column, Kuderna-Danish--Two-ball micro (Kontes K-569001-0219 or equivalent).

5.2.7 Vials--10 to 15-mL, amber glass, with Teflon-lined screw cap.

5.2.8 Chromatographic column--Approximately 400 mm long x 22 mm ID, with Teflon stopcock and coarse frit filter disc at bottom (Kontes K-420540-0234 or equivalent), for use in Florisil column cleanup procedure.

5.2.9 Chromatographic column--Approximately 300 mm long x 10 mm ID, with Teflon stopcock and coarse frit filter disc at bottom (Kontes K-420540-0213 or equivalent), for use in alumina column cleanup procedure.

5.3 Boiling chips--Approximately 10/40 mesh. Heat to 400 [deg]C for 30 min or Soxhlet extract with methylene chloride.

5.4 Water bath--Heated, with concentric ring cover, capable of temperature control (2 [deg]C). The bath should be used in a hood.

5.5 Balance--Analytical, capable of accurately weighing 0.0001 g.

5.6.1 Column 1--1.8 m long x 4 mm ID glass, packed with 10% Carbowax 20 M/2% KOH on Chromosorb W-AW (80/100 mesh) or equivalent. This column was used to develop the method performance statements in Section 14. Guidelines for the use of alternate column packings are provided in Section 12.2.

5.6.2 Column 2--1.8 m long x 4 mm ID glass, packed with 10% SP-2250 on Supel-coport (100/120 mesh) or equivalent.

5.6.3 Detector--Nitrogen-phosphorus, reductive Hall, or Thermal Energy Analyzer detector. \1 2\ These detectors have proven effective in the analysis of wastewaters for the parameters listed in the scope (Section 1.1). A nitrogen-phosphorus detector was used to develop the method performance statements in Section 14. Guidelines for the use of alternate detectors are provided in Section 12.2.

6. Reagents

6.1 Reagent water--Reagent water is defined as a water in which an interferent is not observed at the MDL of the parameters of interest.

6.2 Sodium hydroxide solution (10 N)--Dissolve 40 g of NaOH (ACS) in reagent water and dilute to 100 ml.

6.3 Sodium thiosulfate--(ACS) Granular.

6.4 Sulfuric acid (1+1)--Slowly, add 50 mL of H2SO4 (ACS, sp. gr. 1.84) to 50 mL of reagent water.

6.5 Sodium sulfate--(ACS) Granular, anhydrous. Purify by heating at 400 [deg]C for 4 h in a shallow tray.

6.6 Hydrochloric acid (1+9)--Add one volume of concentrated HCl (ACS) to nine volumes of reagent water.

6.7 Acetone, methanol, methylene chloride, pentane--Pesticide quality or equivalent.

6.8 Ethyl ether--Nanograde, redistilled in glass if necessary.

6.8.1 Ethyl ether must be shown to be free of peroxides before it is used as indicated by EM Laboratories Quant test strips. (Available from Scientific Products Co., Cat No. P1126-8, and other suppliers.)

6.8.2 Procedures recommended for removal of peroxides are provided with the test strips. After cleanup, 20 mL of ethyl alcohol preservative must be added to each liter of ether.

6.9 Florisil--PR grade (60/100 mesh). Purchase activated at 1250 [deg]F and store in the dark in glass containers with ground glass stoppers or foil-lined screw caps. Before use, activate each batch at least 16 h at 130 [deg]C in a foil-covered glass container and allow to cool.

6.10 Alumina--Basic activity Super I, W200 series (ICN Life Sciences Group, No. 404571, or equivalent). To prepare for use, place 100 g of alumina into a 500-mL reagent bottle and add 2 mL of reagent water. Mix the alumina preparation thoroughly by shaking or rolling for 10 min and let it stand for at least 2 h. The preparation should be homogeneous before use. Keep the bottle sealed tightly to ensure proper activity.

6.11 Stock standard solutions (1.00 [micro]g/[micro]L)--Stock standard solutions can be prepared from pure standard materials or purchased as certified solutions.

6.11.3 Stock standard solutions must be replaced after six months, or sooner if comparison with check standards indicates a problem.

6.12 Quality control check sample concentrate--See Section 8.2.1.

7. Calibration

7.1 Establish gas chromatographic operating conditions equivalent to those given in Table 1. The gas chromatographic system can be calibrated using the external standard technique (Section 7.2) or the internal standard technique (Section 7.3).

7.2 External standard calibration procedure:

7.2.1 Prepare calibration standards at a minimum of three concentration levels for each parameter of interest by adding volumes of one or more stock standards to a volumetric flask and diluting to volume with methanol. One of the external standards should be at a concentration near, but above, the MDL (Table 1) and the other concentrations should correspond to the expected range of concentrations found in real samples or should define the working range of the detector.

7.3.1 Prepare calibration standards at a minimum of three concentration levels for each parameter of interest by adding volumes of one or more stock standards to a volumetric flask. To each calibration standard, add a known constant amount of one or more internal standards, and dilute to volume with methanol. One of the standards should be at a concentration near, but above, the MDL and the other concentrations should correspond to the expected range of concentrations found in real samples or should define the working range of the detector.

RF = (As)(Cis (Ais)(Cs)

Equation 1 where:As=Response for the parameter to be measured.Ais=Response for the internal standard.Cis=Concentration of the internal standard ([micro]g/L).Cs=Concentration of the parameter to be measured ([micro]g/

L).

8. Quality Control

8.1.1 The analyst must make an initial, one-time, demonstration of the ability to generate acceptable accuracy and precision with this method. This ability is established as described in Section 8.2.

8.1.2 In recognition of advances that are occurring in chromatography, the analyst is permitted certain options (detailed in Sections 10.4, 11.1, and 12.2) to improve the separations or lower the cost of measurements. Each time such a modification is made to the method, the analyst is required to repeat the procedure in Section 8.2.

8.1.4 The laboratory must, on an ongoing basis, spike and analyze a minimum of 10% of all samples to monitor and evaluate laboratory data quality. This procedure is described in Section 8.3.

8.1.6 The laboratory must maintain performance records to document the quality of data that is generated. This procedure is described in Section 8.5.

8.2 To establish the ability to generate acceptable accuracy and precision, the analyst must perform the following operations.

8.2.1 A quality control (QC) check sample concentrate is required containing each parameter of interest at a concentration of 20 [micro]g/mL in methanol. The QC check sample concentrate must be obtained from the U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory in Cincinnati, Ohio, if available. If not available from that source, the QC check sample concentrate must be obtained from another external source. If not available from either source above, the QC check sample concentrate must be prepared by the laboratory using stock standards prepared independently from those used for calibration.

8.2.2 Using a pipet, prepare QC check samples at a concentration of 20 [micro]g/L by adding 1.00 mL of QC check sample concentrate to each of four 1-L aliquots of reagent water.

8.2.3 Analyze the well-mixed QC check samples according to the method beginning in Section 10.

8.2.4 Calculate the average recovery (X) in [micro]g/L, and the standard deviation of the recovery (s) in [micro]g/L, for each parameter using the four results.

8.2.5 For each parameter compare s and X with the corresponding acceptance criteria for precision and accuracy, respectively, found in Table 2. If s and X for all parameters of interest meet the acceptance criteria, the system performance is acceptable and analysis of actual samples can begin. If any individual s exceeds the precision limit or any individual X falls outside the range for accuracy, the system performance is unacceptable for that parameter. Locate and correct the source of the problem and repeat the test for all parameters of interest beginning with Section 8.2.2.

8.3.1 The concentration of the spike in the sample should be determined as follows:

8.3.1.3 If it is impractical to determine background levels before spiking (e.g., maximum holding times will be exceeded), the spike concentration should be (1) the regulatory concentration limit, if any; or, if none (2) the larger of either 5 times higher than the expected background concentration or 20 [micro]g/L.

8.3.3 Compare the percent recovery (P) for each parameter with the corresponding QC acceptance criteria found in Table 2. These acceptance criteria were caluclated to include an allowance for error in measurement of both the background and spike concentrations, assuming a spike to background ratio of 5:1. This error will be accounted for to the extent that the analyst's spike to background ratio approaches 5:1. \18\ If spiking was performed at a concentration lower than 20 [micro]g/L, the analyst must use either the QC acceptance criteria in Table 2, or optional QC acceptance criteria caluclated for the specific spike concentration. To calculate optional acceptance crtieria for the recovery of a parameter: (1) Calculate accuracy (X') using the equation in Table 3, substituting the spike concentration (T) for C; (2) calculate overall precision (S') using the equation in Table 3, substituting X' for X; (3) calculate the range for recovery at the spike concentration as (100 X'/T) 2.44(100 S'/T)%. \18\

8.4 If any parameter fails the acceptance criteria for recovery in Section 8.3, a QC check standard containing each parameter that failed must be prepared and analyzed.

8.5 As part of the QC program for the laboratory, method accuracy for wastewater samples must be assessed and records must be maintained. After the analysis of five spiked wastewater samples as in Section 8.3, calculate the average percent recovery (P) and the standard deviation of the percent recovery (sp). Express the accuracy assessment as a percent recovery interval from P-2sp to P+2sp. If P=90% and sp=10%, for example, the accuracy interval is expressed as 70-110%. Update the accuracy assessment for each parameter on a regular basis (e.g. after each five to ten new accuracy measurements).

9. Sample Collection, Preservation, and Handling

9.1 Grab samples must be collected in glass containers. Conventional sampling practices \19\ should be followed, except that the bottle must not be prerinsed with sample before collection. Composite samples should be collected in refrigerated glass containers in accordance with the requirements of the program. Automatic sampling equipment must be as free as possible of Tygon tubing and other potential sources of contamination.

9.2 All samples must be iced or refrigerated at 4 [deg]C from the time of collection until extraction. Fill the sample bottles and, if residual chlorine is present, add 80 mg of sodium thiosulfate per liter of sample and mix well. EPA Methods 330.4 and 330.5 may be used for measurement of residual chlorine. \20\ Field test kits are available for this purpose. If N-nitrosodiphenylamine is to be determined, adjust the sample pH to 7 to 10 with sodium hydroxide solution or sulfuric acid.

9.3 All samples must be extracted within 7 days of collection and completely analyzed within 40 days of extraction. \4\

9.4 Nitrosamines are known to be light sensitive. \7\ Samples should be stored in amber or foil-wrapped bottles in order to minimize photolytic decomposition.

10. Sample Extraction

10.1 Mark the water meniscus on the side of the sample bottle for later determination of sample volume. Pour the entire sample into a 2-L separatory funnel. Check the pH of the sample with wide-range pH paper and adjust to within the range of 5 to 9 with sodium hydroxide solution or sulfuric acid.

10.2 Add 60 mL of methylene chloride to the sample bottle, seal, and shake 30 s to rinse the inner surface. Transfer the solvent to the separatory funnel and extract the sample by shaking the funnel for 2 min with periodic venting to release excess pressure. Allow the organic layer to separate from the water phase for a minimum of 10 min. If the emulsion interface between layers is more than one-third the volume of the solvent layer, the analyst must employ mechanical techniques to complete the phase separation. The optimum technique depends upon the sample, but may include stirring, filtration of the emulsion through glass wool, centrifugation, or other physical methods. Collect the methylene chloride extract in a 250-mL Erlenmeyer flask.

10.4 Assemble a Kuderna-Danish (K-D) concentrator by attaching a 10-mL concentrator tube to a 500-mL evaporative flask. Other concentration devices or techniques may be used in place of the K-D concentrator if the requirements of Section 8.2 are met.

10.5 Add 10 mL of hydrochloric acid to the combined extracts and shake for 2 min. Allow the layers to separate. Pour the combined extract through a solvent-rinsed drying column containing about 10 cm of anhydrous sodium sulfate, and collect the extract in the K-D concentrator. Rinse the Erlenmeyer flask and column with 20 to 30 mL of methylene chloride to complete the quantitative transfer.

10.7 Remove the Snyder column and rinse the flask and its lower joint into the concentrator tube with 1 to 2 mL of methylene chloride. A 5-mL syringe is recommended for this operation. Stopper the concentrator tube and store refrigerated if further processing will not be performed immediately. If the extract will be stored longer than two days, it should be transferred to a Teflon-sealed screw-cap vial. If N-nitrosodiphenylamine is to be measured by gas chromatography, the analyst must first use a cleanup column to eliminate diphenylamine interference (Section 11). If N-nitrosodiphenylamine is of no interest, the analyst may proceed directly with gas chromatographic analysis (Section 12).

10.8 Determine the original sample volume by refilling the sample bottle to the mark and transferring the liquid to a 1000-mL graduated cylinder. Record the sample volume to the nearest 5 mL.

11. Cleanup and Separation

11.1 Cleanup procedures may not be necessary for a relatively clean sample matrix. If particular circumstances demand the use of a cleanup procedure, the analyst may use either procedure below or any other appropriate procedure. However, the analyst first must demonstrate that the requirements of Section 8.2 can be met using the method as revised to incorporate the cleanup procedure. Diphenylamine, if present in the original sample extract, must be separated from the nitrosamines if N-nitrosodiphenylamine is to be determined by this method.

11.2 If the entire extract is to be cleaned up by one of the following procedures, it must be concentrated to 2.0 mL. To the concentrator tube in Section 10.7, add a clean boiling chip and attach a two-ball micro-Snyder column. Prewet the column by adding about 0.5 mL of methylene chloride to the top. Place the micr-K-D apparatus on a hot water bath (60 to 65 [deg]C) so that the concentrator tube is partially immersed in the hot water. Adjust the vertical position of the apparatus and the water temperature as required to complete the concentration in 5 to 10 min. At the proper rate of distillation the balls of the column will actively chatter but the chambers will not flood. When the apparent volume of liquid reaches about 0.5 mL, remove the K-D apparatus and allow it to drain and cool for at least 10 min. Remove the micro-Snyder column and rinse its lower joint into the concentrator tube with 0.2 mL of methylene chloride. Adjust the final volume to 2.0 mL and proceed with one of the following cleanup procedures.

11.3 Florisil column cleanup for nitrosamines:

11.3.1 Place 22 g of activated Florisil into a 22-mm ID chromatographic column. Tap the column to settle the Florisil and add about 5 mm of anhydrous sodium sulfate to the top.

11.3.2 Preelute the column with 40 mL of ethyl ether/pentane (15+85)(V/V). Discard the eluate and just prior to exposure of the sodium sulfate layer to the air, quantitatively transfer the 2-mL sample extract onto the column using an additional 2 mL of pentane to complete the transfer.

11.3.3 Elute the column with 90 mL of ethyl ether/pentane (15+85)(V/V) and discard the eluate. This fraction will contain the diphenylamine, if it is present in the extract.

11.3.4 Next, elute the column with 100 mL of acetone/ethyl ether (5+95)(V/V) into a 500-mL K-D flask equipped with a 10-mL concentrator tube. This fraction will contain all of the nitrosamines listed in the scope of the method.

11.3.5 Add 15 mL of methanol to the collected fraction and concentrate as in Section 10.6, except use pentane to prewet the column and set the water bath at 70 to 75 [deg]C. When the apparatus is cool, remove the Snyder column and rinse the flask and its lower joint into the concentrator tube with 1 to 2 mL of pentane. Analyze by gas chromatography (Section 12).

11.4 Alumina column cleanup for nitrosamines:

11.4.1 Place 12 g of the alumina preparation (Section 6.10) into a 10-mm ID chromatographic column. Tap the column to settle the alumina and add 1 to 2 cm of anhydrous sodium sulfate to the top.

11.4.2 Preelute the column with 10 mL of ethyl ether/pentane (3+7)(V/V). Discard the eluate (about 2 mL) and just prior to exposure of the sodium sulfate layer to the air, quantitatively transfer the 2 mL sample extract onto the column using an additional 2 mL of pentane to complete the transfer.

11.4.3 Just prior to exposure of the sodium sulfate layer to the air, add 70 mL of ethyl ether/pentane (3+7)(V/V). Discard the first 10 mL of eluate. Collect the remainder of the eluate in a 500-mL K-D flask equipped with a 10 mL concentrator tube. This fraction contains N-nitrosodiphenylamine and probably a small amount of N-nitrosodi-n-propylamine.

11.4.4 Next, elute the column with 60 mL of ethyl ether/pentane (1+1)(V/V), collecting the eluate in a second K-D flask equipped with a 10-mL concentrator tube. Add 15 mL of methanol to the K-D flask. This fraction will contain N-nitrosodimethylamine, most of the N-nitrosodi-n-propylamine and any diphenylamine that is present.

11.4.5 Concentrate both fractions as in Section 10.6, except use pentane to prewet the column. When the apparatus is cool, remove the Snyder column and rinse the flask and its lower joint into the concentrator tube with 1 to 2 mL of pentane. Analyze the fractions by gas chromatography (Section 12).

12. Gas Chromatography

12.1 N-nitrosodiphenylamine completely reacts to form diphenylamine at the normal operating temperatures of a GC injection port (200 to 250 [deg]C). Thus, N-nitrosodiphenylamine is chromatographed and detected as diphenylamine. Accurate determination depends on removal of diphenylamine that may be present in the original extract prior to GC analysis (See Section 11).

12.2 Table 1 summarizes the recommended operating conditions for the gas chromatograph. Included in this table are retention times and MDL that can be achieved under these conditions. Examples of the separations achieved by Column 1 are shown in Figures 1 and 2. Other packed or capillary (open-tubular) columns, chromatographic conditions, or detectors may be used if the requirements of Section 8.2 are met.

12.3 Calibrate the system daily as described in Section 7.

12.4 If the extract has not been subjected to one of the cleanup procedures in Section 11, it is necessary to exchange the solvent from methylene chloride to methanol before the thermionic detector can be used. To a 1 to 10-mL volume of methylene chloride extract in a concentrator tube, add 2 mL of methanol and a clean boiling chip. Attach a two-ball micro-Snyder column to the concentrator tube. Prewet the column by adding about 0.5 mL of methylene chloride to the top. Place the micro-K-D apparatus on a boiling (100 [deg]C) water bath so that the concentrator tube is partially immersed in the hot water. Adjust the vertical position of the apparatus and the water temperature as required to complete the concentration in 5 to 10 min. At the proper rate of distillation the balls of the column will actively chatter but the chambers will not flood. When the apparent volume of liquid reaches about 0.5 mL, remove the K-D apparatus and allow it to drain and cool for at least 10 min. Remove the micro-Snyder column and rinse its lower joint into the concentrator tube with 0.2 mL of methanol. Adjust the final volume to 2.0 mL.

12.5 If the internal standard calibration procedure is being used, the internal standard must be added to the sample extract and mixed thoroughly immediately before injection into the gas chromatograph.

12.6 Inject 2 to 5 [micro]L of the sample extract or standard into the gas chromatograph using the solvent-flush technique. \21\ Smaller (1.0 [micro]L) volumes may be injected if automatic devices are employed. Record the volume injected to the nearest 0.05 [micro]L, and the resulting peak size in area or peak height units.

12.7 Identify the parameters in the sample by comparing the retention times of the peaks in the sample chromatogram with those of the peaks in standard chromatograms. The width of the retention time window used to make identifications should be based upon measurements of actual retention time variations of standards over the course of a day. Three times the standard deviation of a retention time for a compound can be used to calculate a suggested window size; however, the experience of the analyst should weigh heavily in the interpretation of chromatograms.

12.8 If the response for a peak exceeds the working range of the system, dilute the extract and reanalyze.

12.9 If the measurement of the peak response is prevented by the presence of interferences, further cleanup is required.

13. Calculations

13.1 Determine the concentration of individual compounds in the sample.

Equation 2 where:A=Amount of material injected (ng).Vi=Volume of extract injected ([micro]L).Vt=Volume of total extract ([micro]L).Vs=Volume of water extracted (mL).

Equation 3 where:As=Response for the parameter to be measured.Ais=Response for the internal standard.Is=Amount of internal standard added to each extract

([micro]g).Vo=Volume of water extracted (L).

13.2 Report results in [micro]g/L without correction for recovery data. All QC data obtained should be reported with the sample results.

14. Method Performance

14.1 The method detection limit (MDL) is defined as the minimum concentration of a substance that can be measured and reported with 99% confidence that the value is above zero. \3\ The MDL concentrations listed in Table 1 were obtained using reagent water. \22\ Similar results were achieved using representative wastewaters. The MDL actually achieved in a given analysis will vary depending on instrument sensitivity and matrix effects.

14.2 This method has been tested for linearity of spike recovery from reagent water and has been demonstrated to be applicable over the concentration range from 4 x MDL to 1000 x MDL. \22\

14.3 This method was tested by 17 laboratories using reagent water, drinking water, surface water, and three industrial wastewaters spiked at six concentrations over the range 0.8 to 55 [micro]g/L. \23\ Single operator precision, overall precision, and method accuracy were found to be directly related to the concentration of the parameter and essentially independent of the sample matrix. Linear equations to describe these relationships are presented in Table 3.

References

1. Fine, D.H., Lieb, D., and Rufeh, R. ``Principle of Operation of the Thermal Energy Analyzer for the Trace Analysis of Volatile and Non-volatile N-nitroso Compounds,'' Journal of Chromatography, 107, 351 (1975).

2. Fine, D.H., Hoffman, F., Rounbehler, D.P., and Belcher, N.M. ``Analysis of N-nitroso Compounds by Combined High Performance Liquid Chromatography and Thermal Energy Analysis,'' Walker, E.A., Bogovski, P. and Griciute, L., Editors, N-nitroso Compounds--Analysis and Formation, Lyon, International Agency for Research on Cancer (IARC Scientific Publications No. 14), pp. 43-50 (1976).

3. 40 CFR part 136, appendix B.

4. ``Determination of Nitrosamines in Industrial and Municipal Wastewaters,'' EPA 600/4-82-016, National Technical Information Service, PB82-199621, Springfield, Virginia 22161, April 1982.

5. ASTM Annual Book of Standards, Part 31, D3694-78. ``Standard Practices for Preparation of Sample Containers and for Preservation of Organic Constituents,'' American Society for Testing and Materials, Philadelphia.

6. Buglass, A.J., Challis, B.C., and Osborn, M.R. ``Transnitrosation and Decomposition of Nitrosamines,'' Bogovski, P. and Walker, E.A., Editors, N-nitroso Compounds in the Environment, Lyon, International Agency for Research on Cancer (IARC Scientific Publication No. 9), pp. 94-100 (1974).

7. Burgess, E.M., and Lavanish, J.M. ``Photochemical Decomposition of N-nitrosamines,'' Tetrahedon Letters, 1221 (1964)

8. Druckrey, H., Preussmann, R., Ivankovic, S., and Schmahl, D. ``Organotrope Carcinogene Wirkungen bei 65 Verschiedenen N-NitrosoVerbindungen an BD-Ratten,'' Z. Krebsforsch., 69, 103 (1967).

9. Fiddler, W. ``The Occurrence and Determination of N-nitroso Compounds,'' Toxicol. Appl. Pharmacol., 31, 352 (1975).

10. ``Carcinogens--Working With Carcinogens,'' Department of Health, Education, and Welfare, Public Health Service, Center for Disease Control, National Institute for Occupational Safety and Health, Publication No. 77-206, August 1977.

11. ``OSHA Safety and Health Standards, General Industry,'' (29 CFR Part 1910), Occupational Safety and Health Administration, OSHA 2206 (Revised, January 1976).

12. ``Safety in Academic Chemistry Laboratories,'' American Chemical Society Publication, Committee on Chemical Safety, 3rd Edition, 1979.

13. Lijinsky, W. ``How Nitrosamines Cause Cancer,'' New Scientist, 73, 216 (1977).

14. Mirvish, S.S. ``N-Nitroso compounds: Their Chemical and in vivo Formation and Possible Importance as Environmental Carcinogens,'' J. Toxicol. Environ. Health, 3, 1267 (1977).

15. ``Reconnaissance of Environmental Levels of Nitrosamines in the Central United States,'' EPA-330/1-77-001, National Enforcement Investigations Center, U.S. Environmental Protection Agency (1977).

16. ``Atmospheric Nitrosamine Assessment Report,'' Office of Air Quality Planning and Standards, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina (1976).

17. ``Scientific and Technical Assessment Report on Nitrosamines,'' EPA-660/6-7-001, Office of Research and Development, U.S. Environmental Protection Agency (1976).

18. Provost, L.P., and Elder, R.S. ``Interpretation of Percent Recovery Data,'' American Laboratory, 15, 58-63 (1983). (The value 2.44 used in the equation in Section 8.3.3 is two times the value of 1.22 derived in this report.)

19. ASTM Annual Book of Standards, Part 31, D3370-76. ``Standard Practices for Sampling Water,'' American Society for Testing and Materials, Philadelphia.

20. ``Methods 330.4 (Titrimetric, DPD-FAS) and 330.5 (Spectrophotometric, DPD) for Chlorine, Total Residual,'' Methods for Chemical Analysis of Water and Wastes, EPA-600/4-79-020, U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory, Cincinnati, Ohio 45268, March 1979.

21. Burke, J. A. ``Gas Chromatography for Pesticide Residue Analysis; Some Practical Aspects,'' Journal of the Association of Official Analytical Chemists, 48, 1037 (1965).

22. ``Method Detection Limit and Analytical Curve Studies EPA Methods 606, 607, and 608,'' Special letter report for EPA Contract 68-03-2606, U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory, Cincinnati, Ohio 45268, June 1980.

23. ``EPA Method Study 17 Method 607--Nitrosamines,'' EPA 600/4-84-051, National Technical Information Service, PB84-207646, Springfield, Virginia 22161, June 1984.

Table 1--Chromatographic Conditions and Method Detection Limits------------------------------------------------------------------------

Retention time (min) Method

-------------------------- detection

Parameter limit

Column 1 Column 2 ([micro]g/

L)------------------------------------------------------------------------N-Nitrosodimethylamine........... 4.1 0.88 0.15N-Nitrosodi-n-propylamine........ 12.1 4.2 .46

N-Nitrosodiphenylamine \a\....... \b\ 12.8 \c\ 6.4 .81------------------------------------------------------------------------Column 1 conditions: Chromosorb W-AW (80/100 mesh) coated with 10%

Carbowax 20 M/2% KOH packed in a 1.8 m long x 4mm ID glass column with

helium carrier gas at 40 mL/min flow rate. Column temperature held

isothermal at 110 [deg]C, except where otherwise indicated.Column 2 conditions: Supelcoport (100/120 mesh) coated with 10% SP-2250

packed in a 1.8 m long x 4 mm ID glass column with helium carrier gas

at 40 mL/min flow rate. Column temperature held isothermal at 120

[deg]C, except where otherwise indicated.\a\ Measured as diphenylamine.\b\ 220 [deg]C column temperature.\c\ 210 [deg]C column temperature.

Table 2--QC Acceptance Criteria--Method 607----------------------------------------------------------------------------------------------------------------

Test conc. Limit for s Range for X Range for

Parameter ([micro]g/ ([micro]g/ ([micro]g/ P, Ps

L) L) L) (percent)----------------------------------------------------------------------------------------------------------------N-Nitrosodimethylamine...................................... 20 3.4 4.6-20.0 13-109N-Nitrosodiphenyl........................................... 20 6.1 2.1-24.5 D-139N-Nitrosodi-n-propylamine................................... 20 5.7 11.5-26.8 45-146----------------------------------------------------------------------------------------------------------------s=Standard deviation for four recovery measurements, in [micro]g/L (Section 8.2.4).X=Average recovery for four recovery measurements, in [micro]g/L (Section 8.2.4).P, Ps=Percent recovery measured (Section 8.3.2, Section 8.4.2).D=Detected; result must be greater than zero.

Note: These criteria are based directly upon the method performance data in Table 3. Where necessary, the limits

for recovery have been broadened to assure applicability of the limits to concentrations below those used to

develop Table 3.

Table 3--Method Accuracy and Precision as Functions of Concentration--Method 607----------------------------------------------------------------------------------------------------------------

Accuracy, as Single analyst Overall

Parameter recovery, X' precision, sr' precision, S'

[micro]g/L.S'=Expected interlaboratory standard deviation of measurements at an average concentration found of X, in

Method 608--Organochlorine Pesticides and PCBs

1. Scope and Application

1.1 This method covers the determination of certain organochlorine pesticides and PCBs. The following parameters can be determined by this method: ------------------------------------------------------------------------

Parameter STORET No. CAS No.------------------------------------------------------------------------Aldrin...................................... 39330 309-00-2[alpha]-BHC................................. 39337 319-84-6[beta]-BHC.................................. 39338 319-85-7[delta]-BHC................................. 34259 319-86-8[gamma]-BHC................................. 39340 58-89-9Chlordane................................... 39350 57-74-94,4'-DDD.................................... 39310 72-54-84,4'-DDE.................................... 39320 72-55-94,4'-DDT.................................... 39300 50-29-3Dieldrin.................................... 39380 60-57-1Endosulfan I................................ 34361 959-98-8Endosulfan II............................... 34356 33212-65-9Endosulfan sulfate.......................... 34351 1031-07-8Eldrin...................................... 39390 72-20-8Endrin aldehyde............................. 34366 7421-93-4Heptachlor.................................. 39410 76-44-8Heptachlor epoxide.......................... 39420 1024-57-3Toxaphene................................... 39400 8001-35-2PCB-1016.................................... 34671 12674-11-2PCB-1221.................................... 39488 1104-28-2PCB-1232.................................... 39492 11141-16-5PCB-1242.................................... 39496 53469-21-9PCB-1248.................................... 39500 12672-29-6PCB-1254.................................... 39504 11097-69-1PCB-1260.................................... 39508 11096-82-5------------------------------------------------------------------------

1.4 The sample extraction and concentration steps in this method are essentially the same as in Methods 606, 609, 611, and 612. Thus, a single sample may be extracted to measure the parameters included in the scope of each of these methods. When cleanup is required, the concentration levels must be high enough to permit selecting aliquots, as necessary, to apply appropriate cleanup procedures. The analyst is allowed the latitude, under Section 12, to select chromatographic conditions appropriate for the simultaneous measurement of combinations of these parameters.

2. Summary of Method

2.1 A measured volume of sample, approximately 1-L, is extracted with methylene chloride using a separatory funnel. The methylene chloride extract is dried and exchanged to hexane during concentration to a volume of 10 mL or less. The extract is separated by gas chromatography and the parameters are then measured with an electron capture detector. \2\

2.2 The method provides a Florisil column cleanup procedure and an elemental sulfur removal procedure to aid in the elimination of interferences that may be encountered.

3. Interferences

3.1.1 Glassware must be scrupulously cleaned. \3\ Clean all glassware as soon as possible after use by rinsing with the last solvent used in it. Solvent rinsing should be followed by detergent washing with hot water, and rinses with tap water and distilled water. The glassware should then be drained dry, and heated in a muffle furnace at 400 [deg]C for 15 to 30 min. Some thermally stable materials, such as PCBs, may not be eliminated by this treatment. Solvent rinses with acetone and pesticide quality hexane may be substituted for the muffle furnace heating. Thorough rinsing with such solvents usually eliminates PCB interference. Volumetric ware should not be heated in a muffle furnace. After drying and cooling, glassware should be sealed and stored in a clean environment to prevent any accumulation of dust or other contaminants. Store inverted or capped with aluminum foil.

3.1.2 The use of high purity reagents and solvents helps to minimize interference problems. Purification of solvents by distillation in all-glass systems may be required.

3.2 Interferences by phthalate esters can pose a major problem in pesticide analysis when using the electron capture detector. These compounds generally appear in the chromatogram as large late eluting peaks, especially in the 15 and 50% fractions from Florisil. Common flexible plastics contain varying amounts of phthalates. These phthalates are easily extracted or leached from such materials during laboratory operations. Cross contamination of clean glassware routinely occurs when plastics are handled during extraction steps, especially when solvent-wetted surfaces are handled. Interferences from phthalates can best be minimized by avoiding the use of plastics in the laboratory. Exhaustive cleanup of reagents and glassware may be required to eliminate background phthalate contamination. \4 5\ The interferences from phthalate esters can be avoided by using a microcoulometric or electrolytic conductivity detector.

4. Safety

4.2 The following parameters covered by this method have been tentatively classified as known or suspected, human or mammalian carcinogens: 4,4'-DDT, 4,4'-DDD, the BHCs, and the PCBs. Primary standards of these toxic compounds should be prepared in a hood. A NIOSH/MESA approved toxic gas respirator should be worn when the analyst handles high concentrations of these toxic compounds.

5. Apparatus and Materials

5.1 Sampling equipment, for discrete or composite sampling.

5.1.2 Automatic sampler (optional)--The sampler must incorporate glass sample containers for the collection of a minimum of 250 mL of sample. Sample containers must be kept refrigerated at 4 [deg]C and protected from light during composting. If the sampler uses a peristaltic pump, a minimum length of compressible silicone rubber tubing may be used. Before use, however, the compressible tubing should be thoroughly rinsed with methanol, followed by repeated rinsings with distilled water to minimize the potential for contamination of the sample. An integrating flow meter is required to collect flow proportional composites.

5.2. Glassware (All specifications are suggested. Catalog numbers are included for illustration only.):

5.2.1 Separatory funnel--2-L, with Teflon stopcock.

5.2.2 Drying column--Chromatographic column, approximately 400 mm long x 19 mm ID, with coarse frit filter disc.

5.2.3 Chromatographic column--400 mm long x 22 mm ID, with Teflon stopcock and coarse frit filter disc (Kontes K-42054 or equivalent).

5.2.5 Evaporative flask, Kuderna-Danish--500-mL (Kontes K-570001-0500 or equivalent). Attach to concentrator tube with springs.

5.2.6 Snyder column, Kuderna/Danish--Three-ball macro (Kontes K-503000-0121 or equivalent).

5.2.7 Vials--10 to 15-mL, amber glass, with Teflon-lined screw cap.

5.3 Boiling chips--Approximately 10/40 mesh. Heat to 400 [deg]C for 30 min or Soxhlet extract with methylene chloride.

5.4 Water bath--Heated, with concentric ring cover, capable of temperature control (2 [deg]C). The bath should be used in a hood.

5.5 Balance--Analytical, capable of accurately weighing 0.0001 g.

5.6 Gas chromatograph--An analytical system complete with gas chromatograph suitable for on-column injection and all required accessories including syringes, analytical columns, gases, detector, and strip- chart recorder. A data system is recommended for measuring peak areas.

5.6.1 Column 1--1.8 m long x 4 mm ID glass, packed with 1.5% SP-2250/1.95% SP-2401 on Supelcoport (100/120 mesh) or equivalent. This column was used to develop the method performance statements in Section 14. Guidelines for the use of alternate column packings are provided in Section 12.1.

5.6.2 Column 2--1.8 m long x 4 mm ID glass, packed with 3% OV-1 on Supelcoport (100/120 mesh) or equivalent.

6. Reagents

6.1 Reagent water--Reagent water is defined as a water in which an interferent is not observed at the MDL of the parameters of interest.

6.2 Sodium hydroxide solution (10 N)--Dissolve 40 g of NaOH (ACS) in reagent water and dilute to 100 mL.

6.3 Sodium thiosulfate--(ACS) Granular.

6.4 Sulfuric acid (1+1)--Slowly, add 50 mL to H2SO4 (ACS, sp. gr. 1.84) to 50 mL of reagent water.

6.5 Acetone, hexane, isooctane, methylene chloride--Pesticide quality or equivalent.

6.6 Ethyl ether--Nanograde, redistilled in glass if necessary.

6.6.1 Ethyl ether must be shown to be free of peroxides before it is used as indicated by EM Laboratories Quant test strips. (Available from Scientific Products Co., Cat. No. P1126-8, and other suppliers.)

6.6.2 Procedures recommended for removal of peroxides are provided with the test strips. After cleanup, 20 mL of ethyl alcohol preservative must be added to each liter of ether.

6.7 Sodium sulfate--(ACS) Granular, anhydrous. Purify by heating at 400 [deg]C for 4 h in a shallow tray.

6.8 Florisil--PR grade (60/100 mesh). Purchase activated at 1250 [deg]F and store in the dark in glass containers with ground glass stoppers or foil-lined screw caps. Before use, activate each batch at least 16 h at 130 [deg]C in a foil-covered glass container and allow to cool.

6.9 Mercury--Triple distilled.

6.10 Copper powder--Activated.

6.11 Stock standard solutions (1.00 [micro]g/[micro]L)--Stock standard solutions can be prepared from pure standard materials or purchased as certified solutions.

6.11.1 Prepare stock standard solutions by accurately weighing about 0.0100 g of pure material. Dissolve the material in isooctane and dilute to volume in a 10-mL volumetric flask. Larger volumes can be used at the convenience of the analyst. When compound purity is assayed to be 96% or greater, the weight can be used without correction to calculate the concentration of the stock standard. Commercially prepared stock standards can be used at any concentration if they are certified by the manufacturer or by an independent source.

6.11.3 Stock standard solutions must be replaced after six months, or sooner if comparison with check standards indicates a problem.

6.12 Quality control check sample concentrate--See Section 8.2.1.

7. Calibration

7.2 External standard calibration procedure:

7.2.1 Prepare calibration standards at a minimum of three concentration levels for each parameter of interest by adding volumes of one or more stock standards to a volumetric flask and diluting to volume with isooctane. One of the external standards should be at a concentration near, but above, the MDL (Table 1) and the other concentrations should correspond to the expected range of concentrations found in real samples or should define the working range of the detector.

7.3.1 Prepare calibration standards at a minimum of three concentration levels for each parameter of interest by adding volumes of one or more stock standards to a volumetric flask. To each calibration standard, add a known constant amount of one or more internal standards, and dilute to volume with isooctane. One of the standards should be at a concentration near, but above, the MDL and the other concentrations should correspond to the expected range of concentrations found in real samples or should define the working range of the detector.

Equation 1where:As=Response for the parameter to be measured.Ais=Response for the internal standard.Cis=Concentration of the internal standard ([micro]g/L).Cs=Concentration of the parameter to be measured ([micro]g/

L).

7.4 The working calibration curve, calibration factor, or RF must be verified on each working day by the measurement of one or more calibration standards. If the response for any parameter varies from the predicted response by more than 15%, the test must be repeated using a fresh calibration standard. Alternatively, a new calibration curve must be prepared for that compound.

7.5 The cleanup procedure in Section 11 utilizes Florisil column chromatography. Florisil from different batches or sources may vary in adsorptive capacity. To standardize the amount of Florisil which is used, the use of lauric acid value \9\ is suggested. The referenced procedure determines the adsorption from hexane solution of lauric acid (mg) per g of Florisil. The amount of Florisil to be used for each column is calculated by dividing 110 by this ratio and multiplying by 20 g.

8. Quality Control

8.1.1 The analyst must make an initial, one-time, demonstration of the ability to generate acceptable accuracy and precision with this method. This ability is established as described in Section 8.2.

8.1.4 The laboratory must, on an ongoing basis, spike and analyze a minimum of 10% of all samples to monitor and evaluate laboratory data quality. This procedure is described in Section 8.3.

8.1.6 The laboratory must maintain performance records to document the quality of data that is generated. This procedure is described in Section 8.5.

8.2 To establish the ability to generate acceptable accuracy and precision, the analyst must perform the following operations.

8.2.1 A quality control (QC) check sample concentrate is required containing each single-component parameter of interest at the following concentrations in acetone: 4,4'-DDD, 10 [micro]g/mL; 4,4'-DDT, 10 [micro]g/mL; endosulfan II, 10 [micro]g/mL; endosulfan sulfate, 10 [micro]g/mL; endrin, 10 [micro]g/mL; any other single-component pesticide, 2 [micro]g/mL. If this method is only to be used to analyze for PCBs, chlordane, or toxaphene, the QC check sample concentrate should contain the most representative multicomponent parameter at a concentration of 50 [micro]g/mL in acetone. The QC check sample concentrate must be obtained from the U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory in Cincinnati, Ohio, if available. If not available from that source, the QC check sample concentrate must be obtained from another external source. If not available from either source above, the QC check sample concentrate must be prepared by the laboratory using stock standards prepared independently from those used for calibration.

8.2.2 Using a pipet, prepare QC check samples at the test concentrations shown in Table 3 by adding 1.00 mL of QC check sample concentrate to each of four 1-L aliquots of reagent water.

8.2.3 Analyze the well-mixed QC check samples according to the method beginning in Section 10.

8.2.4 Calculate the average recovery (X) in [micro]g/mL; and the standard deviation of the recovery (s) in [micro]g/mL, for each parameter using the four results.

8.2.5 For each parameter compare s and X with the corresponding acceptance criteria for precision and accuracy, respectively, found in Table 3. If s and X for all parameters of interest meet the acceptance criteria, the system performance is acceptable and analysis of actual samples can begin. If any individual s exceeds the precision limit or any individual X falls outside the range for accuracy, the system performance is unacceptable for that parameter.

Note: The large number of parameters in Table 3 present a substantial probability that one or more will fail at least one of the acceptance criteria when all parameters are analyzed.

8.2.6 When one or more of the parameters tested fail at least one of the acceptance criteria, the analyst must proceed according to Section 8.2.6.1 or 8.2.6.2.

8.2.6.1 Locate and correct the source of the problem and repeat the test for all parameters of interest beginning with Section 8.2.2.

8.3.1 The concentration of the spike in the sample should be determined as follows:

8.3.1.3 If it is impractical to determine background levels before spiking (e.g., maximum holding times will be exceeded), the spike concentration should be (1) the regulatory concentration limit, if any; or, if none (2) the larger of either 5 times higher than the expected background concentration or the test concentration in Section 8.2.2.

8.3.3 Compare the percent recovery (P) for each parameter with the corresponding QC acceptance criteria found in Table 3. These acceptance criteria were calculated to include an allowance for error in measurement of both the background and spike concentrations, assuming a spike to background ratio of 5:1. This error will be accounted for to the extent that the analyst's spike to background ratio approaches 5:1. \10\ If spiking was performed at a concentration lower than the test concentration in Section 8.2.2, the analyst must use either the QC acceptance criteria in Table 3, or optional QC acceptance criteria calculated for the specific spike concentration. To calculate optional acceptance criteria for the recovery of a parameter: (1) Calculate accuracy (X') using the equation in Table 4, substituting the spike concentration (T) for C; (2) calculate overall precision (S') using the equation in Table 4, substituting X' for X; (3) calculate the range for recovery at the spike concentration as (100 X'/T)2.44(100 S'/T)%. \10\

8.4 If any parameter fails the acceptance criteria for recovery in Section 8.3, a QC check standard containing each parameter that failed must be prepared and analyzed.

Note: The frequency for the required analysis of a QC check standard will depend upon the number of parameters being simultaneously tested, the complexity of the sample matrix, and the performance of the laboratory. If the entire list of parameters in Table 3 must be measured in the sample in Section 8.3, the probability that the analysis of a QC check standard will be required is high. In this case the QC check standard should be routinely analyzed with the spike sample.

8.4.2 Analyze the QC check standards to determine the concentration measured (A) of each parameter. Calculate each percent recovery (Ps) as 100 (A/T)%, where T is the true value of the standard concentration.

8.5 As part of the QC program for the laboratory, method accuracy for wastewater samples must be assessed and records must be maintained. After the analysis of five spiked wastewater samples as in Section 8.3, calculate the average percent recovery (P) and the standard deviation of the percent recovery (sp). Express the accuracy assessment as a percent recovery interval from P-2 sp to P+2 sp. If P=90% and sp=10%, for example, the accuracy interval is expressed as 70-110%. Update the accuracy assessment for each parameter on a regular basis (e.g. after each five to ten new accuracy measurements).

9. Sample Collection, Preservation, and Handling

9.1 Grab samples must be collected in glass containers. Conventional sampling practices \11\ should be followed, except that the bottle must not be prerinsed with sample before collection. Composite samples should be collected in refrigerated glass containers in accordance with the requirements of the program. Automatic sampling equipment must be as free as possible of Tygon tubing and other potential sources of contamination.

9.2 All samples must be iced or refrigerated at 4 [deg]C from the time of collection until extraction. If the samples will not be extracted within 72 h of collection, the sample should be adjusted to a pH range of 5.0 to 9.0 with sodium hydroxide solution or sulfuric acid. Record the volume of acid or base used. If aldrin is to be determined, add sodium thiosulfate when residual chlorine is present. EPA Methods 330.4 and 330.5 may be used for measurement of residual chlorine. \12\ Field test kits are available for this purpose.

9.3 All samples must be extracted within 7 days of collection and completely analyzed within 40 days of extraction. \2\

10. Sample Extraction

10.1 Mark the water meniscus on the side of the sample bottle for later determination of sample volume. Pour the entire sample into a 2-L separatory funnel.

10.2 Add 60 mL of methylene chloride to the sample bottle, seal, and shake 30 s to rinse the inner surface. Transfer the solvent to the separatory funnel and extract the sample by shaking the funnel for 2 min. with periodic venting to release excess pressure. Allow the organic layer to separate from the water phase for a minimum of 10 min. If the emulsion interface between layers is more than one-third the volume of the solvent layer, the analyst must employ mechanical techniques to complete the phase separation. The optium technique depends upon the sample, but may include stirring, filtration of the emulsion through glass wool, centrifugation, or other physical methods. Collect the methylene chloride extract in a 250-mL Erlenmeyer flask.

10.7 Increase the temperature of the hot water bath to about 80 [deg]C. Momeltarily remove the Snyder column, add 50 mL of hexane and a new boiling chip, and reattach the Snyder column. Concentrate the extract as in Section 10.6, except use hexane to prewet the column. The elapsed time of concentration should be 5 to 10 min.

10.8 Remove the Snyder column and rinse the flask and its lower joint into the concentrator tube with 1 to 2 mL of hexane. A 5-mL syringe is recommended for this operation. Stopper the concentrator tube and store refrigerated if further processing will not be performed immediately. If the extract will be stored longer than two days, it should be transferred to a Teflon-sealed screw-cap vial. If the sample extract requires no further cleanup, proceed with gas chromatographic analysis (Section 12). If the sample requires further cleanup, proceed to Section 11.

10.9 Determine the original sample volume by refilling the sample bottle to the mark and transferring the liquid to a 1000-mL graduated cylinder. Record the sample volume to the nearest 5 mL.

11. Cleanup and Separation

11.1 Cleanup procedures may not be necessary for a relatively clean sample matrix. If particular circumstances demand the use of a cleanup procedure, the analyst may use either procedure below or any other appropriate procedure. However, the analyst first must demonstrate that the requirements of Section 8.2 can be met using the method as revised to incorporate the cleanup procedure. The Florisil column allows for a select fractionation of the compounds and will eliminate polar interferences. Elemental sulfur, which interferes with the electron capture gas chromatography of certain pesticides, can be removed by the technique described in Section 11.3.

11.2 Florisil column cleanup:

11.2.1 Place a weight of Florisil (nominally 20 g) predetermined by calibration (Section 7.5), into a chromatographic column. Tap the column to settle the Florisil and add 1 to 2 cm of anhydrous sodium sulfate to the top.

11.2.2 Add 60 mL of hexane to wet and rinse the sodium sulfate and Florisil. Just prior to exposure of the sodium sulfate layer to the air, stop the elution of the hexane by closing the stopcock on the chromatographic column. Discard the eluate.

11.2.3 Adjust the sample extract volume to 10 mL with hexane and transfer it from the K-D concentrator tube onto the column. Rinse the tube twice with 1 to 2 mL of hexane, adding each rinse to the column.

11.2.4 Place a 500-mL K-D flask and clean concentrator tube under the chromatographic column. Drain the column into the flask until the sodium sulfate layer is nearly exposed. Elute the column with 200 mL of 6% ethyl ether in hexane (V/V) (Fraction 1) at a rate of about 5 mL/min. Remove the K-D flask and set it aside for later concentration. Elute the column again, using 200 mL of 15% ethyl ether in hexane (V/V) (Fraction 2), into a second K-D flask. Perform the third elution using 200 mL of 50% ethyl ether in hexane (V/V) (Fraction 3). The elution patterns for the pesticides and PCBs are shown in Table 2.

11.2.5 Concentrate the fractions as in Section 10.6, except use hexane to prewet the column and set the water bath at about 85 [deg]C. When the apparatus is cool, remove the Snyder column and rinse the flask and its lower joint into the concentrator tube with hexane. Adjust the volume of each fraction to 10 mL with hexane and analyze by gas chromatography (Section 12).

11.3 Elemental sulfur will usually elute entirely in Fraction 1 of the Florisil column cleanup. To remove sulfur interference from this fraction or the original extract, pipet 1.00 mL of the concentrated extract into a clean concentrator tube or Teflon-sealed vial. Add one to three drops of mercury and seal. \13\ Agitate the contents of the vial for 15 to 30 s. Prolonged shaking (2 h) may be required. If so, this may be accomplished with a reciprocal shaker. Alternatively, activated copper powder may be used for sulfur removal. \14\ Analyze by gas chromatography.

12. Gas Chromatography

12.1 Table 1 summarizes the recommended operating conditions for the gas chromatograph. Included in this table are retention times and MDL that can be achieved under these conditions. Examples of the separations achieved by Column 1 are shown in Figures 1 to 10. Other packed or capillary (open-tubular) columns, chromatographic conditions, or detectors may be used if the requirements of Section 8.2 are met.

12.2 Calibrate the system daily as described in Section 7.

12.3 If the internal standard calibration procedure is being used, the internal standard must be added to the sample extract and mixed thoroughly immediately before injection into the gas chromatograph.

12.4 Inject 2 to 5 [micro]L of the sample extract or standard into the gas chromatograph using the solvent-flush technique. \15\ Smaller (1.0 uL) volumes may be injected if automatic devices are employed. Record the volume injected to the nearest 0.05 [micro]L, the total extract volume, and the resulting peak size in area or peak height units.

12.6 If the response for a peak exceeds the working range of the system, dilute the extract and reanalyze.

12.7 If the measurement of the peak response is prevented by the presence of interferences, further cleanup is required.

13. Calculations

13.1 Determine the concentration of individual compounds in the sample.

Equation 2 where:A=Amount of material injected (ng).Vi=Volume of extract injected ([micro]L).Vt=Volume of total extract ([micro]L).Vs=Volume of water extracted (mL).

Equation 3 where:As=Response for the parameter to be measured.Ais=Response for the internal standard.Is=Amount of internal standard added to each extract

([micro]g).Vo=Volume of water extracted (L).

13.2 When it is apparent that two or more PCB (Aroclor) mixtures are present, the Webb and McCall procedure \16\ may be used to identify and quantify the Aroclors.

13.3 For multicomponent mixtures (chlordane, toxaphene, and PCBs) match retention times of peaks in the standards with peaks in the sample. Quantitate every identifiable peak unless interference with individual peaks persist after cleanup. Add peak height or peak area of each identified peak in the chromatogram. Calculate as total response in the sample versus total response in the standard.

13.4 Report results in [micro]g/L without correction for recovery data. All QC data obtained should be reported with the sample results.

14. Method Performance

14.1 The method detection limit (MDL) is defined as the minimum concentration of a substance that can be measured and reported with 99% confidence that the value is above zero. \1\ The MDL concentrations listed in Table 1 were obtained using reagent water. \17\ Similar results were achieved using representative wastewaters. The MDL actually achieved in a given analysis will vary depending on instrument sensitivity and matrix effects.

14.2 This method has been tested for linearity of spike recovery from reagent water and has been demonstrated to be applicable over the concentration range from 4xMDL to 1000xMDL with the following exceptions: Chlordane recovery at 4xMDL was low (60%); Toxaphene recovery was demonstrated linear over the range of 10xMDL to 1000xMDL. \17\

14.3 This method was tested by 20 laboratories using reagent water, drinking water, surface water, and three industrial wastewaters spiked at six concentrations. \18\ Concentrations used in the study ranged from 0.5 to 30 [micro]g/L for single-component pesticides and from 8.5 to 400 [micro]g/L for multicomponent parameters. Single operator precision, overall precision, and method accuracy were found to be directly related to the concentration of the parameter and essentially independent of the sample matrix. Linear equations to describe these relationships are presented in Table 4.

References

1. 40 CFR part 136, appendix B.

2. ``Determination of Pesticides and PCBs in Industrial and Municipal Wastewaters,'' EPA 600/4-82-023, National Technical Information Service, PB82-214222, Springfield, Virginia 22161, April 1982.

4. Giam, C.S., Chan, H.S., and Nef, G.S., ``Sensitive Method for Determination of Phthalate Ester Plasticizers in Open-Ocean Biota Samples,'' Analytical Chemistry, 47, 2225 (1975).

5. Giam, C.S., Chan, H.S. ``Control of Blanks in the Analysis of Phthalates in Air and Ocean Biota Samples,'' U.S. National Bureau of Standards, Special Publication 442, pp. 701-708, 1976.

6. ``Carcinogens--Working With Carcinogens,'' Department of Health, Education, and Welfare, Public Health Service, Center for Disease Control, National Institute for Occupational Safety and Health, Publication No. 77-206, August 1977.

7. ``OSHA Safety and Health Standards, General Industry,'' (29 CFR part 1910), Occupational Safety and Health Administration, OSHA 2206 (Revised, January 1976).

8. ``Safety in Academic Chemistry Laboratories,'' American Chemical Society Publication, Committee on Chemical Safety, 3rd Edition, 1979.

9. Mills, P.A. ``Variation of Florisil Activity: Simple Method for Measuring Absorbent Capacity and Its Use in Standardizing Florisil Columns,'' Journal of the Association of Official Analytical Chemists, 51, 29, (1968).

10. Provost, L.P., and Elder, R.S. ``Interpretation of Percent Recovery Data,'' American Laboratory, 15, 58-63 (1983). (The value 2.44 used in the equation in Section 8.3.3 is two times the value 1.22 derived in this report.)

11. ASTM Annual Book of Standards, Part 31, D3370-76. ``Standard Practices for Sampling Water,'' American Society for Testing and Materials, Philadelphia.

12. ``Methods 330.4 (Titrimetric, DPD-FAS) and 330.5 (Spectrophotometric, DPD) for Chlorine, Total Residual,'' Methods for Chemical Analysis of Water and Wastes, EPA-600/4-79-020, U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory, Cincinnati, Ohio 45268, March 1979.

13. Goerlitz, D.F., and Law, L.M. Bulletin for Environmental Contamination and Toxicology, 6, 9 (1971).

14. ``Manual of Analytical Methods for the Analysis of Pesticides in Human and Environmental Samples,'' EPA-600/8-80-038, U.S. Environmental Protection Agency, Health Effects Research Laboratory, Research Triangle Park, North Carolina.

15. Burke, J.A. ``Gas Chromatography for Pesticide Residue Analysis; Some Practical Aspects,'' Journal of the Association of Official Analytical Chemists, 48, 1037 (1965).

16. Webb, R.G., and McCall, A.C. ``Quantitative PCB Standards for Election Capture Gas Chromatography,'' Journal of Chromatographic Science, 11, 366 (1973).

17. ``Method Detection Limit and Analytical Curve Studies, EPA Methods 606, 607, and 608,'' Special letter report for EPA Contract 68-03-2606, U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory, Cincinnati, Ohio 45268, June 1980.

18. ``EPA Method Study 18 Method 608--Organochlorine Pesticides and PCBs,'' EPA 600/4-84-061, National Technical Information Service, PB84-211358, Springfield, Virginia 22161, June 1984.

Table 1--Chromatographic Conditions and Method Detection Limits------------------------------------------------------------------------

Retention time (min) Method

-------------------------- detection

Parameter limit

Col. 1 Col. 2 ([micro]g/L)------------------------------------------------------------------------[alpha]-BHC.................... 1.35 1.82 0.003[gamma]-BHC.................... 1.70 2.13 0.004[beta]-BHC..................... 1.90 1.97 0.006Heptachlor..................... 2.00 3.35 0.003[delta]-BHC.................... 2.15 2.20 0.009Aldrin......................... 2.40 4.10 0.004Heptachlor epoxide............. 3.50 5.00 0.083Endosulfan I................... 4.50 6.20 0.0144,4'-DDE....................... 5.13 7.15 0.004Dieldrin....................... 5.45 7.23 0.002Endrin......................... 6.55 8.10 0.006

4,4'-DDD....................... 7.83 9.08 0.011Endosulfan II.................. 8.00 8.28 0.0044,4'-DDT....................... 9.40 11.75 0.012Endrin aldehyde................ 11.82 9.30 0.023Endosulfan sulfate............. 14.22 10.70 0.066Chlordane...................... mr mr 0.014Toxaphene...................... mr mr 0.24PCB-1016....................... mr mr ndPCB-1221....................... mr mr ndPCB-1232....................... mt mr ndPCB-1242....................... mr mr 0.065PCB-1248....................... mr mr ndPCB-1254....................... mr mr ndPCB-1260....................... mr mr nd------------------------------------------------------------------------Column 1 conditions: Supelcoport (100/120 mesh) coated with 1.5% SP-2250/

1.95% SP-2401 packed in a 1.8 m long x 4 mm ID glass column with 5%

methane/95% argon carrier gas at 60 mL/min flow rate. Column

temperature held isothermal at 200 [deg]C, except for PCB-1016 through

PCB-1248, should be measured at 160 [deg]C.Column 2 conditions: Supelcoport (100/120 mesh) coated with 3% OV-1

packed in a 1.8 m long x 4 mm ID glass column with 5% methane/95%

argon carrier gas at 60 mL/min flow rate. Column temperature held

isothermal at 200 [deg]C for the pesticides; at 140 [deg]C for PCB-

1221 and 1232; and at 170 [deg]C for PCB-1016 and 1242 to 1268.mr = Multiple peak response. See Figures 2 thru 10.nd = Not determined.

Table 2--Distribution of Chlorinated Pesticides and PCBs into Florisil

Column Fractions 2------------------------------------------------------------------------

Percent recovery by fraction \a\

Parameter --------------------------------------

1 2 3------------------------------------------------------------------------Aldrin........................... 100[alpha]-BHC...................... 100[beta]-BHC....................... 97[delta]-BHC...................... 98[gamma]-BHC...................... 100Chlordane........................ 1004,4'-DDD......................... 994,4'-DDE......................... 984,4'-DDT......................... 100Dieldrin......................... 0 100Endosulfan I..................... 37 64Endosulfan II.................... 0 7 91Endosulfan sulfate............... 0 0 106Endrin........................... 4 96Endrin aldehyde.................. 0 68 26Heptachlor....................... 100Heptachlor epoxide............... 100Toxaphene........................ 96PCB-1016......................... 97PCB-1221......................... 97PCB-1232......................... 95 4PCB-1242......................... 97PCB-1248......................... 103PCB-1254......................... 90PCB-1260......................... 95------------------------------------------------------------------------\a\ Eluant composition:

Fraction 1-6% ethyl ether in hexane.

Fraction 2-15% ethyl ether in hexane.

Fraction 3-50% ethyl ether in hexane.

Table 3--QC Acceptance Criteria--Method 608----------------------------------------------------------------------------------------------------------------

Range for

Test conc. Limit for s X Range for

Parameter ([micro]g/ ([micro]g/L) ([micro]g/ P, Ps(%)

L) L)----------------------------------------------------------------------------------------------------------------Aldrin...................................................... 2.0 0.42 1.08-2.24 42-122[alpha]-BHC................................................. 2.0 0.48 0.98-2.44 37-134[beta]-BHC.................................................. 2.0 0.64 0.78-2.60 17-147[delta]-BHC................................................. 2.0 0.72 1.01-2.37 19-140[gamma]-BHC................................................. 2.0 0.46 0.86-2.32 32-127

Chlordane................................................... 50 10.0 27.6-54.3 45-1194,4''-DDD................................................... 10 2.8 4.8-12.6 31-1414,4''-DDE................................................... 2.0 0.55 1.08-2.60 30-1454,4'-DDT.................................................... 10 3.6 4.6-13.7 25-160Dieldrin.................................................... 2.0 0.76 1.15-2.49 36-146Endosulfan I................................................ 2.0 0.49 1.14-2.82 45-153Endosulfan II............................................... 10 6.1 2.2-17.1 D-202Endosulfan Sulfate.......................................... 10 2.7 3.8-13.2 26-144Endrin...................................................... 10 3.7 5.1-12.6 30-147Heptachlor.................................................. 2.0 0.40 0.86-2.00 34-111Heptachlor epoxide.......................................... 2.0 0.41 1.13-2.63 37-142Toxaphene................................................... 50.0 12.7 27.8-55.6 41-126PCB-1016.................................................... 50 10.0 30.5-51.5 50-114PCB-1221.................................................... 50 24.4 22.1-75.2 15-178PCB-1232.................................................... 50 17.9 14.0-98.5 10-215PCB-1242.................................................... 50 12.2 24.8-69.6 39-150PCB-1248.................................................... 50 15.9 29.0-70.2 38-158PCB-1254.................................................... 50 13.8 22.2-57.9 29-131PCB-1260.................................................... 50 10.4 18.7-54.9 8-127----------------------------------------------------------------------------------------------------------------s = Standard deviation of four recovery measurements, in [micro]g/L (Section 8.2.4).X = Average recovery for four recovery measurements, in [micro]g/L (Section 8.2.4).P, Ps = Percent recovery measured (Section 8.3.2, Section 8.4.2).D = Detected; result must be greater than zero.

Note: These criteria are based directly upon the method performance data in Table 4. Where necessary, the limits

for recovery have been broadened to assure applicability of the limits to concentrations below those used to

develop Table 4.

Table 4--Method Accuracy and Precision as Functions of Concentration--Method 608----------------------------------------------------------------------------------------------------------------

Accuracy, as Single analyst

Parameter recovery, X' precision, sr' Overall precision,

([micro]g/L) ([micro]g/L) S' ([micro]g/L)----------------------------------------------------------------------------------------------------------------Aldrin.............................................. 0.81C+0.04 0.16X-0.04 0.20X-0.01[alpha]-BHC......................................... 0.84C+0.03 0.13X+0.04 0.23X-0.00[beta]-BHC.......................................... 0.81C+0.07 0.22X-0.02 0.33X-0.05[delta]-BHC......................................... 0.81C+0.07 0.18X+0.09 0.25X+0.03[gamma]-BHC......................................... 0.82C-0.05 0.12X+0.06 0.22X+0.04Chlordane........................................... 0.82C-0.04 0.13X+0.13 0.18X+0.184,4'-DDD............................................ 0.84C+0.30 0.20X-0.18 0.27X-0.144,4'-DDE............................................ 0.85C+0.14 0.13X+0.06 0.28X-0.094,4'-DDT............................................ 0.93C-0.13 0.17X+0.39 0.31X-0.21Dieldrin............................................ 0.90C+0.02 0.12X+0.19 0.16X+0.16Endosulfan I........................................ 0.97C+0.04 0.10X+0.07 0.18X+0.08Endosulfan II....................................... 0.93C+0.34 0.41X--0.65 0.47X-0.20Endosulfan Sulfate.................................. 0.89C-0.37 0.13X+0.33 0.24X+0.35Endrin.............................................. 0.89C-0.04 0.20X+0.25 0.24X+0.25Heptachlor.......................................... 0.69C+0.04 0.06X+0.13 0.16X+0.08Heptachlor epoxide.................................. 0.89C+0.10 0.18X-0.11 0.25X-0.08Toxaphene........................................... 0.80C+1.74 0.09X+3.20 0.20X+0.22PCB-1016............................................ 0.81C+0.50 0.13X+0.15 0.15X+0.45PCB-1221............................................ 0.96C+0.65 0.29X-0.76 0.35X-0.62PCB-1232............................................ 0.91C+10.79 0.21X-1.93 0.31X+3.50PCB-1242............................................ 0.93C+0.70 0.11X+1.40 0.21X+1.52PCB-1248............................................ 0.97C+1.06 0.17X+0.41 0.25X-0.37PCB-1254............................................ 0.76C+2.07 0.15X+1.66 0.17X+3.62PCB-1260............................................ 0.66C+3.76 0.22X-2.37 0.39X-4.86----------------------------------------------------------------------------------------------------------------X' = Expected recovery for one or more measurements of a sample containing a concentration of C, in [micro]g/L.sr' = Expected single analyst standard deviation of measurements at an average concentration found of X, in

[micro]g/L.S' = Expected interlaboratory standard deviation of measurements at an average concentration found of X, in

[micro]g/L.C = True value for the concentration, in [micro]g/L.X = Average recovery found for measurements of samples containing a concentration of C, in [micro]g/L. [GRAPHIC(S) NOT AVAILABLE IN TIFF FORMAT] [GRAPHIC(S) NOT AVAILABLE IN TIFF FORMAT] [GRAPHIC(S) NOT AVAILABLE IN TIFF FORMAT] [GRAPHIC(S) NOT AVAILABLE IN TIFF FORMAT] [GRAPHIC(S) NOT AVAILABLE IN TIFF FORMAT] [GRAPHIC(S) NOT AVAILABLE IN TIFF FORMAT] [GRAPHIC(S) NOT AVAILABLE IN TIFF FORMAT] [GRAPHIC(S) NOT AVAILABLE IN TIFF FORMAT] [GRAPHIC(S) NOT AVAILABLE IN TIFF FORMAT] [GRAPHIC(S) NOT AVAILABLE IN TIFF FORMAT]

Method 609--Nitroaromatics and Isophorone

1. Scope and Application

1.1 This method covers the determination of certain nitroaromatics and isophorone. The following parameters may be determined by this method: ------------------------------------------------------------------------

Parameter STORET No. CAS No.------------------------------------------------------------------------2,4-Dinitrotoluene............................ 34611 121-14-22,6-Dinitrotoluene............................ 34626 606-20-2Isophorone.................................... 34408 78-59-1Nitrobenzene.................................. 34447 98-95-3------------------------------------------------------------------------

1.4 The sample extraction and concentration steps in this method are essentially the same as in Methods 606, 608, 611, and 612. Thus, a single sample may be extracted to measure the parameters included in the scope of each of these methods. When cleanup is required, the concentration levels must be high enough to permit selecting aliquots, as necessary, to apply appropriate cleanup procedures. The analyst is allowed the latitude, under Section 12, to select chromatographic conditions appropriate for the simultaneous measurement of combinations of these parameters.

2. Summary of Method

2.1 A measured volume of sample, approximately 1-L, is extracted with methylene chloride using a separatory funnel. The methylene chloride extract is dried and exchanged to hexane during concentration to a volume of 10 mL or less. Isophorone and nitrobenzene are measured by flame ionization detector gas chromatography (FIDGC). The dinitrotoluenes are measured by electron capture detector gas chromatography (ECDGC). \2\

2.2 The method provides a Florisil column cleanup procedure to aid in the elimination of interferences that may be encountered.

3. Interferences

3.1 Method interferences may be caused by contaminants in solvents, reagents, glassware, and other sample processing hardware that lead to discrete artifacts and/or elevated baseliles in gas chromatograms. All of these materials must be routinely demonstrated to be free from interferences under the conditions of the analysis by running laboratory reagent blanks as described in Section 8.1.3.

3.1.1 Glassware must be scrupulously cleaned. \3\ Clean all glassware as soon as possible after use by rinsing with the last solvent used in it. Solvent rinsing should be followed by detergent washing with hot water, and rinses with tap water and distilled water. The glassware should then be drained dry, and heated in a muffle furnace at 400 [deg]C for 15 to 30 min. Some thermally stable materials, such as PCBs, may not be eliminated by this treatment. Solvent rinses with acetone and pesticide quality hexane may be substituted for the muffle furnace heating. Thorough rinsing with such solvents usually eliminates PCB interference. Volumetric ware should not be heated in a muffle furnace. After drying and cooling, glassware should be sealed and stored in a clean environment to prevent any accumulation of dust or other contaminants. Store inverted or capped with aluminum foil.

3.1.2 The use of high purity reagents and solvents helps to minimize interference problems. Purification of solvents by distillation in all-glass systems may be required.

3.2 Matrix interferences may be caused by contaminants that are co-extracted from the sample. The extent of matrix interferences will vary considerably from source to source, depending upon the nature and diversity of the industrial complex or municipality being sampled. The cleanup procedure in Section 11 can be used to overcome many of these interferences, but unique samples may require additional cleanup approaches to achieve the MDL listed in Table 1.