617有机磷农药和PCBs

Method 617 The Determination of Organohalide Pesticides and PCBs in Municipal and Industrial Wastewater Method 617 The Determination of Organohalide Pesticides and PCBs in Municipal and Industrial Wastewater 1. SCOPE AND APPLICATION 1.1 This method covers the determination of certain organohalide pesticides and PCBs. The following parameters can be determined by this method: Parameter Storet No. CAS No. Aldrin 39330 309-00-2 "-BHC 39337 319-84-6 ß-BHC 39338 319-85-7 *-BHC 39259 319-86-8 (-BHC 39340 58-89-9 Captan 39640 133-06-2 Carbophenothion -- 786-19-6 Chlordane 39350 57-74-9 4,4′-DDD 39310 72-54-8 4,4′-DDE 39320 72-55-9 4,4′-DDT 39300 50-29-3 Dichloran -- 99-30-9 Dicofol 39780 115-32-2 Dieldrin 39380 60-57-1 Endosulfan I 34356 959-98-8 Endosulfan II 34361 33213-65-9 Endosulfan sulfate 34351 1031-07-8 Endrin 39390 72-20-8 Endrin aldehyde 34366 7421-93-4 Heptachlor 39410 76-44-8 Heptachlor epoxide 39420 1024-57-3 Isodrin 39430 465-73-6 Methoxychlor 39480 72-43-5 Mirex 39755 2385-85-5 PCNB 39029 82-68-8 Perthane 39034 72-56-0 Strobane -- 8001-50-1 Toxaphene 39400 8001-35-2 Trifluralin 39030 1582-09-8 PCB-1016 34671 12674-11-2 PCB-1221 39488 11104-28-2 PCB-1232 39492 11141-16-5 PCB-1242 39496 53469-21-9 PCB-1248 39500 12672-29-6 PCB-1254 39504 11097-69-1 PCB-1260 39508 11096-82-5 Method 617 1.2 This is a gas chromatographic (GC) method applicable to the determination of the compounds listed above in industrial and municipal discharges as provided under 40 CFR 136.1. Any modification of this method beyond those expressly permitted shall be considered a major modification subject to application and approval of alternative test procedures under 40 CFR 136.4 and 136.5. 1.3 The method detection limit (MDL, defined in Section 15) for many of the parameters are 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 The sample extraction and concentration steps in this method are essentially the same as in Method 614. Thus, a single sample may be extracted to measure the parameters included in the scope of both of these methods. When cleanup is required, the concentration levels must be high enough to permit selecting aliquots, as necessary, in order to apply appropriate cleanup procedures. Under gas chromatography, the analyst is allowed the latitude to select chromatographic conditions appropriate for the simultaneous measurement of combinations of these parameters (see Section 12). 1.5 This method is restricted to use by or under the supervision of analysts experienced in the use of gas chromatography 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. 1.6 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. Section 14 provides gas chromatograph/mass spectrometer (GC/MS) criteria appropriate for the qualitative confirmation of compound identifications. 2. SUMMARY OF METHOD 2.1 A measured volume of sample, approximately 1 L, is extracted with 15% methylene chloride in hexane using a separatory funnel. The extract is dried and concentrated to a volume of 10 mL or less. Gas chromatographic conditions are described which permit the separation and measurement of the compounds in the extract by electron capture gas chromatography. 2.2 Method 617 represents an editorial revision of two previously promulgated U.S. EPA methods for pesticides and for PCBs. While complete method validation data is not1 presented herein, the method has been in widespread use since its promulgation, and represents the state of the art for the analysis of such materials. 2.3 This method provides selected cleanup procedures to aid in the elimination of interferences which may be encountered. Method 617 3. INTERFERENCES 3.1 Method interferences may be caused by contaminants in solvents, reagents, glassware, and other sample processing apparatus that lead to discrete artifacts or elevated baselines in gas chromatograms. All reagents and apparatus must be routinely demonstrated to be free from interferences under the conditions of the analysis by running laboratory reagent blanks as described in Section 8.5. 3.1.1 Glassware must be scrupulously cleaned. Clean all glassware as soon as possible2 after use by thoroughly rinsing with the last solvent used in it. Follow by washing with hot water and detergent and thorough rinsing with tap and reagent water. Drain dry, and heat in an oven or muffle furnace at 400°C for 15 to 30 minutes. Do not heat volumetric ware. Thermally stable materials, such as PCBs, may not be eliminated by this treatment. Thorough rinsing with acetone and pesticide-quality hexane may be substituted for the heating. After drying and cooling, seal and store glassware 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 the EC detector is used. These compounds generally appear in the chromatogram as large late-eluting peaks, especially in the 15% and 50% fractions from the Florisil column cleanup. 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 occurs when plastics are handled during extraction steps, especially when solvent-wetted surfaces are handled. Interferences from phthalates can 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. The interferences from phthalate esters can be3,4 avoided by using a microcoulometric or electrolytic conductivity detector. 3.3 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 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. 4. SAFETY 4.1 The toxicity or carcinogenicity of each reagent used in this method has not been precisely defined; however, each chemical compound must 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 Method 617 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 for the5-7 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: aldrin, benzene hexachlorides, chlordane, heptachlor, PCNB, PCBs, and toxaphene. Primary standards of these toxic materials should be prepared in a hood. 5. APPARATUS AND MATERIALS 5.1 Sampling equipment, for discrete or composite sampling. 5.1.1 Grab-sample bottle: Amber borosilicate or flint glass, 1-L or 1-quart volume, fitted with screw-caps lined with TFE-fluorocarbon. Aluminum foil may be substituted for TFE if the sample is not corrosive. If amber bottles are not available, protect samples from light. The container 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): Must incorporate glass sample containers for the collection of a minimum of 250 mL. Sample containers must be kept refrigerated at 4°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 must be thoroughly rinsed with methanol, followed by repeated rinsings with reagent 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: 125-mL, 1000-mL, and 2000-mL, with TFE-fluorocarbon stopcock, ground-glass or TFE stopper. 5.2.2 Drying column: Chromatographic column 400 mm long by 19 mm ID with coarse-fritted disc. 5.2.3 Chromatographic column: 400 mm long by 19 mm ID with coarse-fritted disc at bottom and TFE-fluorocarbon stopcock (Kontes K-420540-0224 or equivalent). 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. Method 617 5.2.6 Snyder column, Kuderna-Danish: three-ball macro (Kontes K-503000-0121 or equivalent). 5.2.7 Vials: Amber glass, 10- to 15-mL capacity with TFE-fluorocarbon-lined screw-cap. 5.3 Boiling chips: Approximately 10/40 mesh. Heat at 400°C for 30 minutes or perform a Soxhlet extraction with methylene chloride. 5.4 Water bath: Heated, with concentric ring cover, capable of temperature control (±2°C). The bath should be used in a hood. 5.5 Balance: Analytical, capable of accurately weighing to the nearest 0.0001 g. 5.6 Shaker: Laboratory, reciprocal action. 5.7 Gas chromatograph: 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. 5.7.1 Column 1: 180 cm long by 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 15. Alternative columns may be used in accordance with the provisions described in Section 12.1. 5.6.2 Column 2: 180 cm long by 4 mm ID glass, packed with 3% OV-1 on Supelcoport (100/120 mesh) or equivalent. 5.6.3 Detector: Electron capture. This detector has proven effective in the analysis of wastewaters for the parameters listed in the scope and was used to develop the method performance statements in Section 15. Alternative detectors, including a mass spectrometer, may be used in accordance with the provisions described in Section 12.1. 6. REAGENTS 6.1 Reagent water: Reagent water is defined as a water in which an interferant is not observed at the method detection limit of each parameter of interest. 6.2 Acetone, hexane, isooctane, methylene chloride: Pesticide-quality or equivalent. 6.3 Ethyl ether: Nanograde, redistilled in glass if necessary. Must be free of peroxides as indicated by EM Quant test strips (available from Scientific Products Co., Cat. No. P1126- 8, and other suppliers). Procedures recommended for removal of peroxides are provided with the test strips. After cleanup, 20 mL ethyl alcohol preservative must be added to each liter of ether. 6.4 Acetonitrile, hexane-saturated: Mix pesticide-quality acetonitrile with an excess of hexane until equilibrium is established. Method 617 6.5 Sodium sulfate: ACS, granular, anhydrous. Heat in a shallow tray at 400°C for a minimum of four hours to remove phthalates and other interfering organic substances. Alternatively, heat 16 hours at 450 to 500°C in a shallow tray or Soxhlet extract with methylene chloride for 48 hours. 6.6 Sodium chloride solution, saturated: Prepare saturated solution of NaCl in reagent water and extract with hexane to remove impurities. 6.7 Sodium hydroxide solution (10N): Dissolve 40 g ACS grade NaOH in reagent water and dilute to 100 mL. 6.8 Sulfuric acid solution (1+1): Slowly add 50 mL H SO (sp. gr. 1.84) to 50 mL of reagent2 4 water. 6.9 Mercury: Triple-distill. 6.10 Florisil: PR grade (60/100 mesh). Purchase activated at 675°C and store in dark in glass container with ground-glass stopper or foil-lined screw-cap. Before use, activate each batch at least 16 hours at 130°C in a foil-covered glass container. 6.11 Stock standard solutions (1.00 µg/µL): 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 approximately 0.0100 g of pure material. Dissolve the material in pesticide-quality isooctane and dilute to volume in a 10-mL volumetric flask. Larger volumes may be used at the convenience of the analyst. If compound purity is certified at 96% or greater, the weight may be used without correction to calculate the concentration of the stock standard. Commercially-prepared stock standards may 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 TFE-fluorocarbon-sealed screw-cap vials. Store at 4°C and protect from light. Frequently check stock standard solutions 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 6 months, or sooner if comparison with check standards indicates a problem. 7. CALIBRATION 7.1 Establish gas chromatographic operating parameters equivalent to those indicated in Table 1. The gas chromatographic system may be calibrated using either the external standard technique (Section 7.2) or the internal standard technique (Section 7.3). 7.2 External standard calibration procedure. Method 617 7.2.1 For each parameter of interest, prepare calibration standards at a minimum of three concentration levels by adding accurately measured volumes of one or more stock standards to a volumetric flask and diluting to volume with isooctane. One of the external standards should be representative of a concentration near, but above, the method detection limit. The other concentrations should correspond to the range of concentrations expected in the sample concentrates or should define the working range of the detector. 7.2.2 Using injections of 1 to 5 µL of each calibration standard, tabulate peak height or area responses against the mass injected. The results can be used to prepare a calibration curve for each parameter. Alternatively, the ratio of the response to the mass injected, defined as the calibration factor (CF), may be calculated for each parameter at each standard concentration. If the relative standard deviation of the calibration factor is less than 10% over the working range, the average calibration factor can be used in place of a calibration curve. 7.2.3 The working calibration curve or calibration factor must be verified on each working shift by the measurement of one or more calibration standards. If the response for any parameter varies from the predicted response by more than ±10%, the test must be repeated using a fresh calibration standard. Alternatively, a new calibration curve or calibration factor must be prepared for that parameter. 7.3 Internal standard calibration procedure: To use this approach, the analyst must select one or more internal standards 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. Due to these limitations, no internal standard applicable to all samples can be suggested. 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 representative of a concentration near, but above, the method detection limit. The other concentrations should correspond to the range of concentrations expected in the sample concentrates, or should define the working range of the detector. 7.3.2 Using injections of 1-5 µL of each calibration standard, tabulate the peak height or area responses against the concentration for each compound and internal standard. Calculate response factors (RF) for each compound as follows: Method 617 Equation 1 where A = Response for the parameter to be measureds A = Response for the internal standardsi C = Concentration of the internal standard, in ug/Lis C =Concentration of the parameter to be measured, in ug/Ls If the RF value over the working range is constant, less than 10% relative standard deviation, the RF can be assumed to be invariant and the average RF may be used for calculations. Alternatively, the results may be used to plot a calibration curve of response ratios, A /A against RF.s is 7.3.3 The working calibration curve or RF must be verified on each working shift by the measurement of one or more calibration standards. If the response for any parameter varies from the predicted response by more than ±10%, the test must be repeated using a fresh calibration standard. Alternatively, a new calibration curve must be prepared for that compound. 7.4 The cleanup procedure in Section 11 utilizes Florisil chromatography. Florisil from different batches or sources may vary in adsorptive capacity. To standardize the amount of Florisil which is used, the use of the lauric acid value is suggested. This procedure8 determines the adsorption from hexane solution of lauric acid, in milligrams, per gram of Florisil. The amount of Florisil to be used for each column is calculated by dividing this factor into 110 and multiplying by 20 g. 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 interference from the reagents. 7.6 The multipeak materials included in this method present a special calibration problem. Recommended procedures for calibration, separation and measurement of PCBs is discussed in detail in the previous edition of this method. Illustrated methods for the1 calibration and measurement of chlordane and strobane/toxaphene are available elsewhere.9 8. QUALITY CONTROL 8.1 Each laboratory using 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 the analysis of spiked samples as a continuing check on Method 617 performance. The laboratory is required to maintain performance records to define the quality of data that is generated. 8.1.1 Before performing any analyses, the analyst must demonstrate 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