United States Environmental Protection Agency Environmental Monitoring Systems Laboratory Las Vegas NV 89114 Research and Development EPA/600/S4-87/009 June 1987 &EPA Project Summary Single Laboratory Validation of EPA Method 8140 L. D. Betowski and P. J. Marsden Method 8140. Organophosphorous Pesticides Parameters, of SW-846 was validated for use in the determination of 27 analytes in a single laboratory study. The method can be used for the analysis of 26 Organophosphorous pa- rameters in water, soil, and hazardous waste; the method is not suitable for monocrotophos because it showed poor recovery from soil and water. The per- formance of several GC columns, both packed and capillary, was established for the analysis of organophosphates. The use of megabore capillary GC columns over the use of packed columns specified in the current method is re- commended for multiresidue Organ- ophosphorous analysis. Two phosphorus specific detectors, the flame photo- metric (FPD) and nitrogen phosphorus (NPD). were compared in terms of linearity, specificity, and sensitivity. Sample preparation and analysis tech- niques for organophosphates in aqueous and solid matrices were tested for ruggedness in order to identify critical method parameters. A proposed modifi- cation of Method 8140 is included together with accuracy and precision data for the determination of 26 method analytes in soil and water samples. Limited recovery data is also provided for additional Organophosphorous com- pounds amenable to the method. This Project Summary was developed by EPA's Environmental Monitoring Systems Laboratory, Las Vegas, NV, to announce key findings of the research project that Is fully documented In a separate report of the same title (see Project Report ordering Information at back). Introduction Method 8140, published in SW-846, Second Edition, is reported applicable to the analysis of 20 Organophosphorous pesticides with detection limits in the range of 0.1 to 5 ng/L for water. The method is a straightforward procedure in which samples are extracted with organic solvent, are concentrated, and are analyzed by GC with a phosphorus specific detector. Water samples are extracted by the use of one of two alternate procedures. Method 3510 (separatory funnel extraction) or Method 3520 (continuous liquid-liquid extraction). Two alternate preparation techniques are specified for soil samples and nonaqueous hazardous waste samples. Method 3540 (Soxhlet extraction) and Method 3550 (extraction by sonication). The gas chromatographic separation of the or- ganophosphates is accomplished by using three packed columns, 5 percent SP- 2401 on Supelcoport, 3 percent SP-2401 on Supelcoport, or 10 percent SE-54 on Gas Chrom Q (Teflon column). Two alternate phosphorus specific GC detec- tors are recommended: the nitrogen phosphorus (NPD) or flame photometric (FPD). This report includes (1) a comparison of the recovery of 27 potential method analytes by using the sample preparation techniques specified for water and soil, (2) an evaluation of several packed and capillary columns with retention times for organophosphates of regulatory in- terest, and (3) a comparison of linearity, sensitivity, and detection limits of NPD and FPD detectors. A study of the ap- plicability of cartridge cleanup techniques for analytes of Method 8140 is also ------- presented. Results of three ruggedness tests applied to sample preparation and analysis techniques are included with critical method criteria. Method bias and precision were established by conducting recovery studies of method parameters spiked at multiple concentration into each sample matrix. Experimental Procedures Method 8140 presently specifies the use of gas chromatography (GC) with single phase packed columns for the separation and quantitative determination of organophosphorous compounds. In this study, the evaluation of four packed GC columns was conducted: (1) 5 percent SP-2401; (2) 6 percent OV-210/4 percent SP-2100; (3) 10 percent DEGS; and (4) 10 percent SP-2330. All columns were 180 cm x 2 mm ID, with 100/120-mesh Supelcoport used as packing support. Both the FPD and NPD were used as detectors for the organophosphorous pesticides. In addition to the evaluation of the above packed columns, the use of 30-m megabore capillary columns for the analysis of the organophosphorous pesticides was evaluated; the SPB-608 and the DB-210 columns were recom- mended in the modified Method 8140. The retention times and temperature programs for Method 8140 analytes on these two columns are shown in Table 1. Method 8140 was evaluated for spiked water extracted by using Method 3510 (separatory funnel shakeout) or Method 3520 (continuous extractor) and for soil and solid wastes extracted by using Methods 3540 (Soxhlet extraction) or 3550 (sonication). Ruggedness testing of Method 8140 was applied to the extraction of both water samples and soil samples. Seven variables were changed for the testing of the water samples. For the water samples, two conditions were tested for each of the following variables: duration of ex- traction, amount of sample, storage of extracts prior to analysis, amount of extraction solvent, concentration method, injection volume, and quantification method. For the soil samples, two condi- tions were tested for the following vari- ables: sonication power, percent moisture of soil, extraction solvent, length of sonication, post-extraction filtration method, final concentration step, and use of GPC cleanup. In addition, a second ruggedness testing on soil was used in which the following variables were changed: type of extraction, percent moisture, spike level, filtration of extract through sodium sulfate, concentration method, length of storage of uncon- centrated extract, and use of GPC cleanup. TaWe 1. Capillary Column Retention Times For Method 8140 Analytes Capillary Column Compound Azinphos methyl Bolster Chlorpyrifos Coumaphos Demeton, O.S Diazinon Dichlorous Dimethoate Disulfoton EPN Ethoprop Fensulfothion Fenthion Malathion Merphos Mevinphos Monocrotophos Naled Parathion, ethyl Parathion. methyl Phorate Ronnel Sulfotep TEPP Tetrachlorvinphos Tokuthion Trichloronate SPB608 38.04 35.08 26.88 38.87 15.90 20.02 7.91 20.18 19.96 36.71 16.48 35.20 29.45 28.78 21.73 12.88 20.11 17.40 27.62 23.71 17.52 22.98 18.02 5.12 32.99 24.58 28.41 DB210 37.24 37.55 25.18 39.47 17.24 19.68 12.79 27.96 20.66 36.74 18.67 36.80 28.86 32.58 32.44 18.44 31.42 19.35 33.39 32.17 18.19 23.19 19.58 10.66 33.68 39.94 29.95 Temperature Program used for Both Capillary Columns: Initial temperature Initial time Rate Final temperature Ho/dl Rate Final temperature Hold 2 50°C 1 minute 5°C/minute 140°C 10 minutes 10°C/minute 240°C 10 minutes Results and Discussion The single laboratory evaluation of Method 8140 has resulted in a modifica- tion of the method. This modified method which proposes the use of megabore capillary columns is presented as an appendix to the Project Report. The linearity range and response factor for 27 Method 8140 analytes with a NPD are presented in Table 2. Similar data with an FPD are given in Table 3. Two critical method variables for the extraction of soil were identified by rug- gedness testing. Extraction with 1:1 methylene chloride/acetone (v/v) resulted in improved recoveries over methylene chloride alone. The recoveries of or ganophosphorous pesticides were poore following GPC cleanup versus no GPC. li a second ruggedness test on the soil, thi spike level appeared to affect analyt recovery significantly. A 10-fold increasi in spiking concentration resulted in . significant improvement in sample re covery. No critical method variables wen identified in the ruggedness test for wate samples. The overall standard deviatioi calculated from the ruggedness testini for water was 5.2 percent. The recoveries were 50 to 80 percen for most spiked organophosphorous com pounds when use was made of thi Soxhlet extractor, while only 40 to 71 percent were recovered for these sami analytes by using sonication. The relativi standard deviation for the method unde either Soxhlet extraction or sonication fo most analytes is roughly equivalent (51< 15 percent). Although the extraction procedure wai not identified as a critical method variable analyte recoveries from water at low am medium concentrations were general!1 lower for continuous liquid extractioi (Method 3520) versus separatory funne (Method 3510) extraction. This may havi been due to hydrolysis of analyte in thi longer continuous extraction process. I is important to remember that this dif ference was observed in the extraction o clean water. For some environmenta samples, the loss of analytes in emulsion; formed in the separatory funnel coulc make continuous liquid extraction the preferred method. Conclusion and Recommendations The present Method 8140 is a packet column technique suitable for the analysis of twenty compounds. Because then were shortcomings in this method in th< area of GC resolution when it was applie< to a longer list of analytes, a modifiec method has been proposed. The modifie( Method 8140 of SW-846 was applied tc the determination of 27 organophos phorous analytes in water and soil. Thi! method has been validated for use witt 26 of these compounds. The methoc cannot be used for monocrotophos since recoveries of no greater than 20 percen were achieved for this compound. Thi! new version of Method 8140 allows the use of megabore capillary columns: t polar column (DB-210 or equivalent) if recommended as the primary column and a moderate polarity column (SP-60f ------- or equivalent) is proposed for the second- ary column. The modified method repre- sents an improvement over the older technique and can be used to generate data of good quality with excellent repeatability. The modified Method 8140 requires that aqueous samples be extracted with methylene chloride, and that solids be extracted with a 1:1 methylene chloride/ acetone (v/v) solvent mixture. A caution has been added that the analyst should use a drying agent only if necessary, since single laboratory results indicate that some organophosphorous analytes are lost during drying with sodium sulfate. The laboratory is allowed to use either Kuderna-Danish (K-D) or rotary evapora- tion to reduce the volume of sample extracts. Analysts are cautioned that samples should not be transferred with 100 percent hexane during sample workup as the more water soluble or- ganophosphorous compounds may be lost. No sample cleanup is required for Method 81 40 nor was one validated for its use. The information in this document has been funded wholly or in part by the United States Environmental Protection Agency under Contract No. 68-03-1958 to S-CUBED, a Division of Maxwell Laboratories, Inc., San Diego, California. It has been subject to the Agency's peer and administrative review, and it has been approved for publication as an EPA document Table 2. Response Factors For 27 Method 8140 Analytes on a Nitrogen-Phosphorus Detector . Compound Azinphos methyl Bolster Chlorpyrifos Coumephos Demeton Diazinon Dichlorvos Dimethoate Disulfoton EPN Ethoprop Fensulfothion Fenthion Malathion Merphos Mevinphos Monocrotophos Naled Parathion. ethyl Parathion, methyl Phorate Ronnel Sulfotep TEPP Tetrachlorvinphos Tokuthion Trichloronate ND = Not determined. Table 3. Response Compound Azinphos methyl Bolster Chlorpyrifos Coumaphos Demeton Diazinon Dichlorvos Dimethoate Disulfoton EPN Ethoprop Fensulfothion Fenthion Malathion Merphos Mevinphos Monocrotophos Naled Parathion, ethyl Parathion, methyl Phorate Ronnel Sulfotep TEPP Tetrachlorvinphos Tokuthion Trichloronate Range (ng) 5-500 0.545-545 5.2-520 1.05-525 13.7-274 5.8-580 4.76-4760 1.07-107 0.720-144 O.62-620 0.61-610 6.9-575 7.45-745 1.2-60O 42.6-4260 7.05-705 42.6-4260 — 1.35-675 1.28-640 1.39-139 0.525-210 6.67-266 6.52-6520 1.03-515 1.39-695 — Factors For 27 Method 8140 Analytes on a Range (ng) 5-500 0.545-218 O.52-520 0.525-525 — 1.16-232 4.76-4760 0.535-535 0.720-720 0.62-248 O.61-61O 0.690-690 0.745-745 0.60-60O 8.51-17OO 14.1-705 8.57-1700 10-5OO 0.675-675 0.640-640 1.39-278 0.525-525 0.665-266 13.0-6520 0.515-515 0.695-695 0.5-100 Response Factor IResponse/ng) 2.46x10* 6.85 xlO3 6.27x10* 2.34 x 1O4 1.10x10* 1.68x10* 2.05x10* 2.29x10* 5.42 x 10s 1.61 x 1O* 3.81 x 1O* 3.88x10* 5.15x10* 3.64x10* 4.48 xlO3 2.09x10* 2.59 xlO3 ND 3.70 x 1O* 2.74x10* 1.94x10* 3.97 xlCf 6.78x10* 3.71 xlO3 1.67x 1O3 2.21 x 10* ND Flame Photometric Detector Response Factor (Response/ng) 2.28x10* 5.12x10* 6.27x10* 2.49 x 10* ND 8.56 x 10* 3.08 xlO3 2.77x10* 2.79 x 10* 4.38x10* 3.29 x 1O* 1.86 xlO* 2.95x10* 2.95 x 1O* 2.48x10* 2.38 x 1O* 2.47 xlO3 1.46 xlO3 3.53 xlO* 2.76x10* 3.04 x 10* 3.35x10* 6.97x10* 2.90 xlO2 3.11 x 10* 1.96x10* 2.98x10* ND = Not determined. ------- PaulJ. Marsden is with Maxwell Laboratories. Inc., La Jolla, CA 92038-1620; the EPA author Leon D. Betowski is with the Environmental Monitoring Systems Laboratory, Las Vegas, NV89114. Llewellyn Williams is the EPA Project Officer (see below). The complete report, entitled "Single Laboratory Validation of EPA Method 8140." (Order No. PB87-177 507/A S; Cost: $ 18.95, subject to change} will be available only from: National Technical Information Service 5285 Port Royal Road Springfield, VA22161 Telephone: 703-487-4650 The EPA Project Officer can be contacted at: Environmental Monitoring Systems Laboratory U.S. Environmental Protection Agency P.O. Box 15027 Las Vegas. NV 89114 United States Environmental Protection Agency Center for Environmental Research Information Cincinnati OH 45268 U.S.CFfiC'iAi . y* •-v —n-v rn sMsiAii .ILN; ."3/ ; ^-F ; /.''''".':'! .- U •].' 'il Official Business Penalty for Private Use $300 EPA/600/S4-87/009, ------- |