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Analysis of 203 Pesticide Residues in Drinking water using SPE, GC/MS/MS and LC/MS/MS

Analysis of 203 Pesticide Residues in Drinking water using SPE, GC/MS/MS and LC/MS/MS. Robert Sheridan New York State Dept. of Ag & Markets USDA PDP Program. The Pesticide Data Program (PDP).

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Analysis of 203 Pesticide Residues in Drinking water using SPE, GC/MS/MS and LC/MS/MS

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  1. Analysis of 203 Pesticide Residues in Drinking water using SPE, GC/MS/MS and LC/MS/MS Robert Sheridan New York State Dept. of Ag & Markets USDA PDP Program

  2. The Pesticide Data Program (PDP) • Began by USDA in 1991 as a data collection device to determine the amount of pesticide residues in the typical American diet • In 1996 the Food Quality Protection act required all pesticide residue tolerances to be reexamined based on exposure data • Data collection not enforcement

  3. The Need For Drinking WaterAnalysis • Since 1991 various foods were examined for low as well as high levels of pesticides • fruits,vegetables,milk • In 2000 the New York and California PDP labs were asked to develop analytical methods for drinking water • The method was to screen for as many pesticides as possible including some high priority compounds

  4. Water sampling • 11 finished drinking water sites throughout New York State • Each site sampled twice per month

  5. Goals of water analysis method • The method must include as many pesticides as possible at low detection limits ( ~10ng/L-ppt) • Several extraction methods • Several analysis methods • GC/MS/MS – LC/MS/MS • The method must not be so labor intensive as to be impractical • Should be automated SPE • Each analysis screen should include many compounds per injection to minimize the number of injections

  6. Range of compounds • GC amenable • Organophosphated, organochlorinated, non-heteroatom semivolatile • LC amenable • Gradient 1 - 0.15%acetic acid/MeOH 85:15 • N-methyl carbamates • Acid herbicides • Sulfonyl ureas • Imidizolinones • Gradient 2 – 0.15%acetic acid/MeOH 50:50 • Chloroacetanilide herbicide metabolites

  7. 3 Methods per sample • SPE with MCX phase (Waters) 1 litre GC/MS/MS (ion trap w/ 0.31um ID cap. column) GC-FPD (megabore 0.53 um ID column) • SPE with carbon phase ENVI- carb (Supelco) 1 litre LC/MS/MS (triple quadrupole) • SPE with C-18 phase 100ml LC/MS/MS (triple quadrupole) • chloroacetanilide herbicide metabolites

  8. Extraction Method 1 • precondition MCX SPE column with 3ml HIP (3:1 hexane : isopropanol) • Add 10ml of methanol to a 1 litre water sample. Add 1 g sodium thiosulfate • Condition SPE tube with 3ml MEOH and 3ml DDI water • Using autotrace (Zymark) load sample (~25ml/min) and dry • Place 0.5ml toluene in concentrator tube. Elute into tube with 10ml HIP and 5ml MEOH. • Solvent exchange to 0.5ml acetone. Add 0.5ml toluene andconcentrate to 0.5ml

  9. Analysis 1 Extract 1 • Analyzed by Saturn (Varian) GC/MS/MS ion trap • 91 compounds screened with instant confirmation and quantitation using fragment ion ratio match and spectrum match • MS/MS allows excellent sensitivity and selectivity with two injection on one instrument • Analyzed by GC-FPD • 62 relatively polar organophosphated pesticides that are difficult to resolve on narrow bore capillary columns • Confirmed by GC/MS/MS PolarisQ (ThermoQuest)

  10. Method 1 recoveries (from 153) % recovery % recovery • Dimethoate 98 chlorpyriphos 71 • Terbufos 75 trifluralin 68 • Diazinon 62 simazine 94 • Phorate 73 lindane 78 • Fenitrothion 78 quintozene 67 • Parathion 89 chlordane-c 79 • Ethion 76 chlordane-t 76 • Pirimiphos-m 66 endosulfanII 92 Methadithion 91 alachlor 93

  11. water sample# 745 GC results Desethyl-atrazine 49.8 ppt Desisopropyl atrazine 21.8 ppt Atrazine 63.2 ppt Metolachlor 13.8 ppt Simazine 9.5 ppt

  12. Desethyl atrazine 49.8ppt

  13. Desisopropyl atrazine 21.8ppt

  14. Atrazine 63.2 ppt

  15. Metolachlor 13.8 ppt

  16. Simazine 9.5 ppt

  17. Sample site 2 triazines and metabolites ppt atrazine atrazine 2001 2002

  18. Extraction Method 2 • Add 1ml of Hydroxylamine Hydrochloride to a 1 litre sample. Add 10 gm NaCl and 1.5ml Glacial acetic acid and mix. • Condition ENVI-carb (Supelco) SPE tube with 2 x 5 ml 80:20 methylene chloride:methanol followed by 2 x 5ml DDI water. • Load sample using Autotrace (Zymark) at ~ 25ml/min and dry. • Elute with 2ml MeOH followed by 2 x 5ml 80:20 MeCl:MeOH and 5 ml acetone. • Concentrate and solvent exchange 0.5ml of LC mobile phase.

  19. Analysis 2 Extract 2 • Analyzed by Micromass Ultima LC/MS/MS triple quadrupole • 44 compounds screened with instant confirmation and quantitation using fragment ion ratio match • MS/MS allows excellent sensitivity and selectivity with two injections on one instrument • Since some compounds ionize positive ESI and some ionize negative ESI , two injections per sample is necessary. Compounds separated based on best ionization polarity efficiency.

  20. Method 2 Recoveries (from 44) aldicarb 8 siduron 83 Neburon 61 clopyralid 71 benomyl 82 picloram 70 oxamyl 55 bentazon 77 methomyl 87 2,4-D 76 imazapyr 85 dichlorprop 94 carbofuran-3OH 84 triclopyr 81 bromacil 67 2,4,5-T 94 nicosulfuran 84

  21. Sample # 659 bentazon 19.1ppt Ion 239.1 to 197.3 Ion 239.1 to 175.4 Ion 239.1 to 132.3

  22. Extraction Method 3(chloroacetanilide herbicide metabolites) • Condition C-18 SPE tube with 2 ml MeOH and 2ml DDI water. • Load 100ml sample at ~ 10 ml/min with N2 pressure and dry. • Elute with 5ml MeOH . • Concentrate and solvent exchange 0.2ml of LC mobile phase.

  23. Analysis 3 Extract 3 Analyzed by Micromass Ultima LC/MS/MS triple quadrupole • 6 chloroacetanilide herbicide metabolites • Alachlor oxanilic acid • Alachlor ethanesulfonic acid • Acetochlor oxanilic acid • Acetochlor ethanesulfonic acid • Metolachlor oxanilic acid • Metolachlor ethanesulfonic acid • The oxanilic acids (oa) and the sulfonic acids (esa) don’t effectively resolve, but MS/MS produces fragments in unique , reproducible ratios, thereby providing an excellent confirmation.

  24. Recoveries from method 3 Analyte% Acetochlor ESA 51 Acetochlor OA 48 Alachlor ESA 51 Alachlor OA 55 Metolachlor ESA 55 Metolachlor OA 54

  25. VB339 27-Feb-2002 18:28:27 02P00199 JANCWR Sm (Mn, 2x7) 2: MRM of 12 Channels ES- 33.47 327.8 > 121.2 100 99697 6.04e4 Area % 0 02P00199 JANCWR Sm (Mn, 2x7) 2: MRM of 12 Channels ES- 327.8 > 135.2 100 1.43e4 Area % 0 Time 0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00 40.00 45.00 50.00 Sample# 199 metolachlor oa 81 ppt Ion 277.8 to 174.1 327.8 to 121.2 33.51 23942 Ion 277.8 to 206.0 327.8 to 135.2

  26. Sample# 200 metolachlor esa 68 ppt Ion 327.8 to 121.2 Ion 327.8 to 135.2

  27. water sample# 204 (sample site 10) • GC results • Desethyl-atrazine 74.0 ppt • Atrazine 46.6 ppt • Metolachlor3.9 ppt • LC results • Metolachlor oa261 ppt • Metolachlor esa519 ppt

  28. Water samples from December 2001 • Metolachlor oa esa ppt ppt ppt Sample site # 04 13.6 122 101 05 10.9 82.9 77.9 07 35.5 112 196 10 3.8 465 1205 11 19.3 46.2 167

  29. Sample site 1 and 2 ppt (ng/L) 2 site site

  30. Sample site 6 and7 Metolachlor (ppt) 2001 2002

  31. Sample site 6 and 7 ppt 6 7

  32. Improvements to be made More compounds added to screen • Several more chloroacetanilide herbicide metabolites • Propachlor oxanilic acid, ethanesulfonic acid • Dimethenamid oxanilic acid, ethanesulfonic acid • More carbamates • More sulfonylurea herbicides

  33. Acknowledgments • Thanks to • USDA PDP program • N.Y. State Dept. of Ag. & Markets personnel • USGS Denver Colorado and Lawrence Kansas labs PDP website – www.ams.usda.gov/science/pdp

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