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Richard Grace , Coreen Hamilton, Million Woudneh

“ANALYSIS OF CURRENT USE PESTICIDES IN ENVIRONMENTAL AND WASTEWATER SAMPLES BY HIGH RESOLUTION GC WITH HIGH RESOLUTION MASS SPECTROMETRIC DETECTION”. Richard Grace , Coreen Hamilton, Million Woudneh AXYS Analytical Services Ltd. , Sidney, BC, Canada. AXYS ANALYTICAL SERVICES LTD.

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Richard Grace , Coreen Hamilton, Million Woudneh

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  1. “ANALYSIS OF CURRENT USE PESTICIDES IN ENVIRONMENTAL AND WASTEWATER SAMPLES BY HIGH RESOLUTION GC WITH HIGH RESOLUTION MASS SPECTROMETRIC DETECTION” Richard Grace, Coreen Hamilton, Million Woudneh AXYS Analytical Services Ltd. , Sidney, BC, Canada AXYS ANALYTICAL SERVICES LTD. NELAP ACCREDITED / ISO 17025 CERTIFIED

  2. AGENDA • Purpose (s) of Analysis • Development History • Details of the Method • Detection Limits and Method QC • Applications and Results

  3. PURPOSE (s) of ANALYSIS • Analysis of Wide Variety of Pesticides • Legacy (OC) Pesticides • Current Use Pesticides (Canada / U.S. Focus) • “Multi-Residue Pesticide Test” or “MRES” • Improvements in Sensitivity and Selectivity • Improvement in Detection Limits vs. Reference Methods (10 – 1000X lower detection limits vs. non 1600 series EPA methods) – meet ambient criteria where established • Reduction of False Positives and Matrix Effects by Use of HRMS and Serial Isotope Dilution / RRF Quantification

  4. PURPOSE (s) of ANALYSIS • Applicable to Wide Variety of Matrices • Platform for Analysis in Most Matrices (1600 series) • Water – Surface, Ground, Effluent, Potable, High Volume Sampling on XAD Resin • Solids – Soil, Sediment, POTW Biosolids • Tissue / Serum (current development work) • Reduction of Pre-Laboratory Work • Reduction in number / size of samples • Reduction in compositing / homogenization for broad reconnaissance of Pesticides

  5. HISTORY of DEVELOPMENT • 2003 - Initial Method Development for Environment Canada (Pacific Region) for Aqueous Samples • 2003 – 2005 – Groundwater / Surface Water Survey for Environment Canada in Lower Fraser Valley • 2005 – Application to Soils / Sediments • 2006 – Application / Validation to POTW Influent / Effluent / Biosolids for U.S. EPA Office of Water • 2006 – High Volume Water Application / Collection on XAD Resin Developed • 2007 – Further Method Refinement and Validation Under Contract to U.S. EPA Office of Water • 2007 – Application of Method to Tissue and Serum

  6. ANALYTES • CURRENT LIST • 35 OC Pesticides and Metabolites • 20 Organophosphorous Compounds • 7 Triazine Compounds • 2 Pyrethroid Groups • 14 Organonitrogen Compounds

  7. RATIONALE for ANALYTE SELECTION • Current or Historic Use • Availability of Standards and Appropriate Surrogates • Capture by SPE cartridge • Analyte Stability (Matrix and Instrument) • Appropriate monitoring ions • Validation of Positive Identification

  8. OVERVIEW of ANALYSIS

  9. EXTRACTON DETAILS (Aqueous) • Weigh 1L bottle, and all steps in transfers • Transfer water to 2L sep. funnel, rinse sample container with DCM, transfer DCM to 2L sep. funnel • Add surrogates in acetone (1mL), include rinses • Extract through shaking ( 3 x 100 mL DCM) • Combine extracts, then dry with anhydrous NaSO4 • Transfer to round bottom with 1 ml keeper toluene and roto vap to 1 mL tube, concentrate to 100ul by N2 • Makeup to 1mL in 1:2:1 ethyl acetate, acetonitrile, toluene

  10. EXTRACTION DETAILS (Solid) • 1 -5 g dry weight in beaker, add anhydrous powdered sodium sulfate, equilibrate 30 min. • Load to soxhlet thimble, add surrogates • Add 300 mL DCM to soxhlet, add thimble • Soxhlet 16 hours • RotoVap to 1 ml, dry with sodium sulfate if necessary, filter through glass wool column • Continue as per aqueous procedure

  11. SPE CLEANUP DETAILS • SPE Cartridge Type – 1 g aminopropyl bonded silica column • Solvent – 1:2:1 ethyl acetone, acetonitrile, toluene • Condition using 2 X 3 mL (column volume) • Load sample followed by 1 mL rinse • Elute with 11 mLs • Concentrate to 1 mL by RotoVap • Transfer to centrifuge tubes with hexane rinse • Concentrate to 100 uL using gentle nitrogen

  12. MICROSILICA COLUMN CLEANUP DETAILS • Makeup extract to 1mL in Hexane • Wet microsilica column (Silica AR 100-200 mesh from Mallinckrodt) with 5-10 mLs Hexane • Load sample followed by 500uL hexane rinse, 2 x 300uL rinse 10% MeOH/ 90% DCM • Elute with 5 mL 10% MeOH/90% DCM, combine with rinses • Add 5 mL acetone and 1 mL iso-octane, rotovap to 1 mL • Transfer to centrifuge tube with hexane rinses, concentrate to 20 - 300 uL, transfer to microvial, add recovery standards

  13. ANALYSIS DETAILS • All Analysis performed with Micromass Ultima HRMS with Agilent 6890 GC, CTC autosampler, alpha data system running Opus 6.3 software • DB-17 capillary GC column (30m, 0.25 mm i.d., 0.25 um film thickness, direct couple to MS source • 8,000 static mass resolution in EI mode • Multiple Ion detection – two ions for each target* and surrogate • 20 – 400 uL typical extract volume, 1-2 uL injection volume

  14. INSTRUMENT DETAILS (cont.) • 2 runs • Run 1 – OC compounds, OP compounds, Triazine compounds, Pyrethroids • Run 2 – Organonitrogen compounds • Injector temperature and ramping is key difference • 220C for Run 1 injector temp. • 260C for Run 2 injector temp. • Bracketed calibration during run • Calibration vs. 6 point linearity

  15. AQUEOUS DETECTION LIMITS • Determined by Federal Register (USA) 40 CFR Part 136, Appendix B, October 26,1984 • OC Pesticides – 0.4 pg/L to 60.7 pg/L, • OP Pesticides - 2.6 to 98.9 pg/L, • Triazines – 1.5 to 12.7 pg/L, • Pyrethroids – 22 to 45 pg/L, • Organonitrogen – 0.53 to 9.41 ng/L, • Sample Detection Limits (similar to EPA 1613b) often used to reduce DLs 2-5X from calculated MDLs in clean matrices

  16. DETECTION LIMIT NOTES • Clean Matrix MDLs follow Aqueous patterns, units in pg/g • POTW Effluent generally raises DLs by 10X • POTW Influent generally raises DLs by 40X • POTW Biosolids generally raises DLs by to 0.2 to 70 ng/g

  17. STANDARD METHOD QC – Standards and Surrogates • Non-labeled standards supplied by Accustandard (78 compounds) • Carbon labeled standards supplied by Cambridge Isotope Laboratories • 21 C13 labeled OC Pesticides • 1 permethrin (cis/trans) mix • 2 ON Compounds (Alachlor, Metalochlor) • 1 OP Compound (Fonofos) • 1 Triazine Compound (Atrazine) • Deuterated surrogates (linuran, azinophos methyl, diazinon) supplied by Dr. Ehrenstorfer Gmbh • Recovery Standards (C13 PCB 52,138) supplied by Wellington Laboratories Inc.

  18. METHOD QC CRITERIA • Max. Batch Size (including QC) is 20 samples (8 to 14 is more common) • Each Batch contains: • method blank • duplicate • Laboratory Control Sample (LCS) • MS/MSD, SRM,CRM included by request and applicability • LCS Recovery 50-150 most common, some wider specs. if reproducibility high

  19. QA ACCEPTANCE CRITERA • EPA Tier 1 Validation Protocols for Single Laboratory Method for IPR, MS/MSD, and MDL criteria • Duplicate Criteria – 40% RPD for Analytes 10X above MDL • Bracketing Cal. – 40% RSD for targets detected • Cal. Ver – 25% RSD for native analytes with exact labeled standards, 35% for others • Linearity (ICAL) – 25% RSD for native analytes that have exact labeled standards, 35% for others

  20. APPLICATIONS and RESULTS • To date N > 500 samples • 50 % Groundwater / Surface Water (diverse locations) • 35% POTW influent/effluent/biosolids • 15% sediments / high volume water / other • Continuous Improvement has led to 5 method revisions. Key experiences in; • Spiking levels and standards maintenance / grouping • Bench “technique” in extraction / cleanup • Sample size and final extract options to limit matrix effects and maintain instrument cleanliness • Use of Method QC to update acceptance criteria

  21. APPLICATIONS and RESULTS (cont.) • “Detects” vary widely dependant on matrices • Many compounds are readily degraded by biological activity, photolysis, or low persistency. Generally, metabolites are not the target of the analysis. • Compounds detected vary widely dependant on region • Urban vs. rural • Type of Agricultural Activity • Regulatory Action

  22. NEXT STEPS • Peer Review of draft method by EPA – Q3/4 2007 • Further processing of samples to develop further statistical information • Tissue / Serum Application • Multi-Lab Validation? • Questions?

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