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Steve Knollmeyer Alpha Analytical

Analysis of PFAS Method and Sample Considerations. Steve Knollmeyer Alpha Analytical. Topics for Discussion. Overview of PFAS methodology Method modifications Target compound lists What to ask lab for. MOVING TARGET. Analytical methodologies What methods, are they applicable?

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Steve Knollmeyer Alpha Analytical

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  1. Analysis of PFAS Method and Sample Considerations Steve Knollmeyer Alpha Analytical

  2. Topics for Discussion Overview of PFAS methodology Method modifications Target compound lists What to ask lab for

  3. MOVING TARGET • Analytical methodologies • What methods, are they applicable? • Reference standard availability? • Laboratory certifications • Regulatory requirements • Requested target compound lists • Compliance guidelines, required reporting limits • What’s next?

  4. PFAS Analysis • Primary methodology • Method 537. Version 1.1 Determination of Selected Perfluorinated Alkyl Acids in Drinking Water by Solid Phase Extraction and Liquid Chromatography/Tandem Mass Spectrometry (LC/MS/MS) Sept, 2009 • Sample preparation • Solid phase extraction (SPE) • Analytical Instrumentation • Liquid chromatography / tandem mass spectrometry (LC/MS/MS)

  5. New Drinking Water Method Under Development

  6. 815-B-16-021, September 2016 • PFAS can exist as linear & branched isomers • Method 537 addresses both for PFOS (2009) • Standards not available at the time for PFOA • Discrepancies in PFOA reporting • Addressed in Tech Advisory

  7. Acids or Anions ? _ Perflurooctanesulfonic acid Perfluoroalkylcarboxylic Acids Perfluoroalkylsulfonic Acids Carboxylates Sulfonates CAS #s?? Perfluorooctanesulfonate

  8. Method 537 / 537.1 • Drinking water method, written for clean drinking water sample matrix • 14 / 18 PFAS target compound list(s) • Limitations? • Expanded target compound lists? • Silty groundwater? • Soils, biosolids…oysters?

  9. Modified Method 537? • Method 537 • “as specifically written” • Other methodologies • “Laboratory proprietary method” • LC/MS/MS • May use different or multiple SPE cartridges • May use isotope dilution approach

  10. Isotope Dilution Approach • Addition of known amount of isotopically-enriched, compound-specific internal standard • PRIOR TO SAMPLE PREPARATION • Matrix recovery correction • Analysis-specific, analyte-specific concentration normalization • Provides additional qualitative & quantitative certainty

  11. 2 New EPA SW-846 Methods in Process • (1) SW-846 Method 8327 Public Comment Draft: Jan 2019 • Non-potable water • Based on EPA Reg 5, Chicago Regional Lab, similar to ASTM D7979 • LC/MS/MS direct injection, external standard calibration • 24 analytes • (2) SW-846 Method 8328 (maybe 2020??) • Non-potable water plus soils, sediments & biosolids • LC/MS/MS SPE, isotope dilution • 24 analytes plus HFPO-DA • Consistent with DoD QSM 5.1, Table B-15

  12. "…plans to add additional analytes" "SW-846 Methods will utilize 28 day holding times"

  13. DOD QSM Version 5.1 Table B -15 (pg 1 of 15)

  14. Other Methodologies • ASTM • ISO • TOP Assay • PIGE-Total Fluorine method • Time-of-flight high resolution mass spectrometry (qTOF-MS)

  15. TOP Assay Total Oxidizable Precursors Oxidative Conversion as a Means of Detecting Precursors to Perfluoroalkyl Acids in Urban Runoff Erika F. Houtz and David L. Sedlak* Department of Civil and Environmental Engineering, University of California at Berkeley, Berkeley, California, 94720-1710 Environ. Sci. Technol. 2012, 46, 17, 9342-9349

  16. TOP (Total Oxidizable Precursor) Assay • Analysis of individual PFAS compounds using LC/MS/MS may underestimate PFAS mass • Precursors • Polyfluoroalkyl substances that can undergo transformation to form perfluoroalkyl acids • 2 aliquots • Analyze 1 normally • Treat other aliquot • KS2O8 + NaOH / 85 °6 hrs • Then analyze • Total precursors = PFAStreated – PFASuntreated

  17. Sample matrices Other than Drinking Water? • Wastewater, "silty" ground water, SPLP, etc. • Alpha runs by isotope dilution • Samples pre-spiked with extraction internal standards • Centrifuged if necessary and extracted.  • Particulate matter is included in the bottle rinse with the elution solvent • Too much particulate could interfere with bottle rinse • Centrifuging may not be possible with excessive particulate • No other option - dilutions / decant, discussion

  18. Soils & Biosolids • Alpha run by isotope dilution • Samples pre-spiked with extraction internal standards • 2 grams, 10 mLsMeOH • SPE clean up cartridge • Biosolids??

  19. Other Sample Matrices? Soils prep further modified Oysters Fish Plant tissue

  20. ?????

  21. So What Do You Analyze For? • Industry • AFFF • Landfills • Application dependent • Regulatory oversight • Source • 3 basic sources potentially have different PFAS signatures • Application • site characterization, human health / eco risk assessment, remedial design Methodology?

  22. UCMR 3 (Unregulated Contaminate Monitoring Rule) Maine screening levels for 3 6 PFAS cmpds included UCMR- Collect data for contaminants suspected to be present in drinking water, but that do not have health-based standards set under the Safe Drinking Water Act (SDWA). Every five years.

  23. EPA Method 537 - List of 14 Compounds

  24. 11/2018 UPDATE EPA Method 537.1 - Target Compound List * * * *

  25. PFOA Replacements • GenX • GenX is the trade name for the ammonium salt of hexafluoropropylene oxide–dimer acid (HFPO-DA) • HFPO-DA is the target compound listed in Method 537.1

  26. Reporting Limits (RLs) • Water samples • 2-5 ng/L (PPT) parts per trillion • 1000X lower than normal parts per billion (PPB)levels • Soil/solids/tissue • 1 ug/kg (PPB) • Biosolids-higher RL • Dewatered sludge higher based on low %solids • For example 20% solid sludge RL = 5 ug/kg (divide 1 by 0.2) • Liquid sludge with 2-5% solid even higher

  27. Wrap Up Questions? MOVING TARGET! STAY CURRENT! Steve Knollmeyer 603-498-7213 sknollmeyer@alphalab.com

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