PFAS Analytical Methods FAQs
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Determination of Per- and Polyfluoroalkyl Substances in Drinking Water by Isotope Dilution Anion Exchange Solid Phase Extraction and Liquid Chromatography/Tandem Mass Spectrometry
- 25 compounds (11 compounds are unique to EPA 533 and 14 compounds overlap with EPA 537.1)
- Holding Time: Extract within 28 days/Analyze extract within 28 days
- LCMSMS (Liquid Chromatography Tandem Mass Spectrometry) with confirmation ion
- Utilizes Isotope Dilution methodology
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Determination of Selected Per- and Polyfluorinated Alkyl Substances in Drinking Water by Solid Phase Extraction and Liquid Chromatography/Tandem Mass Spectrometry (LC/MS/MS)
- 18 compounds (4 compounds are unique to EPA 537.1 and 14 compounds overlap with EPA 533)
- Holding Time: Extract within 14 days/Analyze extract within 28 days
- LCMSMS (Liquid Chromatography Tandem Mass Spectrometry) with no confirmation ion
- Utilizes Internal Standard methodology
- Report Limits range from 2ppt (parts per thousand) – 40 ppt
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- Draft 8327 – 24 Analytes (External Standard methodology)
- Draft 1600 series – 40 analytes (Isotope Dilution methodology)
- User Defined (537 Modified etc.) up to 70 analytes (Isotope Dilution methodology) – Eurofins Analytical Laboratory
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- Source Air: EPA OTM 45 (up to 50 compounds)
- Ambient Air: Modified TO-13A / LCMSMS
- Vapor: Modified TO-17 / GCMSMS (Gas Chromatography Tandem Mass Spectrometry)
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Since it is difficult to measure for every specific PFAS compound, Total PFAS methods are also under development for the quantification of PFAS in the environment. The following two methods are being evaluated by the EPA currently.
Total Organic Fluorine (TOF): EPA is developing a potential rapid screening tool to identify total PFAS presence and absence. This eventual standard operating procedure will be used to quantify TOF.
Note: EPA is working to develop this method in 2021.
Total Organic Precursors (TOP): EPA is considering the development of a method, based on existing protocols, to identify PFAS precursors that may transform to more persistent PFAS.
Note: TOP methods are commercially available. EPA will consider the need for a thorough multi-laboratory validation study in 2021.