A review of ASTM D7979 for the analysis of per- and polyfluorinated alkyl substances in non-potable water by co-solvation with methanol and using liquid chromatography-tandem mass spectrometry.

Per- and polyfluorinated alkyl substances are large class of man-made compounds known in the media as "forever chemicals". In 2015, ASTM International published ASTM D7979, for the analysis of per- and polyfluorinated alkyl substances in non-potable water samples. This method extracts the substances by co-solvation with methanol and measures targeted compounds using liquid chromatography-tandem mass spectrometry. ASTM D7979 is a performance-based method that analyzes 31 compounds plus 14 isotopically labeled surrogates. The minimum reporting limit is approximately 10 ng/L with an analytical range of 10-200 ng/L for most compounds. Expected recovery of surrogates and spiked matrices is 70-130%. Samples containing high suspended solids can be analyzed with minimal interferences and potential loss of analyte. The method is consistent with ASTM and EPA's sustainable development goals by using reduced volumes of sample, solvent, and minimizing hazardous solvents and sample preparation materials while maintaining data quality and detection limits that are suitable for the intended use. This paper covers the rationale, outlines some of the challenges associated with analysis of per- and polyfluorinated alkyl substances, and describes the steps taken by the ASTM Committee D19 task group to develop, optimize, and validate this method.