A new method for quickly and quantitatively measuring per and poly fluorinated alkyl substances (PFASs) in drinking water has been developed. An activated carbon filter has been used to capture PFASs from drinking water through simple gravity filtration, and using particle induced gamma emission (PIGE) spectroscopy for total fluorine analysis to provide quantitative estimates for PFAS contamination in water. The activated carbon filter alone shows a strong linear correlation between total fluorine signal and PFAS concentration. Using a 2L volume this method has a limit of detection between 100-200 ppt F depending on the specific PFAS. Of the 10 PFASs tested, the filter captures long-chain PFASs more efficiently than short-chain PFASs and appears to capture sulfonate PFASs more efficiently than carboxylate PFASs. While inorganic fluoride can be an interference for total fluorine measurements as it is sometimes present naturally in ground water and often added to drinking water, we have discovered that acidifying the sample before filtration prevents fluoride from binding to the filter while leaving PFAS binding unaffected. Additionally, we have discovered that modifying the surface of the filter with a thin polymer layer can increase its PFAS extraction from water and ultimately increase the total fluorine signal more than 10-fold which lowers the detection limit from 200 ppt to well below the any health advisory limits for specific PFAS. This total fluorine method, while it cannot differentiate between specific PFASs, could be used to quickly screen for overall elevated fluorine levels in water, since the analysis takes only minutes to perform.  Furthermore, since the measurement is non-destructive, PFAS could be eluted off the filter with methanol and analyzed with subsequent liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis, the current gold standard used to identify and quantify specific PFAS compounds.

Development of a total fluorine method to screen for PFAS in drinking water

ACS Spring Meeting 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.