PFAS Method Harmonization: Finding Common Analytical Ground

Method harmonization takes center stage as moderator Bryan Vining opens a discussion on one of per- and polyfluoroalkyl substances (PFAS) analysis's thorniest problems: too many compounds, and too many competing standards. With methods from the EPA, ISO, EN, and ASTM all targeting different compound lists and matrices, Vining asks the panel what it would take to reach consensus, and whether a single governing body should lead that effort.

David Megson, reader in chemistry and environmental forensics at Manchester Metropolitan University, argues that chasing standardized, highly accurate measurements for one or two compounds at a time is the wrong starting point given how many PFAS remain unmeasured. He proposes a tiered approach: run a total PFAS measurement first to flag whether a sample warrants concern, then apply targeted methods and calculate what percentage of that total has actually been captured. Where recovery is low, he says, that signals a broader "cloud" of PFAS that targeted lists are missing entirely.

Pasquale Avino, associate professor in analytical and environmental chemistry at the University of Molise, agrees that the sheer volume of compounds makes a single, all-encompassing guideline unrealistic in the near term. He suggests concentrating harmonization efforts on the main compound classes found most frequently across matrices, then expanding methodology incrementally, drawing a parallel to the years-long process of standardizing acrylamide analysis decades earlier.

Vining adds another layer of difficulty: the scarcity of toxicological data for most PFAS compounds, which makes it hard to know how much risk a given detection actually represents. He notes that even within a single country, achieving comparable results between labs is a challenge, and that international harmonization introduces political as well as scientific complexity, since different countries prioritize different compounds. The conversation sets up a natural transition to methods aimed at capturing PFAS that can't be individually targeted, including total oxidizable precursor assay and total organic fluorine testing.