A novel method for detecting per- and polyfluoroalkyl substances (PFAS) by colorimetric emulsion extraction

Per- and polyfluoroalkyl substances (PFAS) are a class of fluorinated contaminants of concern due to their long environmental persistence, biological uptake and toxicological implications. Mass spectrometry is currently heavily utilized for PFAS analysis and is capable of precise and selective measurements down to parts per trillion (ppt). However, these are labor-intensive laboratory-only methods that require a substantial expertise and specialized equipment, resulting in high cost and long waiting periods which limit their utility in providing rapid, high-quantity and data rich (large number of samples) PFAS contamination screening capability at both local and regional scales. A rapid and fieldable screening method is needed to improve surveying efficiency to enable prioritization of resources where in-depth standard analysis is required. In this manuscript, a novel emulsion extraction methodology is introduced which isolates PFAS from aqueous media. When paired with colorimetric techniques, the method facilitates rapid detection of PFAS at concentrations ranging from part-per-million (ppm) to part-per-trillion (ppt) within minutes; herein, we demonstrate visual (naked eye) colorimetric detection of PFOA below 30 ppt. This semi-quantitative emulsion extraction method represents a new means for concentrating PFAS for both detection and remediation purposes in a cost-effective and scalable manner. The cost to construct the prototype kit used in this study-which is indefinitely reuseable-using commercially sourced components and 3D printed housing was less than $150, with material costs per test of less than $2. When fully developed, the kit may therefore be deployed to facilitate efficient screening for PFAS to expedite assessments in the field or in facilities, allowing for rapid identification of sites requiring more detailed laboratory analysis.