Progress in the Detection and Quantification of Per- and Polyfluoroalkyl Substances (PFASs) in Surface Water

Abstract

Per- and polyfluoroalkyl substances (PFASs) as a category encompass over 9000 synthetic chemical species with demonstrated links to negative health outcomes, largely attributed to ingestion and bioaccumulation via drinking water. PFASs vary widely in their physicochemical properties but categorically contain at least one carbon chain characterized by multiple C–F bonds. The relative strength of the C–F bond (130 kcal mol−1) results in environmental persistence based on sluggish degradation kinetics (e.g. by photolysis). Owing to various transport pathways (air, water, etc.), PFASs used in the manufacture of consumer products eventually enter the human food chain and bioaccumulate in liver tissue, catalyzing various hepatological disease states. Based on these health concerns, the US Environmental Protection Agency (EPA) has set a recommended combined concentration of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonate (PFOS), two of the most widely used PFASs, in drinking water at <70 ng L−1 (70 ppt). Current analytical methods for the quantification of PFASs rely on chromatographic separation followed by mass spectrometric analysis. Although such methods are considered the “gold standard” based on their sensitivity and specificity, the instrumental architecture required confines such analyses to a dedicated laboratory environment. Therefore, alternative analytical techniques, such as spectroscopy and electrochemistry, are being actively explored to provide point-of-use, in-field sensors for PFASs. This chapter highlights the main analytical pathways used to quantify PFASs in aqueous matrices, namely chromatography coupled with spectrometry, spectroscopy, and electrochemistry. Each technique is discussed based on its specificity, sensitivity, and portability, followed by a discussion of critical limitations. Finally, we provide a future outlook, emphasizing the importance of commercially viable, portable PFAS detection technologies to enable citizen scientists.