Mechanisms and potential applications of technologies for detecting specific polyfluoroalkyl substances via nano-level interactions

Abstract

Per- and polyfluoroalkyl substances, possessing chemically and thermally stable C–F bonds, have been widely used in various products owing to their flame retardancy, chemical resistance, and water- and oil-repellent characteristics. Among these, some perfluoroalkyl substances (‘specific PFASs’) are beginning to raise concerns regarding their potential toxicity to living organisms and bioaccumulation. Recently, specific PFASs originating from fire-extinguishing foam, wastewater from semiconductor manufacturing plants, and fluororesin-coated waste have been detected in aqueous environments worldwide. These species are mainly present at low concentrations (parts-per-trillion (ppt) level) and have prompted stringent regulations, such as drinking water standards. Liquid chromatography–tandem mass spectrometry remains the gold standard for detecting specific PFASs at the ppt level. However, its implementation necessitates skilled handling and long analysis durations. To address these problems, based on interactions with specific PFASs at the nano-level, there has been active development of materials aimed at detecting specific PFASs with high sensitivity, in a simple manner, and in a short time. Several materials capable of detecting specific PFASs at parts-per-billion (ppb) to parts-per-million (ppm) levels are already undergoing verification research with a view to practical application. Nevertheless, the detection of specific PFASs at the ppt level in actual aqueous environments remains challenging owing to limited selectivity against contaminants and difficulty in widespread on-site detection. This review provides a comprehensive overview of detection materials and technologies for specific PFASs. Moreover, it comprehensively discusses the detection mechanisms and sensing performance of specific PFAS detection materials, as well as issues facing practical application, and presents future prospects for materials and their development aimed at the simple, rapid, and highly sensitive detection of specific PFASs.