Advanced Analytical Strategy for PFAS Detection and Comprehensive Screening of Volatile Contaminants in Environmental Water Samples

Per- and polyfluoroalkyl substances (PFAS) represent a huge group of anthropogenic compounds used since the discovery of fluoropolymers such as polytetrafluoroethylene (PTFE). Commonly they are known as "forever chemicals," because of their chemical structure: they consist of a carbon chain in which the hydrogen atoms can be fully (per-) or partially (poly-) replaced by fluorine atoms. This structural formula results in exceptionally strong carbon–fluorine bonds, which grant PFAS high thermal and chemical stability, making them resistant to degradation in the environment. Moreover, the presence of a functional group at one end of the molecule imparts surfactant-like behavior. Due to these incredible properties PFAS are extensively used in a variety of industrial and consumer products (food packaging, personal care products, non-stick coatings, cleaning products). However, the same stability leads them to their environmental persistence, bioaccumulation and mobility. Given their potential toxicological impacts and widespread distribution, the development of reliable methods for sample preparation and analysis is essential for effective environmental monitoring. In this study, an innovative analytical strategy was developed, combining dynamic headspace extraction (DHS) and thermal desorption (TD) with one-dimensional and two-dimensional gas chromatography coupled to timeof-flight mass spectrometry (GC-TOFMS). This setup enables accurate quantification of volatile and semivolatile PFAS in aqueous samples, while also allowing non-targeted screening of a broad spectrum of other environmental contaminants. The method was optimized and validated for nine target PFAS, including fluorotelomer alcohols (FTOHs), fluorotelomer acrylates (FTAc), and alkyl sulfonamides (FOSA, FOSE). Three adsorbent materials—Tenax TA, Carbotrap T420, and Carbotrap 202—as well as three extraction volumes (1 L, 2 L, and 5 L) were evaluated. Among these, Tenax TA showed the best performance in terms of recovery and repeatability, while the 1 L extraction volume provided the most consistent and reliable results. The optimized method demonstrated high sensitivity, achieving detection limits as low as 2.17 ng/L. To assess its real-world applicability, the method was applied to an industrial wastewater sample, where GC×GC-TOFMS enabled the identification of 115 additional environmentally relevant compounds, including halogenated species, monoaromatics, and polycyclic aromatic hydrocarbons. Overall, the combined DHS-TD-GC×GC-TOFMS approach offers a powerful analytical solution for both targeted PFAS detection and comprehensive screening of other (semi-)volatile pollutants in environmental samples, providing a reliable tool for the environmental monitoring.