Per- and polyfluoroalkyl substances (PFAS) represent a large class of synthetic chemicals that have been in use since the development of fluoropolymers such as PTFE. Often referred to as "forever chemicals," PFAS are characterized by their persistence in the environment, due to their chemical structure. These compounds consist of a carbon chain that is fully or partially fluorinated, giving them exceptional resistance to heat and chemical degradation. Additionally, the presence of a functional group at one end of the molecule provides surfactant properties. While these characteristics make PFAS highly valuable in various industrial applications (including food packaging, water-repellent fabrics, personal care products, non-stick coatings, and cleaning products) the same stability also contributes to their widespread environmental persistence and mobility. Given their toxicological risks, environmental mobility, and tendency to bioaccumulate, reliable methods for sample preparation and analysis are essential for effective environmental monitoring. This study focuses on developing an innovative analytical strategy by combining dynamic headspace extraction (DHS) and thermal desorption (TD) with one-dimensional and two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC-TOFMS). The goal is to accurately quantify volatile and semi-volatile PFAS in water samples. Furthermore, this method enables broad-spectrum screening of other contaminants in aqueous matrices. The technique was optimized and validated for nine selected volatile and semi-volatile PFAS, including fluorotelomer alcohols (FTOHs), fluorotelomer acrylate (FTAc), and alkyl sulfonamides (FOSA, FOSE). During the enrichment process, three different adsorbent materials were tested, with Tenax TA showing the best performance in terms of recovery and repeatability. Among the extraction volumes tested (1 L, 2 L, and 5 L), the 1 L volume yielded the most reliable results. The optimized method demonstrated high sensitivity, with detection limits as low as 2.17 ng/L. In a real-world application involving industrial wastewater, the advanced separation capabilities of GC×GC-TOFMS enabled the identification of 115 additional environmentally significant compounds, including halogenated compounds, monoaromatics, and polycyclic aromatic hydrocarbons. Overall, the integrated DHS-TD-GC×GC-TOFMS approach offers a powerful analytical platform for both targeted PFAS detection and comprehensive screening of other (semi-) volatile contaminants in environmental samples, providing a valuable tool for environmental monitoring efforts.
TD-(GC×)GC-TOFMS: a novel methodology for sampling and analyzing PFAS in water samples
Corviseri M. C.;Polidoro Dos Santos Allan;De Poli M.;Stevanin C.;Pasti L.;Franchina F. A.
2025
Abstract
Per- and polyfluoroalkyl substances (PFAS) represent a large class of synthetic chemicals that have been in use since the development of fluoropolymers such as PTFE. Often referred to as "forever chemicals," PFAS are characterized by their persistence in the environment, due to their chemical structure. These compounds consist of a carbon chain that is fully or partially fluorinated, giving them exceptional resistance to heat and chemical degradation. Additionally, the presence of a functional group at one end of the molecule provides surfactant properties. While these characteristics make PFAS highly valuable in various industrial applications (including food packaging, water-repellent fabrics, personal care products, non-stick coatings, and cleaning products) the same stability also contributes to their widespread environmental persistence and mobility. Given their toxicological risks, environmental mobility, and tendency to bioaccumulate, reliable methods for sample preparation and analysis are essential for effective environmental monitoring. This study focuses on developing an innovative analytical strategy by combining dynamic headspace extraction (DHS) and thermal desorption (TD) with one-dimensional and two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC-TOFMS). The goal is to accurately quantify volatile and semi-volatile PFAS in water samples. Furthermore, this method enables broad-spectrum screening of other contaminants in aqueous matrices. The technique was optimized and validated for nine selected volatile and semi-volatile PFAS, including fluorotelomer alcohols (FTOHs), fluorotelomer acrylate (FTAc), and alkyl sulfonamides (FOSA, FOSE). During the enrichment process, three different adsorbent materials were tested, with Tenax TA showing the best performance in terms of recovery and repeatability. Among the extraction volumes tested (1 L, 2 L, and 5 L), the 1 L volume yielded the most reliable results. The optimized method demonstrated high sensitivity, with detection limits as low as 2.17 ng/L. In a real-world application involving industrial wastewater, the advanced separation capabilities of GC×GC-TOFMS enabled the identification of 115 additional environmentally significant compounds, including halogenated compounds, monoaromatics, and polycyclic aromatic hydrocarbons. Overall, the integrated DHS-TD-GC×GC-TOFMS approach offers a powerful analytical platform for both targeted PFAS detection and comprehensive screening of other (semi-) volatile contaminants in environmental samples, providing a valuable tool for environmental monitoring efforts.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
