Nontarget and Suspect Screening of Fluorinated Ionic Liquids and PFAS in European Wastewaters Using Supercritical Fluid Chromatography

Selina Tisler; Jonathan Zweigle; Maria Kregler Gotil; Saskia Finckh; Werner Brack; Eva Maria Braxmaier; Corina Meyer; Juliane Hollender; Tina Kosjek; Emma L. Schymanski; Pontus Larsson; Anna Kärrman; Erica Selin; Dalia Elabbadi; Harry Elliss; Barbara Kasprzyk-Hordern; Tim Boogaerts; Adrian Covaci; Herbert Oberacher; Harold Flores Quintana; Foon Yin Lai; Lutz Ahrens; Azziz Assoumani; Frederic Béen; Jan H. Christensen

doi:10.1021/acs.est.5c06876

Nontarget and Suspect Screening of Fluorinated Ionic Liquids and PFAS in European Wastewaters Using Supercritical Fluid Chromatography

Selina Tisler, Jonathan Zweigle, Maria Kregler Gotil, Saskia Finckh, Werner Brack, Eva Maria Braxmaier, Corina Meyer, Juliane Hollender, Tina Kosjek, Emma L. Schymanski, Pontus Larsson, Anna Kärrman, Erica Selin, Dalia Elabbadi, Harry Elliss, Barbara Kasprzyk-Hordern, Tim Boogaerts, Adrian Covaci, Herbert Oberacher, Harold Flores QuintanaFoon Yin Lai, Lutz Ahrens, Azziz Assoumani, Frederic Béen, Jan H. Christensen

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1 Citation (SciVal)

Abstract

Per- and polyfluoroalkyl substances (PFAS) and fluorinated ionic liquids were investigated in municipal effluents from 30 wastewater treatment plants (WWTPs) across 15 European countries using supercritical fluid chromatography-high-resolution mass spectrometry (SFC-HRMS) for nontarget screening. Bis-perfluoroalkyl sulfonimide (bis-FASI) ionic liquids were detected as bis(trifluoromethanesulfonyl)imide (NTf2-), two rarely reported homologues (±2 CF2, namely FSI- and BETI-), and two previously unreported homologues (±1 CF2, namely FTFSI- and FTNTf2-). Bis-FASIs were present in 85% of samples and were more abundant in effluents from larger WWTPs. The fluorinated anion PF6-, commonly used in ionic liquids, was found in all samples (≤3 μg/L). Hexafluoroarsenate (AsF6-), reported here for the first time in municipal wastewater, was detected in 32% of samples in eight countries. PF6- and AsF6- concentrations exceeded those of traditional PFSAs and PFCAs in 97% of the samples. No removal was detected for perfluorinated compounds, inorganic anions, and low-fluorinated pharmaceuticals and pesticides. Low-fluorinated substances were detected in 90% of samples (>100 ng/L), yet PF6- alone surpassed the combined concentration of all low-fluorinated substances in 27 out of 30 samples. These results reveal the significance of unconventional fluorinated substances for the overall fluorine load in wastewater, highlighting the need to extend monitoring strategies beyond legacy PFAS.

Original language	English
Pages (from-to)	21300-21311
Number of pages	12
Journal	Environmental Science & Technology
Volume	59
Issue number	39
Early online date	28 Sept 2025
DOIs	https://doi.org/10.1021/acs.est.5c06876
Publication status	Published - 7 Oct 2025

Funding

This work was carried out in the framework of the European Partnership for the Assessment of Risks from Chemicals (PARC) and has received funding from the European Union’s Horizon Europe research and innovation program under Grant Agreement No 101057014. Views and opinions expressed are, however, those of the author(s) only and do not necessarily reflect those of the European Union or the Health and Digital Executive Agency. Neither the European Union nor the granting authority can be held responsible for them. TB was cofinanced by Research Foundation Flanders (Grant number: 1225924N). Additionally, we would like to acknowledge the stakeholders (WWTP operators), especially Vand Center Syd (Denmark), Aquafin (Belgium), water board de Dommel and HDSR (Netherlands), Rey Eyer and Jörg Ringwald (Switzerland), Jörg Ahlheim and Margit Petre (Germany), Tomas Mackulak (Slovakia), Wessex Water staff and Megan Robertson and John Bagnall (Great Britain), Bilbao-Bizkaia Water Council and Iñigo Gonzalez (Spain), Theodor Crispin and Västra Mälardalens Energi och Miljö AB (Sweden). Noelia Salgueiro Gonzalez and Sara Castiglioni (Mario Negri Institute for Pharmacological Research, Milan, Italy) are acknowledged for collection, extraction and metadata gathering of samples from Italy.

Keywords

bis-FASIs
fluorine mass balance
hexafluorophosphate
inorganic fluorinated compounds
ultrashort-chain PFAS

ASJC Scopus subject areas

General Chemistry
Environmental Chemistry

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Tisler, S., Zweigle, J., Gotil, M. K., Finckh, S., Brack, W., Braxmaier, E. M., Meyer, C., Hollender, J., Kosjek, T., Schymanski, E. L., Larsson, P., Kärrman, A., Selin, E., Elabbadi, D., Elliss, H., Kasprzyk-Hordern, B., Boogaerts, T., Covaci, A., Oberacher, H., ... Christensen, J. H. (2025). Nontarget and Suspect Screening of Fluorinated Ionic Liquids and PFAS in European Wastewaters Using Supercritical Fluid Chromatography. Environmental Science & Technology, 59(39), 21300-21311. https://doi.org/10.1021/acs.est.5c06876

Tisler, S, Zweigle, J, Gotil, MK, Finckh, S, Brack, W, Braxmaier, EM, Meyer, C, Hollender, J, Kosjek, T, Schymanski, EL, Larsson, P, Kärrman, A, Selin, E, Elabbadi, D , Elliss, H , Kasprzyk-Hordern, B, Boogaerts, T, Covaci, A, Oberacher, H, Flores Quintana, H, Lai, FY, Ahrens, L, Assoumani, A, Béen, F & Christensen, JH 2025, 'Nontarget and Suspect Screening of Fluorinated Ionic Liquids and PFAS in European Wastewaters Using Supercritical Fluid Chromatography', Environmental Science & Technology, vol. 59, no. 39, pp. 21300-21311. https://doi.org/10.1021/acs.est.5c06876

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title = "Nontarget and Suspect Screening of Fluorinated Ionic Liquids and PFAS in European Wastewaters Using Supercritical Fluid Chromatography",

abstract = "Per- and polyfluoroalkyl substances (PFAS) and fluorinated ionic liquids were investigated in municipal effluents from 30 wastewater treatment plants (WWTPs) across 15 European countries using supercritical fluid chromatography-high-resolution mass spectrometry (SFC-HRMS) for nontarget screening. Bis-perfluoroalkyl sulfonimide (bis-FASI) ionic liquids were detected as bis(trifluoromethanesulfonyl)imide (NTf2-), two rarely reported homologues (±2 CF2, namely FSI- and BETI-), and two previously unreported homologues (±1 CF2, namely FTFSI- and FTNTf2-). Bis-FASIs were present in 85\% of samples and were more abundant in effluents from larger WWTPs. The fluorinated anion PF6-, commonly used in ionic liquids, was found in all samples (≤3 μg/L). Hexafluoroarsenate (AsF6-), reported here for the first time in municipal wastewater, was detected in 32\% of samples in eight countries. PF6- and AsF6- concentrations exceeded those of traditional PFSAs and PFCAs in 97\% of the samples. No removal was detected for perfluorinated compounds, inorganic anions, and low-fluorinated pharmaceuticals and pesticides. Low-fluorinated substances were detected in 90\% of samples (>100 ng/L), yet PF6- alone surpassed the combined concentration of all low-fluorinated substances in 27 out of 30 samples. These results reveal the significance of unconventional fluorinated substances for the overall fluorine load in wastewater, highlighting the need to extend monitoring strategies beyond legacy PFAS.",

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AU - Tisler, Selina

AU - Zweigle, Jonathan

AU - Gotil, Maria Kregler

AU - Finckh, Saskia

AU - Brack, Werner

AU - Braxmaier, Eva Maria

AU - Meyer, Corina

AU - Hollender, Juliane

AU - Kosjek, Tina

AU - Schymanski, Emma L.

AU - Larsson, Pontus

AU - Kärrman, Anna

AU - Selin, Erica

AU - Elabbadi, Dalia

AU - Elliss, Harry

AU - Kasprzyk-Hordern, Barbara

AU - Boogaerts, Tim

AU - Covaci, Adrian

AU - Oberacher, Herbert

AU - Flores Quintana, Harold

AU - Lai, Foon Yin

AU - Ahrens, Lutz

AU - Assoumani, Azziz

AU - Béen, Frederic

AU - Christensen, Jan H.

PY - 2025/10/7

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N2 - Per- and polyfluoroalkyl substances (PFAS) and fluorinated ionic liquids were investigated in municipal effluents from 30 wastewater treatment plants (WWTPs) across 15 European countries using supercritical fluid chromatography-high-resolution mass spectrometry (SFC-HRMS) for nontarget screening. Bis-perfluoroalkyl sulfonimide (bis-FASI) ionic liquids were detected as bis(trifluoromethanesulfonyl)imide (NTf2-), two rarely reported homologues (±2 CF2, namely FSI- and BETI-), and two previously unreported homologues (±1 CF2, namely FTFSI- and FTNTf2-). Bis-FASIs were present in 85% of samples and were more abundant in effluents from larger WWTPs. The fluorinated anion PF6-, commonly used in ionic liquids, was found in all samples (≤3 μg/L). Hexafluoroarsenate (AsF6-), reported here for the first time in municipal wastewater, was detected in 32% of samples in eight countries. PF6- and AsF6- concentrations exceeded those of traditional PFSAs and PFCAs in 97% of the samples. No removal was detected for perfluorinated compounds, inorganic anions, and low-fluorinated pharmaceuticals and pesticides. Low-fluorinated substances were detected in 90% of samples (>100 ng/L), yet PF6- alone surpassed the combined concentration of all low-fluorinated substances in 27 out of 30 samples. These results reveal the significance of unconventional fluorinated substances for the overall fluorine load in wastewater, highlighting the need to extend monitoring strategies beyond legacy PFAS.

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KW - bis-FASIs

KW - fluorine mass balance

KW - hexafluorophosphate

KW - inorganic fluorinated compounds

KW - ultrashort-chain PFAS

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Nontarget and Suspect Screening of Fluorinated Ionic Liquids and PFAS in European Wastewaters Using Supercritical Fluid Chromatography

Abstract

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Keywords

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