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Cited by 346Per- and polyfluoroalkyl substances researchFluorine in Organic ChemistryMass Spectrometry Techniques and Applications

High-resolution mass spectrometry (HRMS) methods for nontarget discovery and characterization of poly- and per-fluoroalkyl substances (PFASs) in environmental and human samples

Open access
Liu, Yanna, D'Agostino, Lisa A., Qu, Guangbo, Jiang, Guibin, Martin, Jonathan W.·2019·TrAC Trends in Analytical Chemistry
DOI 10.1016/j.trac.2019.02.021
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Abstract

Widespread environmental contamination of legacy long-chain poly- and per-fluoroalkyl substances (PFASs) has triggered chemical regulatory action and a global transitioning to alternative PFASs. More than 5000 PFASs are now recognized on various lists, but few have been monitored despite ample evidence of unidentified organic fluorine in human and environmental samples. Nevertheless, our review of the literature indicates that nontarget analytical methods based on high-resolution mass spectrometry have been used to discover more than 750 PFASs, belonging to more than 130 diverse classes, in strategically selected environmental samples, biofluids or commercial products. Among these reports, we summarize the analytical and data-processing strategies for nontarget PFAS discovery, identify knowledge gaps and propose new areas for method development. Discovery of emerging PFASs before they are global contaminants could mitigate future contamination if strategic techniques can be developed to prioritize some of these substances for synthesis and confirmation, further monitoring, source elucidation and hazard characterization.

Verified 2026-10-06 · 2 references not checked yet

AI snapshot

Written from the paper’s full text.

TL;DR

This review summarizes HRMS-based nontarget and suspect workflows for discovering and characterizing PFASs in environmental and human samples, covering sample preparation, chromatography, acquisition, data filtering, formula assignment, and structural confirmation. It reports that nontarget HRMS has revealed hundreds of previously unrecognized PFASs and highlights that most identifications remain tentative without authentic standards.

Key findings

  • Nontarget HRMS studies have discovered more than 750 PFAS analytes in more than 130 classes; PFCAs, PFSAs, FTs, and PFSMs combined make up 82% of discovered PFAS classes and 74% of analytes, and the conclusions state that ~980 new PFAS analytes have been proposed in less than a decade (not considering branched isomers).
  • Unknown organic fluorine is substantial: 50% to >99% in environmental samples and 15% to >99% in biological samples; in TOP assays, known PFAS precursors accounted for only 23% in urban run-off water, 3–18% in wastewater, 60% in AFFF-impacted groundwater, and 18–82% in river water.
  • PFAS feature filtering commonly uses mass defect, homologous series/CF₂-normalized mass defect plots, diagnostic fluorine-containing fragments or neutral losses, and study design; RP ≥60,000 is recommended for reliable formula assignment for C,H,O,N,F,P compounds, and RP ≥100,000 to resolve the 3.37 mDa split between C₃ and H₄S.
  • Most published nontarget PFAS identifications are confidence level 2–3 because authentic standards are rarely available; suspect screening databases exist, but at least 1000 of the ~5000 PFASs listed in public databases have no molecular formula and/or structural information.

Methods

  • Narrative review of analytical methods and data-processing strategies for nontarget PFAS discovery by HRMS, including literature available online up to October 31, 2018.
  • Surveyed published nontarget PFAS discovery studies in commercial products, environmental matrices (water, sediment, soil, airborne particulate matter, concrete), and biological matrices (fish liver, polar bear, human serum), summarized in Tables 1 and 2.
  • Synthesized workflows for sample preparation, LC/GC separation, HRMS acquisition (TOF, Orbitrap, FTICR), feature filtering, molecular formula assignment, MSⁿ structural characterization, suspect screening, and confidence-level reporting.

Limitations

  • Stated: many identifications remain tentative and must be followed by authentic chemical standard synthesis, further targeted and quantitative monitoring, and toxicology; most published nontarget PFAS identifications are in the confidence level 2–3 range.
  • Stated: total PFAS discovery counts may be underestimated because unresolved structural isomers from electrochemical fluorination and coelution can mask distinct analytes; at least 1000 of the ~5000 PFASs in public databases lack molecular formula and/or structural information.
  • Evident: as a review, it presents no new experimental data or primary validation, and the literature survey is not described as a systematic review with formal search and inclusion criteria.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1016/j.trac.2019.02.021

Cites

69 of 71 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 68 cited sources checked · 0 supported · 0 flagged

  • Findingnone given

    The discovered PFASs include other structures such as per/polyfluoroalkyl phosphates, per/polyfluoroalkyl alcohols, per/polyfluoroalkylamides, per/polyfluoroalkyl sulfates, and N-per/polyfluoroalkyls.

    “Other structures include per/polyfluoroalkyl phosphates, per/polyfluoroalkyl alcohols, per/polyfluoroalkylamides, per/polyfluoroalkyl sulfates and N-per/polyfluoroalkyls.”
    Quote in the paperNot a substantial claim
  • Findingnone given

    New PFASs are usually structurally very similar to legacy PFASs, with slight modifications including H- and Cl-substitution, ether-, thioether and double-bond/ring functionality insertion, and/or variations on non-fluorinated polar head groups.

    “These new PFASs are usually of structures very similar to legacy PFASs, with slight modifications, including H-and Clsubstitution, ether-, thioether and double-bond/ring functionality insertion, and/or variations on non-fluorinated polar head groups.”
    Quote in the paperNot a substantial claim
  • Findingnone given

    In less than a decade, the scientific community has detected and proposed structures for ~980 new PFAS analytes (not considering associated branched isomers).

    “in less than a decade the scientific community has detected and proposed structures for ~980 new PFAS analytes (not considering associated branched isomers) (Tables 1 and 2).”
    Quote in the paperSubstantial claim
  • Findingreasoning

    Many PFAS identifications from nontarget HRMS remain tentative.

    “many identifications remain tentative”
    Quote in the paperSubstantial claim
  • Premisecitation

    High sensitivity allows detection of some trace contaminants at femtogram levels in full-scan operation.

    “Other important advances include fast fullscanning rates (i.e.>1 Hz), which allows for on-line coupling to chromatography, and high sensitivity, thereby allowing detection of some trace contaminants at femtogram levels in full-scan operation.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [24] Krauss, 2010, LC-high resolution MS in environmental analysis: from target screening to the identification of unknowns, Anal. Bioanal. Chem. source

      Not checked in the free run.

  • May combine two claims. 23
  • Classified as probably not a substantial claim. 9

  • May combine two claims.

    Findingnone given

    PFCAs, PFSAs, FTs and PFSMs combined compose 82% of all discovered PFAS classes and 74% of all PFAS analytes.

    “PFCAs, PFSAs, FTs and PFSMs combined compose 82% of all discovered PFAS classes, and 74% of all PFAS analytes.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingnone given

    More than 750 PFAS analytes in more than 130 classes have been discovered and reported, containing PFAS moieties ranging from C2F4 to C44F79.

    “In total, more than 750 PFAS analytes in more than 130 classes have been discovered and reported containing PFAS moieties ranging from small (e.g.C 2 F 4 ) to very large (e.g.C 44 F 79 ) (Table 1).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Higher mass spectral resolving power reduces interferences and may reveal minor features.

    “This is largely thanks to a combination of higher mass spectral resolving power (RP), which reduces interferences and may reveal minor features, and high mass accuracy, which allows prediction of molecular formulas for the spectral peaks.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [24] Krauss, 2010, LC-high resolution MS in environmental analysis: from target screening to the identification of unknowns, Anal. Bioanal. Chem. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Since the early 2000s, there has been a slow global trend towards regulatory restrictions or bans on long-chain PFAAs and their precursor PFASs, with a shift to alternative PFASs.

    “Since their discovery as global contaminants in the early 2000s [2,6], there has been a slow global trend towards regulatory restrictions or bans on long-chain PFAAs and their precursor PFASs (e.g.Stockholm Convention [7]), with a concomitant shift to alternative PFASs [8].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [7] Stockholm-Convention, 2009

      Not checked in the free run.

    • cites [8] OECD, 2015

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Some recent discoveries are legacy substances likely present in the environment for more than 40 years already.

    “Among such recent contaminant discoveries, some are PFAA-precursors (e.g.perfluorooctaneamido quaternary ammonium salt [32]) that could contribute to environmental PFAA exposure for years to come [45], some are legacy substances likely present in the environment for more than 40 years already (e.g.chlorinated perfluoroether sulfonates [42]), while others are likely new current-use alternatives (e.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [42] Liu, 2018, Nontarget mass spectrometry reveals new perfluoroalkyl substances in fish from the Yangtze River and Tangxun Lake, China, Environ. Sci. Technol. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Long-chain perfluorinated acids (PFAAs) are of particular concern due to their environmental persistence, high bioaccumulation potentials, and associated toxicities.

    “Long-chain perfluorinated acids (PFAAs) are of particular concern due to their combinations of environmental persistence, high bioaccumulation potentials, and associated toxicities [1].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [1] OECD, 2013

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Nontarget HRMS analysis has been applied in molecular life sciences and petroleomics, and has recently gained popularity in environmental analytical chemistry.

    “Nontarget HRMS analysis has been applied in molecular life sciences [27] and in petroleomics [28], and has most recently gained popularity in environmental analytical chemistry due to the above mentioned advances.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [27] Brown, 2005, Metabolomics applications of FT-ICR mass spectrometry, Mass Spectrom. Rev. source

      Not checked in the free run.

    • cites [28] Marshall, 2008, Petroleomics: chemistry of the underworld, Proc. Natl. Acad. Sci. U. S. A. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Commercially available HRMS instruments include TOF-MS with RP >20,000, mass accuracy 3 ppm and scan rate up to 500 Hz; Orbitrap-MS with RP >100,000, mass accuracy 2 ppm and scan rate up to 40 Hz; and FTICR-MS with RP >1,000,000, mass accuracy 1 ppm and scan rate 1 Hz.

    “Commercially available HRMS instruments include various time-of-flight instruments (TOF-MS, RP !20,000, mass accuracy 3 ppm, scan rate up to 500 Hz [25]), Orbitrap (Orbitrap-MS, !100,000; 2 ppm; up to 40 Hz [26]) and Fouriertransform ion cyclotron resonance (FTICR-MS, !1,000,000; 1 ppm; 1 Hz) [24].”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [24] Krauss, 2010, LC-high resolution MS in environmental analysis: from target screening to the identification of unknowns, Anal. Bioanal. Chem. source

      Not checked in the free run.

    • cites [25] Lacorte, 2006, Time of flight mass spectrometry applied to the liquid chromatographic analysis of pesticides in water and food, Mass Spectrom. Rev. source

      Not checked in the free run.

    • cites [26] Thermo-Scientific, 2018

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    PFASs are man-made chemicals that have been used for almost 70 years, and some have been identified as global contaminants since 2001.

    “Per-and poly-fluoroalkyl substances (PFASs) are a general class of man-made chemicals that have been used for almost 70 years, but only since 2001 have some of these been identified as global contaminants [1,2].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [1] OECD, 2013

      Not checked in the free run.

    • cites [2] Giesy, 2001, Global distribution of perfluorooctane sulfonate in wildlife, Environ. Sci. Technol. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The two main categories of alternative PFASs under ongoing production are short-chain PFAS analogues and structurally modified legacy PFASs, such as perfluoroalkyl ether acids.

    “According to limited public information, the two main categories of alternative PFASs under ongoing production are the shortchain PFAS analogues, and structurally modified legacy PFASs (e.g.perfluoroalkyl ether acids) [1].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [1] OECD, 2013

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Hypothesis-driven targeted analytical approaches have had success in the past, but are historically slow and may not be feasible given over 5000 PFASs recognized today.

    “Hypothesis-driven targeted analytical approaches have had success in the past [22], but this is historically a slow process and may not be feasible given over 5000 PFASs that are recognized today [23].”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [22] Martin, 2002, Collection of airborne fluorinated organics and analysis by gas chromatography/chemical ionization mass spectrometry, Anal. Chem. source

      Not checked in the free run.

    • cites [23] USEPA, 2018

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    C18 analytical column chemistries were employed for separations prior to nontarget mass spectrometry in almost all studies reviewed, with the only exception being a C8 column used in one study.

    “C18 analytical column chemistries were employed for separations prior to nontarget mass spectrometry in almost all studies reviewed (Table 2), with the only exception being a C8 column used in one study [35].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [35] Strynar, 2015, Identification of novel perfluoroalkyl ether carboxylic acids (PFECAs) and sulfonic Acids (PFESAs) in natural waters using accurate mass time-of-flight mass spectrometry (TOFMS), Environ. Sci. Technol. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Substantial direct evidence of unresolved structural isomers from electrochemical fluorination has been observed in some nontarget studies with chromatography, but other studies used infusion which masks isomers for each distinct homologue.

    “Substantial direct evidence of such isomers has been observed in some nontarget studies with chromatography [30,31,42] (Table 2), but others used infusion which masks any isomers for each distinct homologue.”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [30] D'Agostino, 2014, Identification of novel fluorinated surfactants in aqueous film forming foams and commercial surfactant concentrates, Environ. Sci. Technol. source

      Not checked in the free run.

    • cites [31] Barzen-Hanson, 2017, Discovery of 40 classes of per- and polyfluoroalkyl substances in historical aqueous film-forming foams (AFFFs) and AFFF-impacted groundwater, Environ. Sci. Technol. source

      Not checked in the free run.

    • cites [42] Liu, 2018, Nontarget mass spectrometry reveals new perfluoroalkyl substances in fish from the Yangtze River and Tangxun Lake, China, Environ. Sci. Technol. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Liu et al. [38] detected highly complex MS/MS spectra for some PFAS classes in fish liver extracts, which likely indicate isomer coelutions.

    “For example, Liu et al. [38] detected highly complex MS/MS spectra for some PFAS classes in fish liver extracts, which likely indicate isomer coelutions.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [38] Lin, 2017, Identification of novel hydrogen-substituted polyfluoroalkyl ether sulfonates in environmental matrices near metal-plating facilities, Environ. Sci. Technol. source

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    Both unresolved structural isomers and coelution may lead to an underestimation of the true numbers of PFAS analytes already detected.

    “Both factors may lead to an underestimation of the true numbers of PFAS analytes already detected.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: Coelution may occur even with chromatographic separation.

  • May combine two claims.

    Interpretationreasoning

    Nontarget analysis is still advantageous for PFAS screening because at least 1000 of the ~5000 PFASs listed in public databases lack molecular formula and/or structural information.

    “Nevertheless, at least 1000 of the ~5000 PFASs listed in public databases have no molecular formula and/or structural information, thus nontarget analysis is still advantageous for PFAS screening.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: At least 1000 of the ~5000 PFASs listed in public databases have no molecular formula and/or structural information.

  • May combine two claims.

    Premisenone given

    Without chromatographic separation, spectral interpretation is much more challenging and could lead to incorrect structural assignments.

    “Without chromatographic separation, spectral interpretation is a much more challenging task and could lead to incorrect structural assignments.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisereasoning

    Ion mobility separation can be particularly useful for differentiating among isobars, isomers or even enantiomers.

    “Ion mobility separation can be particularly useful for differentiating among isobars, isomers or even enantiomers.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Combustion ion chromatography (CIC) and particle-induced gamma ray emission (PIGE) can both measure total fluorine content in various sample types.

    “For example, combustion ion chromatography (CIC) [14] and particle-induced gamma ray emission (PIGE) [56] can both measure total fluorine content in various sample types.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [14] Miyake, 2007, Determination of trace levels of total fluorine in water using combustion ion chromatography for fluorine: a mass balance approach to determine individual perfluorinated chemicals in water, J. Chromatgr. A source

      Not checked in the free run.

    • cites [56] Ritter, 2017, PIGE as a screening tool for Per- and polyfluorinated substances in papers and textiles, Nucl. Instrum. Methods B source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    PFAS extraction from water and urine using fluorinated solvents, such as perfluorotertbutanol, has been explored and reduced matrix effects were evident compared to WAX SPE.

    “PFAS extraction from water and urine using fluorinated solvents, such as perfluorotertbutanol [54], has been explored and reduced matrix effects were evident compared to WAX SPE.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [54] Wang, 2018, A highly selective dispersive liquid-liquid microextraction approach based on the unique fluorous affinity for the extraction and detection of per- and polyfluoroalkyl substances coupled with high performance liquid chromatography tandem-mass spectrometry, J. Chromatogr. A source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Most nontarget PFAS discovery studies have been performed under negative electrospray ionization mode, thereby revealing new anionic PFASs.

    “Most studies have been performed under negative electrospray ionization mode [32,34e38,40e42,44] (Table 2), thereby revealing new anionic PFASs (Table 1).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [32,34e38,40e42,44]

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Chromatography can help separate PFAS isomers, thereby maximizing discovery potential and revealing mass spectra of pure compounds.

    “Moreover, commercially relevant PFASs are often composed of multiple structural isomers (i.e. with the same exact mass) [5,59], thus the use of chromatography can also help to separate isomers [31,42], thereby maximizing the discovery potential and revealing mass spectra of pure compounds.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [31] Barzen-Hanson, 2017, Discovery of 40 classes of per- and polyfluoroalkyl substances in historical aqueous film-forming foams (AFFFs) and AFFF-impacted groundwater, Environ. Sci. Technol. source

      Not checked in the free run.

    • cites [42] Liu, 2018, Nontarget mass spectrometry reveals new perfluoroalkyl substances in fish from the Yangtze River and Tangxun Lake, China, Environ. Sci. Technol. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    TOF, Orbitrap, and FTICR are three HRMS technologies already proven as useful tools in PFAS discovery.

    “TOF [29e32,35,39e41], Orbitrap [34,37,38,42] and Fouriertransform ion cyclotron resonance (FTICR) [30] are three HRMS technologies already proven as useful tools in PFAS discovery.”
    Quote in the paperNot a substantial claim0 of 6 sources checked
    • cites [29e32,35,39e41]

      Not checked in the free run.

    • cites [34] Liu, 2015, Discovery of C5-C17 poly- and perfluoroalkyl substances in water by in-line SPE-HPLC-Orbitrap with in-source fragmentation flagging, Anal. Chem. source

      Not checked in the free run.

    • cites [37] Gebbink, 2017, Presence of emerging per- and polyfluoroalkyl substances (PFASs) in river and drinking water near a fluorochemical production plant in The Netherlands, Environ. Sci. Technol. source

      Not checked in the free run.

    • cites [38] Lin, 2017, Identification of novel hydrogen-substituted polyfluoroalkyl ether sulfonates in environmental matrices near metal-plating facilities, Environ. Sci. Technol. source

      Not checked in the free run.

    • cites [42] Liu, 2018, Nontarget mass spectrometry reveals new perfluoroalkyl substances in fish from the Yangtze River and Tangxun Lake, China, Environ. Sci. Technol. source

      Not checked in the free run.

    • cites [30] D'Agostino, 2014, Identification of novel fluorinated surfactants in aqueous film forming foams and commercial surfactant concentrates, Environ. Sci. Technol. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Pairing HPLC to on-line SPE had multiple benefits including high speed, high recovery, minimizing contamination, and high sensitivity by allowing large volumes to be extracted and immediately directed to the HPLC-HRMS instrument.

    “This had multiple related benefits, including high speed, high recovery, minimizing contamination, and high sensitivity by allowing large volumes to be extracted and immediately directed (up to 5 mL) to the HPLC-HRMS instrument [34].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [34] Liu, 2015, Discovery of C5-C17 poly- and perfluoroalkyl substances in water by in-line SPE-HPLC-Orbitrap with in-source fragmentation flagging, Anal. Chem. source

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    Recent advances in HRMS make discovery of unknown or suspect PFASs in human or environmental samples possible without immediate need for authentic standards, allowing their discovery earlier in the chemical life-cycle, possibly at the source before they become globally distributed.

    “Recent advances in HRMS make discovery of unknown or suspect PFASs in human or environmental samples possible without immediate need for authentic standards, thereby allowing their discovery earlier in the chemical life-cycle, possibly at the source before they become globally distributed.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Liu et al. [42] tentatively proposed a new class of perfluorinated N-heterocycles in fish liver with a confidence level of 3.

    “For example, despite more than 5000 known PFASs in all available databases, Liu et al. [42] tentatively proposed a new class of perfluorinated N-heterocycles in fish liver with a confidence level of 3.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [42] Liu, 2018, Nontarget mass spectrometry reveals new perfluoroalkyl substances in fish from the Yangtze River and Tangxun Lake, China, Environ. Sci. Technol. source

      Not checked in the free run.

  • May combine two claims.

    Premisenone given

    Both CIC and PIGE have low sensitivity, limiting their direct application to many environmental samples.

    “Both CIC and PIGE, however, have low sensitivity, limiting their direct application to many environmental samples.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisereasoning

    Chromatographic separation benefits nontarget discovery by separating matrix components from analytes, improving sensitivity by removal of matrix effects, and minimizing isobaric interferences.

    “Chromatographic separation inherently benefits nontarget discovery by separating matrix components from analytes of interest, thereby improving sensitivity by removal of matrix effects and minimizing isobaric interferences.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data

    The authors surveyed the published literature up to October 31, 2018, to summarize PFASs discovered by nontarget HRMS techniques covered in the review.

    “We surveyed the published literature to date (October 31, 2018) and summarized the PFASs that have been discovered by techniques covered in this review.”
    Quote in the paperNot a substantial claim
29 of 29

  • The paper relies on this without support.

    Suspect screening does not require the immediate availability of authentic standards.

    “Suspect screening does not require the immediate availability of authentic standards”

  • The paper relies on this without support.

    Suspect screening can allow progression from confidence level 3 to confidence level 2 in structural proposals.

    “can allow progression from confidence level 3 to confidence level 2 in structural proposals”

  • The paper relies on this without support.

    Suspect screening can be used for rapidly screening many samples.

    “can be used for rapidly screening many samples”

  • The paper relies on this without support.

    At least 1000 of the ~5000 PFASs listed in public databases have no molecular formula and/or structural information.

    “at least 1000 of the ~5000 PFASs listed in public databases have no molecular formula and/or structural information”

  • The paper relies on this without support.

    Comprehensive nontarget workflows are able to discover potential PFAS transformation products, manufacturing impurities, or PFASs not in available databases.

    “comprehensive nontarget workflows are able to discover potential PFAS transformation products, manufacturing impurities, or PFASs not in available databases”

  • The paper relies on this without support.

    Coelution may occur even with chromatographic separation.

    “coelution may occur even with chromatographic separation”

  • The paper relies on this without support.

    Historical hypothesis-driven targeted analysis has made great contributions to PFAS discovery and to quantification of concentrations in human and environmental samples.

    “Historical hypothesis-driven targeted analysis with sensitive and highly specific analytical methods have made great contributions to PFAS discovery and to quantification of concentrations in human and environmental samples.”

  • The paper relies on this without support.

    Targeted analysis methods have limitations and cannot keep pace with the number of historic and emerging PFASs in the market place.

    “such methods have limitations and cannot keep pace with the number of historic and emerging PFASs in the market place”
8 of 8

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • The frequent detection of 6:2 FTS as a replacement compound raises concerns about the environmental behavior and toxicity of such substitutes, which may not be fully understood or regulated.

    “its frequent detection raises concerns about the environmental behavior and toxicity of such substitutes, which may not be fully understood or regulated.”

    From Integrated Targeted and Suspect Screening Workflow for Identifying PFAS of Concern in Urban-Impacted Serbian Rivers (2026) · cites this paper as [31]

    The Introduction (page unavailable) says information on alternative PFASs is limited and raises concerns about their persistence, toxicity, environmental behavior, and health risks. It does not establish that 6:2 FTS is frequently detected, nor does it specifically address whether that substitute is regulated. (LLM, conf=0.84)

    Experimental — accuracy not yet measured

  • Suspect and nontarget analysis using HRMS has been shown to be a viable and reliable method for screening and identifying emerging PFAS.

    “Suspect and nontarget analysis using high-resolution mass spectrometry (HRMS) has been shown to be a viable and reliable method for screening and identifying emerging PFAS”

    From Molecular characteristics of emerging perfluoroalkyl and polyfluoroalkyl substances (PFAS) and dissolved organic matter (DOM) in surface waters around fluorine-related industries in a Chinese Megacity (2025) · cites this paper as Liu et al., 2019

    Section 5 describes suspect screening as useful for rapidly screening samples and nontarget HRMS as advantageous for discovering PFASs. But Section 4.5 says most published nontarget identifications are probable or tentative and that structural confirmation requires an authentic standard or NMR. The claim’s unqualified description of identification as reliable overstates the source. (LLM, conf=0.86)

    Experimental — accuracy not yet measured

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Rotander et al. class count is reversed in the text

    Minor

    The studies are named in Rotander-Baduel-Yu order, so the text assigns 10 classes to Rotander et al.; Table 2 assigns that study 3 classes.

  • Xiao et al. class count differs between text and Table 2

    Minor

    The text says Xiao et al. identified 12 classes of new PFASs, while Table 2 lists 11 classes for the same study.

  • 140,000-resolution instrument is misidentified as FTICR

    Minor

    The text attributes the 140,000 resolving-power example in reference [37] to FTICR, but Table 2 identifies the instrument for that study as a Q-Exactive.

  • Baduel et al. class count differs between text and Table 2

    Minor

    The text assigns 3 classes to Baduel et al. in its stated study order, whereas Table 2 lists 10. The Rotander and Baduel counts appear to have been interchanged.

4 of 4

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Authors
Liu, Y., D'Agostino, L. A., Qu, G., Jiang, G., & Martin, J. W.
Affiliations
  • University of Alberta (CA)
  • Chinese Academy of Sciences (CN)
  • Stockholm University (SE)
Corresponding author
Qu, Guangbo
ORCID
Venue
TrAC Trends in Analytical Chemistry
Publisher
Elsevier BV
Published
2019-12
Volume
121
Pages
115420
ISSN
0165-9936 (ISSN-L)
DOI
10.1016/j.trac.2019.02.021
OpenAlex
W2916144014
Cited by
344
References
71
Citations by year
2026: 47 · 2025: 63 · 2024: 52 · 2023: 62 · 2022: 51 · 2021: 32 · 2020: 32 · 2019: 5
FWCI
13.05
Type
journal article
Language
en
Open access
Licence
Locations
TrAC Trends in Analytical Chemistry (publishedVersion, cc-by-nc-nd)
Funders
National Natural Science Foundation of China
Topics
  • Physical Sciences › Environmental Science › Environmental Chemistry › Per- and polyfluoroalkyl substances research
  • Life Sciences › Pharmacology, Toxicology and Pharmaceutics › Pharmaceutical Science › Fluorine in Organic Chemistry
  • Physical Sciences › Chemistry › Spectroscopy › Mass Spectrometry Techniques and Applications
Keywords
PFAS, high-resolution mass spectrometry, emerging PFASs, environmental contamination, human biofluids, commercial products, data processing strategies, organic fluorine, PFAS alternatives, source identification

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-06.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-06.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

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