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Cited by 399Per- and polyfluoroalkyl substances researchFluorine in Organic ChemistryAnalytical chemistry methods development

Worldwide trends in tracing poly- and perfluoroalkyl substances (PFAS) in the environment

Open access
Nakayama, Shoji F., Yoshikane, Mitsuha, Onoda, Yu, Nishihama, Yukiko, Iwai-Shimada, Miyuki, Takagi, Mai, Kobayashi, Yayoi, Isobe, Tomohiko·2019·TrAC Trends in Analytical Chemistry
DOI 10.1016/j.trac.2019.02.011
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Abstract

Numerous poly- and perfluoroalkyl substances (PFAS) have been manufactured and distributed on the world market. Research on PFAS has highlighted their global distribution and impacts on ecosystems and human health. Following regulations and public concern, PFAS production has shifted toward novel molecules in recent years. New classes of PFAS have been identified in the environment and are gaining worldwide attention. The development of an efficient strategy for identification and quantification of emerging PFAS is essential for risk assessment. This review presents and discusses the most recent analytical method development for PFAS in air, water, abiotic solid matrices and biological matrices, and addresses non-target approaches. Various methods are covered including sampling, pre-treatment (enrichment, extraction and clean-up) and instrumental analysis, and their applications, advantages, shortcomings and future needs are explored.

AI snapshot

Written from the paper’s full text.

TL;DR

This review synthesizes analytical methods for tracing PFAS across air, water, abiotic solids, and biological matrices, emphasizing the shift from legacy PFAS to novel alternatives. It finds that HRMS-based non-target and non-specific approaches are expanding discovery but remain limited by non-standardized methods, matrix effects, and a lack of reference standards.

Key findings

  • More than 4,000 PFAS are registered on the global market, and research has shifted toward novel PFAS; non-target analysis identified over 300 novel PFAS in 10 classes in pooled fish liver, while one study identified 47 new and 43 infrequently reported PFAS.
  • In air, GAPS 2009–2015 detected FTOHs at <0.4–21 pg/m³ in the polar region and 40–238 pg/m³ at urban sites; outdoor PFSA concentrations showed increasing trends (p < 0.001), and indoor FTOHs ranged from 246 to 62,100 pg/m³.
  • In water, PFOS and PFOA reached 0.13–881 ng/L and 1.28–24,700 ng/L, respectively, in Bohai Sea rivers and drain outlets; novel PFAS including HFPO-DA, HFPO-TA, and 6:2 Cl-PFESA were widely detected with median values of 0.95, 0.21, and 0.31 ng/L across countries.
  • Sediment PFOS and PFOA ranged from ND to 623 ng/g dw and ND to 16 ng/g dw; 6:2 Cl-PFESA in frog liver ranged from 0.13 to 119 ng/g ww, and human blood PFOS/PFOA decreased in the Northern hemisphere but increased in China near manufacturing sites.

Methods

  • Narrative review of recent analytical method development for PFAS in air, aqueous matrices, abiotic solid matrices, and wildlife/human biological samples, plus non-target and non-specific analyses.
  • Covers sampling, pre-treatment (enrichment, extraction, clean-up), instrumental analysis (GC-MS, HPLC-MS/MS, HRMS, etc.), and reported applications, advantages, shortcomings, and future needs.
  • No new experiments or primary data are reported; the synthesis draws on published studies and summary tables.

Limitations

  • The paper states that there is no standardised air sampling methodology, which hampers comparison of global studies, and that simultaneous analytical methods for anionic and neutral PFAS in air are scarce.
  • It states that non-target analysis remains in its infancy, with unstandardised sample pretreatment and data analysis, making it suitable for discovery rather than comprehensive quantitative analysis; non-specific methods cannot estimate toxicological effects and are not usable for regulatory purposes at present.
  • It reports that matrix effects/ion suppression, low recoveries for short-chain PFAS, and the lack of all isotope-labelled reference standards and representative matrices limit quantification; evident from the text, this is a narrative review without a systematic search strategy or quantitative meta-analysis.

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

Integrity signals

Registry

Crossref · 10.1016/j.trac.2019.02.011

Cites

101 of 101 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 142 cited sources checked · 0 supported · 0 flagged

  • Interpretationnone given

    Most methods reported to date have used extraction of filters to derive particulate fractions for calculating atmospheric PFCA concentrations.

    “Most methods reported to date have used extraction of filters to derive particulate fractions for calculating atmospheric PFCA concentrations.”
    Quote in the paperNot a substantial claim
  • Premisecitation

    Novel PFAS have been identified by suspected and non-targeted screening of airborne particles, water, sediments and biological samples.

    “Novel PFAS have been identified by suspected and non-targeted screening of airborne particles [16], water [17], sediments [17] and biological samples [18,19] (Table 1).”
    Quote in the paperNot a substantial claim0 of 4 sources checked
    • cites [16] Yu, 2018, Non-target and suspect screening of per- and polyfluoroalkyl substances in airborne particulate matter in China, Environ. Sci. Technol. source

      Not checked in the free run.

    • cites [17] Newton, 2017, Novel polyfluorinated compounds identified using high resolution mass spectrometry downstream of manufacturing facilities near Decatur, Alabama, Environ. Sci. Technol. source

      Not checked in the free run.

    • cites [18] 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 [19] Rotander, 2015, Novel fluorinated surfactants tentatively identified in firefighters using liquid chromatography quadrupole time-of-flight tandem mass spectrometry and a case-control approach, Environ. Sci. Technol. source

      Not checked in the free run.

  • Premisecitation

    Research on PFAS has shifted from original PFAS classes such as PFSAs and PFCAs toward new fluorinated compounds possessing one or more perfluoroalkyl moieties.

    “Over the last decade, research on poly-and perfluoroalkyl substances (PFAS) has shifted from original PFAS classes such as perfluoroalkyl sulphonic acids (PFSAs) and perfluoroalkyl carboxylic acids (PFCAs) toward new fluorinated compounds possessing one or more perfluoroalkyl (-C n F 2n -) moieties [1].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [1] Buck, 2011, Perfluoroalkyl and polyfluoroalkyl substances in the environment: terminology, classification, and origins, Integr. Environ. Assess. Manag. source

      Not checked in the free run.

  • Premisecitation

    PFAS levels in core sediment samples from the Great Lakes region of North America in 2006 and 2009 were higher in the top layers than the deeper layers.

    “PFAS levels were measured in core sediment samples collected from the Great Lakes region of North America in 2006 and 2009, and were also higher in the top layers [28] than the deeper layers [63].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [28] Tian, 2018, Occurrence and phase distribution of neutral and ionizable per- and polyfluoroalkyl substances (PFASs) in the atmosphere and plant leaves around landfills: a case study in Tianjin, China, Environ. Sci. Technol. source

      Not checked in the free run.

    • cites [63] Guo, 2016, Application of a comprehensive extraction technique for the determination of poly- and perfluoroalkyl substances (PFASs) in Great Lakes Region sediments, Chemosphere source

      Not checked in the free run.

  • Premisecitation

    Temporal studies and model predictions suggest that sediments, soils and sludges are an important environmental sink for PFAS.

    “Temporal studies and model predictions suggest that sediments, soils and sludges are an important environmental sink for PFAS [73].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [73] Su, 2018, Dynamic multimedia fate simulation of perfluorooctane sulfonate (PFOS) from 1981 to 2050 in the urbanizing Bohai Rim of China, Environ. Pollut. source

      Not checked in the free run.

  • May combine two claims. 29
  • Classified as probably not a substantial claim. 37
  • The quote only partly states this claim. 3

  • May combine two claims.

    Interpretationreasoning

    Recent research has focused on the identification of new PFAS and the development of methods that can detect, capture and characterise alternative molecules.

    “In accordance with the shift toward manufacturing alternatives, recent research has focused on the identification of new PFAS and the development of methods that can detect, capture and characterise these alternative molecules.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: PFAS production has shifted toward novel molecules in recent years following regulations and public concern.

  • May combine two claims.

    Premisecitation

    New classes of PFAS have been identified in the environment and are gaining worldwide attention.

    “New classes of PFAS have been identified in the environment and are gaining worldwide attention.”
    Quote in the paperSubstantial claim0 of 4 sources checked
    • cites [16] Yu, 2018, Non-target and suspect screening of per- and polyfluoroalkyl substances in airborne particulate matter in China, Environ. Sci. Technol. source

      Not checked in the free run.

    • cites [17] Newton, 2017, Novel polyfluorinated compounds identified using high resolution mass spectrometry downstream of manufacturing facilities near Decatur, Alabama, Environ. Sci. Technol. source

      Not checked in the free run.

    • cites [18] 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 [19] Rotander, 2015, Novel fluorinated surfactants tentatively identified in firefighters using liquid chromatography quadrupole time-of-flight tandem mass spectrometry and a case-control approach, Environ. Sci. Technol. source

      Not checked in the free run.

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

    Premisecitation

    Analytical methods covering novel PFAS were scarce.

    “Lorenzo et al. evaluated publications from 2011 to 2017 on the challenges of analysing emerging persistent organic pollutants in aquatic environments and concluded that analytical methods covering novel PFAS were scarce [9].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [9] Lorenzo, 2018, Analytical challenges to determine emerging persistent organic pollutants in aquatic ecosystems, Trends Anal. Chem. source

      Not checked in the free run.

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

    Premisecitation

    PFCAs may be adsorbed by the surface of filters, potentially causing overestimation of PFCA concentrations when using filter extraction.

    “Johansson et al. emphasised the potential for overestimation of PFCA concentrations using this method since PFCAs may be adsorbed by the surface of filters [33].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [33] Johansson, 2017, Can the use of deactivated glass fibre filters eliminate sorption artefacts associated with active air sampling of perfluorooctanoic acid?, Environ. Pollut. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationreasoning

    Passive samplers employing an SIP disk are widely used for global monitoring of outdoor air due to simplicity and cost-efficiency.

    “Due to simplicity and cost-efficiency, passive samplers employing an SIP disk are widely used for global monitoring of outdoor air.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationnone given

    Instrumental analysis of PFAS in aquatic matrices has not changed substantially in the past decade.

    “Instrumental analysis of PFAS in aquatic matrices has not changed substantially in the past decade.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationnone given

    Sampling and extraction methods for air samples are optimised for anionic and neutral compounds, even though novel PFAS are emerging in other matrices.

    “Sampling and extraction methods for air samples are optimised for anionic and neutral compounds, even though novel PFAS are emerging in other matrices.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationnone given

    SPE cartridges tend to be applied for indoor air monitoring.

    “By contrast, SPE cartridges tend to be applied for indoor air monitoring.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Most studies of PFAS in aquatic matrices used HPLC-MS/MS, although some used HRMS such as Orbitrap- or TOF-MS.

    “Most studies used HPLC-MS/MS [40e44, 46,47,50], although some studies used HRMS such as Orbitrap-or time-of-flight (TOF)-MS for quantitative and qualitative analyses [14,15].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [14] Concha-Graña, 2018, Fast and sensitive determination of per- and polyfluoroalkyl substances in seawater, J. Chromatogr. A source

      Not checked in the free run.

    • cites [15] Tröger, 2018, Micropollutants in drinking water from source to tap - method development and application of a multiresidue screening method, Sci. Total Environ. source

      Not checked in the free run.

  • May combine two claims.

    Interpretationcitation

    The most notable development for PFAS analysis in aqueous matrices during the last decade is the miniaturisation of extraction procedures such as DLLME, VALLME and micro-SPE, which has decreased the required sample volume and the amount of extraction solvent needed.

    “The most notable development for PFAS analysis in aqueous matrices during the last decade is the miniaturisation of extraction procedures such as DLLME, VALLE and micro-SPE, which has decreased the required sample volume and the amount of extraction solvent needed [14,15].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [14] Concha-Graña, 2018, Fast and sensitive determination of per- and polyfluoroalkyl substances in seawater, J. Chromatogr. A source

      Not checked in the free run.

    • cites [15] Tröger, 2018, Micropollutants in drinking water from source to tap - method development and application of a multiresidue screening method, Sci. Total Environ. source

      Not checked in the free run.

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

    Premisecitation

    A few publications report a direct injection approach for PFAS analysis, and various water samples have been analysed by DI-LC-MS/MS.

    “A few publications report a direct injection (DI) approach for PFAS analysis, and various water samples including drinking water, ground water, river water, lake water and wastewater have been analysed by DI-LC-MS/MS [41].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [41] Ciofi, 2018, Applicability of the direct injection liquid chromatographic tandem mass spectrometric analytical approach to the sub-ng L−1 determination of perfluoro-alkyl acids in waste, surface, ground and drinking water samples, Talanta source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Greater attention has been paid to contamination from sampling equipment during collection and storage of biological samples, since adsorption of target compounds to sample containers and equipment can be minimised by the matrix content.

    “For collection of biological samples, greater attention has been paid to contamination from sampling equipment during collection and storage, since the adsorption of target compounds to sample containers and equipment can be minimised by the matrix content [6].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [6] van Leeuwen, 2007, Extraction and clean-up strategies for the analysis of poly- and perfluoroalkyl substances in environmental and human matrices, J. Chromatogr. A source

      Not checked in the free run.

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

    Premisecitation

    A VALLME method achieved an LOD of 1.6 ng/L for PFOS in tap, river and well water samples.

    “In another report, a VALLME method achieved a limit of detection (LOD) of 1.6 ng/L for PFOS in tap, river and well water samples [48].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [48] Papadopoulou, 2011, Fast screening of perfluorooctane sulfonate in water using vortex-assisted liquid-liquid microextraction coupled to liquid chromatography-mass spectrometry, Anal. Chim. Acta source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    DLLME methods utilise less extraction solvent and thereby decrease environmental burden, achieving sufficient recoveries (80.6%-121% for tap water, river water and urine) and relatively low detection limits (0.6-8.7 ng/L for water and urine).

    “Green chemistry methods using DLLME were recently developed [9,38] that utilise less extraction solvent and thereby decrease the environmental burden, achieving sufficient recoveries (80.6%e121% for tap water, river water and urine samples) and relatively low detection limits (0.6e8.7 ng/L for water and urine samples).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [9] Lorenzo, 2018, Analytical challenges to determine emerging persistent organic pollutants in aquatic ecosystems, Trends Anal. Chem. source

      Not checked in the free run.

    • cites [38] 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.

  • The quote only partly states this claim.

    Interpretationnone given

    Few remarkable developments in pre-treatment procedures for abiotic solid matrices have occurred in the last decade.

    “Few remarkable developments in pre-treatment procedures have occurred in the last decade.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Marine sediment core samples collected in China and Korea displayed similar trends, with higher levels of PFAS detected in surface layers.

    “Marine sediment core samples collected in China and Korea displayed similar trends, with higher levels of PFAS detected in surface layers [64].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [64] Shen, 2018, Historical trends of perfluoroalkyl substances (PFASs) in dated sediments from semi-enclosed bays of Korea, Mar. Pollut. Bull. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Recent PFAS research in abiotic solid matrices has focused on identifying and quantifying PFAS in soil, evaluating adsorption of PFAS to solid matrices, and optimising extraction methods for novel PFAS.

    “Recent PFAS research in this field has focused on identifying and quantifying PFAS in soil matrices [55,56], evaluating the adsorption of PFAS to solid matrices [57e59] and optimising extraction methods for novel PFAS [60].”
    Quote in the paperNot a substantial claim0 of 4 sources checked
    • cites [55] Skaar, 2018, Elucidation of contamination sources for poly- and perfluoroalkyl substances (PFASs) on Svalbard (Norwegian Arctic), Environ. Sci. Pollut. Res.

      Not checked in the free run.

    • cites [56] Anderson, 2016, Occurrence of select perfluoroalkyl substances at U.S. Air Force aqueous film-forming foam release sites other than fire-training areas: field-validation of critical fate and transport properties, Chemosphere source

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    • cites [57e59]

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    • cites [60] Munoz, 2018, Optimization of extraction methods for comprehensive profiling of perfluoroalkyl and polyfluoroalkyl substances in firefighting foam impacted soils, Anal. Chim. Acta source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    VALLME employs a vortex mixer instead of dispersive solvent, making it simpler than DLLME, and was applied to PFAS analysis in seawater with a method quantitation limit <7 ng/L.

    “Vortex-assisted liquidliquid microextraction (VALLME) employs a vortex mixer instead of dispersive solvent, which is much simpler than the two different solvent systems employed in DLLME methods.This technique was applied for PFAS analysis (PFOS, PFOA and FASAs) in seawater, resulting in a method quantitation limit <7 ng/L with a sample volume of 35 mL and 0.85 mL of solvent using an LTQ-Orbitrap”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [14] Concha-Graña, 2018, Fast and sensitive determination of per- and polyfluoroalkyl substances in seawater, J. Chromatogr. A source

      Not checked in the free run.

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

    Premisecitation

    SBSE has been developed as an environmentally friendly technique and applied to PFAS research.

    “Stir bar sorptive extraction (SBSE) has been developed as an environmentally friendly technique and applied to PFAS research [49].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [49] Martín, 2016, Polar stir bars for isolation and preconcentration of perfluoroalkyl substances from human milk samples prior to UHPLC-MS/MS analysis, Bioanalysis source

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  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationnone given

    GC-MS is the predominant method for volatile PFAS analysis in solids.

    “GC-MS is the predominant method for volatile PFAS analysis in solids.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given

    HPLC-MS/MS is mainly used for biological sample analysis.

    “HPLC-MS/MS is mainly used for biological sample analysis.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationnone given

    The sample volume required for PFAS analysis in blood has decreased during the last decade from millilitres to tens of microlitres.

    “The sample volume required for PFAS analysis in blood has decreased during the last decade from millilitres to tens of microlitres.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    HFPO-DA, HFPO-TA and 6:2 Cl-PFESA were widely detected in all countries including China, the United States, the United Kingdom, Sweden, Germany, the Netherlands and South Korea, with median values of 0.95, 0.21 and 0.31 ng/L, respectively.

    “Hexafluoropropylene oxide dimer acid (HFPO-DA), hexafluoropropylene oxide trimer acid (HFPO-TA) and 6:2 Cl-PFESA were widely detected in all countries including China (n ¼ 106), the United States (n ¼ 12), the United Kingdom (n ¼ 6), Sweden (n ¼ 10), Germany (n ¼ 14), the Netherlands (n ¼ 6) and South Korea (n ¼ 6), with median values of 0.95, 0.21 and 0.31 ng/L, respectively.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [54] Pan, 2018, Worldwide distribution of novel perfluoroether carboxylic and sulfonic acids in surface water, Environ. Sci. Technol. source

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

    Premisecitation

    Various extraction methods such as SLE, LLE, IPE, alkaline digestion and acetonitrile protein precipitation have been investigated for clean-up of multiple coexisting matrices.

    “Various extraction methods such as SLE, LLE, IPE, alkaline digestion and acetonitrile protein precipitation have been investigated for clean-up of multiple coexisting matrices [79,80,85,87].”
    Quote in the paperNot a substantial claim0 of 4 sources checked
    • cites [79] Wang, 2018, Using hair, nail and urine samples for human exposure assessment of legacy and emerging per- and polyfluoroalkyl substances, Sci. Total Environ. source

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    • cites [80] Cui, 2018, Occurrence and tissue distribution of novel perfluoroether carboxylic and sulfonic acids and legacy per/polyfluoroalkyl substances in black-spotted frog (Pelophylax nigromaculatus), Environ. Sci. Technol. source

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    • cites [85] Li, 2013, Can nail, hair and urine be used for biomonitoring of human exposure to perfluorooctane sulfonate and perfluorooctanoic acid?, Environ. Int. source

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    • cites [87] Gao, 2018, Simultaneous determination of 21 trace perfluoroalkyl substances in fish by isotope dilution ultrahigh performance liquid chromatography tandem mass spectrometry, J. Chromatogr. B Anal. Technol. Biomed. Life Sci. source

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

    Premisecitation

    To obtain data representative of human and wildlife populations, high-throughput techniques such as online SPE or dualcolumn systems coupled with HPLC-MS/MS are often employed.

    “To obtain data that are representative of human and wildlife populations, high-throughput techniques such as online SPE or dualcolumn systems coupled with HPLC-MS/MS are often employed [84,88].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [84] Gao, 2018, An integrated method for simultaneously determining 10 classes of per- and polyfluoroalkyl substances in one drop of human serum, Anal. Chim. Acta source

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    • cites [88] Huber, 2015, An automated high-throughput SPE micro-elution method for perfluoroalkyl substances in human serum, Anal. Bioanal. Chem. source

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

    Premisecitation

    Yao et al. prepared stir bars coated with adsorbent material and achieved sufficient recoveries for diverse PFAS including PFCAs (C4-C12) and PFSAs (C6 and C8).

    “Yao et al. prepared stir bars coated with adsorbent material and achieved sufficient recoveries for diverse PFAS including PFCAs (C4eC12) and PFSAs (C6 and C8) [50].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [50] Yao, 2018, One-pot polymerization of monolith coated stir bar for high efficient sorptive extraction of perfluoroalkyl acids from environmental water samples followed by high performance liquid chromatography-electrospray tandem mass spectrometry detection, J. Chromatogr. A source

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

    Premisecitation

    Oasis WAX and Strata X-AW are also used for aqueous sample analysis.

    “Oasis WAX (Waters, Inc.) and Strata X-AW (Phenomenex) are also used for aqueous sample analysis [40,43,44].”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [40] Dalahmeh, 2018, Per- and polyfluoroalkyl substances (PFASs) in water, soil and plants in wetlands and agricultural areas in Kampala, Uganda, Sci. Total Environ. source

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    • cites [43] Wei, 2018, Distribution, source identification and health risk assessment of PFASs and two PFOS alternatives in groundwater from non-industrial areas, Ecotoxicol. Environ. Saf. source

      Not checked in the free run.

    • cites [44] Janda, 2018, Robust trace analysis of polar (C2-C8) perfluorinated carboxylic acids by liquid chromatography-tandem mass spectrometry: method development and application to surface water, groundwater and drinking water, Environ. Sci. Pollut. Res.

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    In the survey at Alert, Canada (2006-2014), FTOHs, FASAs and FASEs were detected at concentrations <0.17-30 pg/m3, <0.014-0.82 pg/m3 and <0.10-4.8 pg/m3, respectively, similar to concentrations measured in the GAPS survey.

    “In the survey conducted at Alert, Canada (2006e2014), FTOHs, FASAs and FASEs were detected at concentrations < 0.17e30 pg/m 3 , <0.014e0.82pg/m 3 and <0.10e4.8pg/m 3 , respectively, similar to concentrations measured in the GAPS survey [21,26].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [21] Wong, 2018, Assessing temporal trends and source regions of per- and polyfluoroalkyl substances (PFASs) in air under the Arctic Monitoring and Assessment Programme (AMAP), Atmos, Environ. Times

      Not checked in the free run.

    • cites [26] Rauert, 2018, Atmospheric concentrations and trends of poly- and perfluoroalkyl substances (PFAS) and volatile methyl siloxanes (VMS) over 7 years of sampling in the Global Atmospheric Passive Sampling (GAPS) network, Environ. Pollut. source

      Not checked in the free run.

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

    Premisecitation

    Oasis HLB series or Strata-X cartridges tend to be employed for analysis of diverse target compounds.

    “Oasis HLB series or Strata-X cartridges (Phenomenex, Torrance, CA, USA) tend to be employed for analysis of diverse target compounds [7,9,15,42,45].”
    Quote in the paperNot a substantial claim0 of 5 sources checked
    • cites [7] Jahnke, 2009, Trace analysis of per- and polyfluorinated alkyl substances in various matrices-How do current methods perform?, J. Chromatogr. A source

      Not checked in the free run.

    • cites [9] Lorenzo, 2018, Analytical challenges to determine emerging persistent organic pollutants in aquatic ecosystems, Trends Anal. Chem. source

      Not checked in the free run.

    • cites [15] Tröger, 2018, Micropollutants in drinking water from source to tap - method development and application of a multiresidue screening method, Sci. Total Environ. source

      Not checked in the free run.

    • cites [42] Gallen, 2018, A mass estimate of perfluoroalkyl substance (PFAS) release from Australian wastewater treatment plants, Chemosphere source

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    • cites [45] Ayala-Cabrera, 2018, Negative-ion atmospheric pressure ionisation of semi-volatile fluorinated compounds for ultra-high-performance liquid chromatography tandem mass spectrometry analysis, 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

    Janda et al. developed an analytical method for short-chain PFCAs such as TFA and PFPrA in surface water, ground water and drinking water using Oasis WAX, resulting in sufficient PFAS recoveries at pH 3-4.

    “Janda et al. developed an analytical method for short-chain PFCAs such as trifluoroacetic acid (TFA) and perfluoropropanoic acid (PFPrA) in surface water, ground water and drinking water samples using Oasis WAX, resulting in sufficient PFAS recoveries at pH 3e4 [44].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [44] Janda, 2018, Robust trace analysis of polar (C2-C8) perfluorinated carboxylic acids by liquid chromatography-tandem mass spectrometry: method development and application to surface water, groundwater and drinking water, Environ. Sci. Pollut. Res.

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationnone given

    A recent trend for biological samples, especially for human biomonitoring, is the simplification of pre-treatment steps and employment of high-throughput analysis, including online SPE techniques.

    “A recent trend for biological samples, especially for human biomonitoring, is the simplification of pre-treatment steps and employment of high-throughput analysis, including online SPE techniques.”
    Quote in the paperNot a substantial claim

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

    Premisecitation

    A polymer-based SPE cartridge is commonly employed for PFAS analysis.

    “A polymer-based SPE cartridge is commonly employed for PFAS analysis [6,7,9].”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [6] van Leeuwen, 2007, Extraction and clean-up strategies for the analysis of poly- and perfluoroalkyl substances in environmental and human matrices, J. Chromatogr. A source

      Not checked in the free run.

    • cites [7] Jahnke, 2009, Trace analysis of per- and polyfluorinated alkyl substances in various matrices-How do current methods perform?, J. Chromatogr. A source

      Not checked in the free run.

    • cites [9] Lorenzo, 2018, Analytical challenges to determine emerging persistent organic pollutants in aquatic ecosystems, Trends Anal. Chem. source

      Not checked in the free run.

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

    Premisenone given

    For ionic PFAS in solids, instruments are similar to those used for aqueous matrices by HPLC-negative ESI-MS/MS.

    “For ionic PFAS, instruments are similar to those used for analysis of aqueous matrices by HPLC-negative ESI-MS/MS.”
    Quote in the paperNot a substantial claim

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

    Premisecitation

    An SPE cartridge filled with bamboo charcoal was developed for determination of trace PFAS in environmental water samples.

    “An SPE cartridge filled with bamboo charcoal, a new biomaterial with microporous characteristics, was developed for determination of trace PFAS in environmental water samples [46].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [46] Deng, 2018, Preconcentration and determination of perfluoroalkyl substances (PFASs) in water samples by bamboo charcoal-based solid-phase extraction prior to liquid chromatography–tandem mass spectrometry, Molecules source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given

    LC conditions for solids are generally similar to those adopted for air and aqueous matrices.

    “LC conditions are generally similar to those adopted for air and aqueous matrices.”
    Quote in the paperNot a substantial claim

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

    Premisecitation

    Zhang et al. reported that an alkyl perfluorinated C8 column achieved better separation characteristics for PFAS isomers than a C18 column.

    “Zhang et al. reported that an alkyl perfluorinated C8 column (Epic FO LB, ES Industries, Inc., West Berlin, NJ, USA) achieved better separation characteristics for PFAS isomers than a C18 column [69].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [69] Zhang, 2018, Determination of perfluoroalkyl acid isomers in biosolids, biosolids-amended soils and plants using ultra-high performance liquid chromatography tandem mass spectrometry, J. Chromatogr. B Anal. Technol. Biomed. Life Sci. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    PFSA concentrations in outdoor air displayed increasing trends (p<0.001), but there were no such trends for FTOHs, FASAs, FASEs and PFCAs from 2009 to 2015.

    “PFSA concentrations in outdoor air displayed increasing trends (p < 0.001), but there were no such trends for FTOHs, FASAs, FASEs and PFCAs from 2009 to 2015 [26].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [26] Rauert, 2018, Atmospheric concentrations and trends of poly- and perfluoroalkyl substances (PFAS) and volatile methyl siloxanes (VMS) over 7 years of sampling in the Global Atmospheric Passive Sampling (GAPS) network, Environ. Pollut. source

      Not checked in the free run.

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

    Premisecitation

    To increase recovery of short-chain PFCAs (C2-C4), Tian et al. suggested use of an ion-exchange column for HPLC separation.

    “To increase the recovery of short-chain PFCAs (C2eC4), Tian et al. suggested the use of an ionexchange column (Shodex RSpak JJ-50 2D; Showa Denko America, Inc., New York, NY, USA) for HPLC separation [28].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [28] Tian, 2018, Occurrence and phase distribution of neutral and ionizable per- and polyfluoroalkyl substances (PFASs) in the atmosphere and plant leaves around landfills: a case study in Tianjin, China, Environ. Sci. Technol. source

      Not checked in the free run.

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

    Premisecitation

    For neutral PFAS such as FASAs, FASEs and FTOHs, APCI and APPI have also been tested.

    “For neutral PFAS such as FASAs, FASEs and FTOHs, atmospheric pressure chemical ionisation (APCI) and atmospheric pressure photoionisation (APPI) have also been tested [45].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [45] Ayala-Cabrera, 2018, Negative-ion atmospheric pressure ionisation of semi-volatile fluorinated compounds for ultra-high-performance liquid chromatography tandem mass spectrometry analysis, Anal. Bioanal. Chem. source

      Not checked in the free run.

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

    Premisecitation

    Simultaneous analyses of PFAS, pharmaceuticals, personal care products and pesticides were developed using polymer-based SPE cartridges.

    “Simultaneous analyses of PFAS, pharmaceuticals, personal care products and pesticides were developed using these types of SPE cartridges [15].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [15] Tröger, 2018, Micropollutants in drinking water from source to tap - method development and application of a multiresidue screening method, Sci. Total Environ. source

      Not checked in the free run.

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

    Premisecitation

    A few studies used Orbitrap-MS or TOF-MS for PFAS in solids.

    “A few studies used Orbitrap-MS [68] or TOF-MS [17].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [68] Ruan, 2015, Identification of novel polyfluorinated ether sulfonates as PFOS alternatives in municipal sewage sludge in China, Environ. Sci. Technol. source

      Not checked in the free run.

    • cites [17] Newton, 2017, Novel polyfluorinated compounds identified using high resolution mass spectrometry downstream of manufacturing facilities near Decatur, Alabama, Environ. Sci. Technol. source

      Not checked in the free run.

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

    Premisenone given

    LLE is frequently applied as a clean-up method for PFAS analysis.

    “LLE is yet another technique frequently applied as a clean-up method for PFAS analysis.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Levels of ionic PFAS differed between study sites; PFCAs and PFSAs ranged from 90.9 to 1,970 pg/m3 and 86.8-587 pg/m3, respectively, and were higher in houses, while total FASA/FASE levels were higher in hotels and ranged from ND to 2,460 pg/m3.

    “Levels of ionic PFAS differed between study sites; PFCAs and PFSAs ranged from 90.9 to 1,970 pg/m 3 and 86.8e587 pg/m 3 , respectively, and were higher in houses, while total FASA/FASE levels were higher in hotels and ranged from nondetectable (ND) to 2,460 pg/m 3 [22].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [22] Yao, 2018, Per- and polyfluoroalkyl substances (PFASs) in indoor air and dust from homes and various microenvironments in China: implications for human exposure, Environ. Sci. Technol. source

      Not checked in the free run.

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

    Premisereasoning

    Since most target PFAS are anionic, MS is generally operated in ESI-negative mode.

    “Since most target PFAS are anionic, MS is generally operated in ESI-negative mode.”
    Quote in the paperNot a substantial claim

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

    Premisecitation

    Wang et al. concluded that solvent extraction achieves better recoveries than SPE (WAX, HLB and C18) with filtration as a pre-treatment method.

    “Wang et al. compared SPE (WAX, HLB and C18) with solvent extraction and filtration as a pre-treatment method and concluded that solvent extraction achieves better recoveries [61].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [61] Wang, 2018, Optimization of sample preparation and chromatography for the determination of perfluoroalkyl acids in sediments from the Yangtze Estuary and East China Sea, Chemosphere source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Short-chain PFCAs (C2-C8) were detected in the range of 0.056 μg/L (PFPrA) to 2.2 μg/L (TFA) from ground water (n=5) collected at polluted sites in Baden-Wurttemberg, Germany, with TFA and PFOA the predominant analytes.

    “Short-chain PFCAs (C2eC8) were detected in the range of 0.056 mg/ L (PFPrA) to 2.2 mg/L (TFA) from ground water (n ¼ 5) collected at polluted sites in the state of Baden-Wurttemberg, Germany, with TFA and PFOA the predominant analytes [44].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [44] Janda, 2018, Robust trace analysis of polar (C2-C8) perfluorinated carboxylic acids by liquid chromatography-tandem mass spectrometry: method development and application to surface water, groundwater and drinking water, Environ. Sci. Pollut. Res.

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    A systematic review of temporal trends reported a decrease in blood PFOS and PFOA levels in human samples from the Northern hemisphere, despite environmental media showing no clear decreasing trend.

    “A systematic review of temporal trends reported a decrease in blood PFOS and PFOA levels in human samples from the Northern hemisphere, despite the fact that environmental media have shown no such clear decreasing trend [11].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [11] Land, 2018, What is the effect of phasing out long-chain per- and polyfluoroalkyl substances on the concentrations of perfluoroalkyl acids and their precursors in the environment? A systematic review, Environ. Evid. source

      Not checked in the free run.

  • The quote only partly states this claim.

    Premisecitation

    6:2 and 8:2 Cl-PFESA and PFOS have bioaccumulated and been biomagnified in the marine ecosystem near the Bohai Sea, China.

    “revealing that 6:2 and 8:2 Cl-PFESA and PFOS have bioaccumulated and been biomagnified in the marine ecosystem.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [78] Chen, 2018, Distribution, bioaccumulation and trophic transfer of chlorinated polyfluoroalkyl ether sulfonic acids in the marine food web of Bohai, China, Environ. Pollut. source

      Not checked in the free run.

  • The quote only partly states this claim.

    Premisecitation

    6:2 Cl-PFESA was detected in 88%-95% of urine, hair and nail samples evaluated in two populations with different exposure conditions.

    “6:2 Cl-PFESA was detected in 88%e95% of samples.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [79] Wang, 2018, Using hair, nail and urine samples for human exposure assessment of legacy and emerging per- and polyfluoroalkyl substances, Sci. Total Environ. source

      Not checked in the free run.

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

    Premisecitation

    Nail is an ideal matrix for PFOS biomonitoring.

    “concluded that nail was an ideal matrix for PFOS biomonitoring [89].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [89] Wang, 2018, Occurrence of perfluoroalkyl substances in matched human serum, urine, hair and nail, J. Environ. Sci. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Most (~90%) studies published in the past two decades measured PFAS in blood samples, while a few employed breast milk, urine, hair and nail samples.

    “most (~90%) studies published in the past two decades measured PFAS in blood samples, while a few studies employed breast milk, urine, hair and nail samples [12].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [12] Jian, 2018, A short review on human exposure to and tissue distribution of per- and polyfluoroalkyl substances (PFASs), Sci. Total Environ. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Removal of lipid components by sample freezing after SPE clean-up, graphite carbon clean-up, and addition of 1-methyl piperazine to the LC-MS/MS mobile phase have been suggested to overcome matrix problems, but none are perfect solutions.

    “Removal of lipid components by sample freezing after SPE clean-up [87], graphite carbon (e.g., ENVI-Carb) clean-up [83] and addition of 1-methyl piperazine to the LC-MS/MS mobile phase [83,84] have been suggested to overcome these problems, but none are perfect solutions.”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [87] Gao, 2018, Simultaneous determination of 21 trace perfluoroalkyl substances in fish by isotope dilution ultrahigh performance liquid chromatography tandem mass spectrometry, J. Chromatogr. B Anal. Technol. Biomed. Life Sci. source

      Not checked in the free run.

    • cites [83] Zabaleta, 2015, Simultaneous determination of perfluorinated compounds and their potential precursors in mussel tissue and fish muscle tissue and liver samples by liquid chromatography-electrospray-tandem mass spectrometry, J. Chromatogr. A source

      Not checked in the free run.

    • cites [84] Gao, 2018, An integrated method for simultaneously determining 10 classes of per- and polyfluoroalkyl substances in one drop of human serum, Anal. Chim. Acta source

      Not checked in the free run.

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

    Premisecitation

    The extractable organic fluorine (EOF) assay using CIC has been used for analysis of water, sediment and biological samples since first reported by Miyake et al., in 2007.

    “One of the most common non-specific methods is the extractable organic fluorine (EOF) assay using CIC that has been used for the analysis of water, sediment and biological samples since it was first reported by Miyake et al., in 2007 [97].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [97] 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. Chromatogr. A source

      Not checked in the free run.

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

    Premisecitation

    In-source fragmentation flagging scans for anionic PFAS have proved effective in some recent studies.

    “In-source fragmentation flagging scans for anionic PFAS have proved effective in some recent studies [18].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [18] 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

    PFPiAs were detected in all fish, birds and dolphins collected between 2004 and 2011 in various regions of North America at levels 1-2 orders of magnitude lower than PFCAs and PFSAs.

    “PFPiAs were detected in all animals at levels 1e2 orders of magnitude lower than those of PFCAs and PFSAs”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [82] De Silva, 2016, Perfluoroalkylphosphinic acids in northern pike (Esox lucius), double-crested cormorants (Phalacrocorax auritus), and bottlenose dolphins (Tursiops truncatus) in relation to other perfluoroalkyl acids, Environ. Sci. Technol. source

      Not checked in the free run.

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

    Premisecitation

    The EOF assay using CIC was most recently applied to detect PFAS in cosmetics.

    “Most recently, the technique was applied to detect PFAS in cosmetics [98].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [98] Schultes, 2018, Per- and polyfluoroalkyl substances and fluorine mass balance in cosmetic products from the Swedish market: implications for environmental emissions and human exposure, Environ. Sci. Process Impact. source

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    Sample pretreatment methods and data analysis procedures are not yet standardised; hence non-target approach can be used for discovery rather than comprehensive analysis of PFAS at present.

    “Sample pretreatment methods and data analysis procedures are not yet standardised; hence this approach can be used for discovery rather than comprehensive analysis of PFAS at present.”
    Quote in the paperSubstantial claim

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

    Premisecitation

    The TOP assay was most recently applied to groundwater samples to evaluate seepage of PFAS through soil of a firefighter training site to assess groundwater contamination.

    “Most recently, the TOP assay was applied to groundwater samples to evaluate seepage of PFAS through the soil of a firefighter training site to assess groundwater contamination [100].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [100] Dauchy, 2019, Deep seepage of per- and polyfluoroalkyl substances through the soil of a firefighter training site and subsequent groundwater contamination, Chemosphere source

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    The TOP assay has advantages over CIC since it does not require any specific instruments other than a simple LC-MS/MS system, and it can target precursors of specific PFAAs.

    “This method has advantages over CIC since it does not require any specific instruments other than a simple LC-MS/MS system, and it can target precursors of specific PFAAs.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

    Interpretationnone given

    PIGE spectroscopy and 19F NMR spectroscopy are promising non-destructive and non-specific methods, but few publications utilising these approaches have been reported to date.

    “PIGE spectroscopy and 19F NMR spectroscopy are promising non-destructive and non-specific methods, but few publications utilising these approaches have been reported to date.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    The TOP assay originally developed by Houtz and Sedlak achieved greater detection selectivity but only for substances that can be oxidised to specific PFAAs by comparing samples before and after oxidation by hydroxyl radicals.

    “The TOP assay originally developed by Houtz and Sedlak achieved greater detection selectivity but only for substances that can be oxidised to specific perfluoroalkyl acids (PFAAs) by comparing samples before and after oxidation by hydroxyl radicals [99].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [99] Houtz, 2012, Oxidative conversion as a means of detecting precursors to perfluoroalkyl acids in urban runoff, Environ. Sci. Technol. source

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    A vital shortcoming of non-specific methods is that their results cannot be used for estimating toxicological effects, preventing them from being used for regulatory purposes at present.

    “A vital shortcoming of non-specific methods is that their results cannot be used for estimating toxicological effects, preventing them from being used for regulatory purposes at present.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    Non-target approaches have identified many novel PFAS, but the technology remains in its infancy.

    “Promisingly, these non-target approaches have identified many novel PFAS, but the technology remains in its infancy.”
    Quote in the paperSubstantial claim

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

    Interpretationnone given

    The authors did not directly compare EOF and AOF assays using the same samples to evaluate differences between the two methods.

    “but the authors did not directly compare EOF and AOF assays using the same samples to evaluate differences between the two methods.”
    Quote in the paperNot a substantial claim
64 of 64

  • The paper relies on this without support.

    PFAS production has shifted toward novel molecules in recent years following regulations and public concern.

    “Following regulations and public concern, PFAS production has shifted toward novel molecules in recent years.”

  • The paper relies on this without support.

    There is no standardised methodology for monitoring PFAS in air.

    “There is no standardised methodology, which hampers comparison of global studies.”

  • The paper relies on this without support.

    Simultaneous analytical methods for anionic and neutral PFAS in air samples are scarce.

    “Furthermore, simultaneous analytical methods for anionic and neutral PFAS in air samples are scarce.”

  • The paper relies on this without support.

    Short-chain PFAS (C6 or shorter) have been increasingly manufactured and used worldwide as alternatives for long-chain PFAS.

    “Short-chain PFAS (C6 or shorter) have been increasingly manufactured and used worldwide as alternatives for longchain PFAS.”

  • The paper relies on this without support.

    Dust is one of the most important routes of human exposure to PFAS.

    “Dust is one of the most important routes of human exposure; hence a method suitable for both volatile and non-volatile PFAS is warranted.”

  • The paper relies on this without support.

    PFAS manufacturing has moved from Western to Asian countries.

    “As PFAS manufacturing has moved from Western to Asian countries, an increasing number of studies have been conducted in Asia.”

  • The paper relies on this without support.

    The main challenge when monitoring PFAS in air is sampling issues.

    “The main challenge when monitoring PFAS in air is sampling issues.”

  • The paper relies on this without support.

    Dust analysis methods have not been thoroughly explored.

    “Regarding dust analysis, one comprehensive review has covered survey sites, concentrations and daily intake of semi-volatile organic compounds (SVOC) including PFAS [13], but dust analysis methods have not been thoroughly explored.”

  • The paper relies on this without support.

    Most fluoropolymer production is now carried out in Asian countries.

    “Especially in Asian countries where most fluoropolymer production is now carried out”

  • The paper relies on this without support.

    Not all isotope-labelled reference standards are currently available, and matrices representative of all samples are also not available.

    “not all isotopelabelled reference standards are currently available, and matrices representative of all samples are also not available.”
10 of 10

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Authors
Nakayama, S. F., Yoshikane, M., Onoda, Y., Nishihama, Y., Iwai-Shimada, M., Takagi, M., Kobayashi, Y., & Isobe, T.
Affiliations
  • National Institute for Environmental Studies (JP)
  • IDEA Consultants, Inc. (Japan) (JP)
Corresponding author
Nakayama, Shoji F.
ORCID
Venue
TrAC Trends in Analytical Chemistry
Publisher
Elsevier BV
Published
2019-12
Volume
121
Pages
115410
ISSN
0165-9936 (ISSN-L)
DOI
10.1016/j.trac.2019.02.011
OpenAlex
W2911960135
Cited by
399
References
104
Citations by year
2026: 41 · 2025: 73 · 2024: 51 · 2023: 62 · 2022: 58 · 2021: 65 · 2020: 45 · 2019: 4
FWCI
18.73
Type
journal article
Language
en
Open access
Licence
Locations
TrAC Trends in Analytical Chemistry (publishedVersion, cc-by-nc-nd)
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 › Analytical Chemistry › Analytical chemistry methods development
Keywords
per- and polyfluoroalkyl substances, PFAS, emerging PFAS, environmental contamination, non-targeted analysis, sample preparation, sample enrichment, air analysis, water analysis, solid matrices, biological matrices, risk assessment

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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 2026-10-07.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-07.

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