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

In the paper

“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.”

In the paper

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

What the sources say

• Not checked yetcites [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 yetcites [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 yetcites [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 yetcites [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

In the paper

“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].”

What the sources say

• Not checked yetcites [9] Lorenzo, 2018, Analytical challenges to determine emerging persistent organic pollutants in aquatic ecosystems, Trends Anal. Chem. source

In the paper

“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].”

What the sources say

• Not checked yetcites [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

In the paper

“Due to simplicity and cost-efficiency, passive samplers employing an SIP disk are widely used for global monitoring of outdoor air.”

In the paper

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

In the paper

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

In the paper

“By contrast, SPE cartridges tend to be applied for indoor air monitoring.”

In the paper

“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].”

What the sources say

• Not checked yetcites [14] Concha-Graña, 2018, Fast and sensitive determination of per- and polyfluoroalkyl substances in seawater, J. Chromatogr. A source
• Not checked yetcites [15] Tröger, 2018, Micropollutants in drinking water from source to tap - method development and application of a multiresidue screening method, Sci. Total Environ. source

In the paper

“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].”

What the sources say

• Not checked yetcites [14] Concha-Graña, 2018, Fast and sensitive determination of per- and polyfluoroalkyl substances in seawater, J. Chromatogr. A source
• Not checked yetcites [15] Tröger, 2018, Micropollutants in drinking water from source to tap - method development and application of a multiresidue screening method, Sci. Total Environ. source

In the paper

“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].”

What the sources say

• Not checked yetcites [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

In the paper

“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].”

What the sources say

• Not checked yetcites [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

In the paper

“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].”

What the sources say

• Not checked yetcites [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

In the paper

“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).”

What the sources say

• Not checked yetcites [9] Lorenzo, 2018, Analytical challenges to determine emerging persistent organic pollutants in aquatic ecosystems, Trends Anal. Chem. source
• Not checked yetcites [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

In the paper

“Few remarkable developments in pre-treatment procedures have occurred in the last decade.”

In the paper

“Marine sediment core samples collected in China and Korea displayed similar trends, with higher levels of PFAS detected in surface layers [64].”

What the sources say

• Not checked yetcites [64] Shen, 2018, Historical trends of perfluoroalkyl substances (PFASs) in dated sediments from semi-enclosed bays of Korea, Mar. Pollut. Bull. source

In the paper

“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].”

What the sources say

• Not checked yetcites [55] Skaar, 2018, Elucidation of contamination sources for poly- and perfluoroalkyl substances (PFASs) on Svalbard (Norwegian Arctic), Environ. Sci. Pollut. Res.
• Not checked yetcites [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
• Not checked yetcites [57e59]
• Not checked yetcites [60] Munoz, 2018, Optimization of extraction methods for comprehensive profiling of perfluoroalkyl and polyfluoroalkyl substances in firefighting foam impacted soils, Anal. Chim. Acta source

In the paper

“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”

What the sources say

• Not checked yetcites [14] Concha-Graña, 2018, Fast and sensitive determination of per- and polyfluoroalkyl substances in seawater, J. Chromatogr. A source

In the paper

“Stir bar sorptive extraction (SBSE) has been developed as an environmentally friendly technique and applied to PFAS research [49].”

What the sources say

• Not checked yetcites [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

In the paper

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

In the paper

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

In the paper

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

In the paper

“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.”

What the sources say

• Not checked yetcites [54] Pan, 2018, Worldwide distribution of novel perfluoroether carboxylic and sulfonic acids in surface water, Environ. Sci. Technol. source

In the paper

“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].”

What the sources say

• Not checked yetcites [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 yetcites [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
• Not checked yetcites [85] Li, 2013, Can nail, hair and urine be used for biomonitoring of human exposure to perfluorooctane sulfonate and perfluorooctanoic acid?, Environ. Int. source
• Not checked yetcites [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

In the paper

“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].”

What the sources say

• Not checked yetcites [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 yetcites [88] Huber, 2015, An automated high-throughput SPE micro-elution method for perfluoroalkyl substances in human serum, Anal. Bioanal. Chem. source

In the paper

“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].”

What the sources say

• Not checked yetcites [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

In the paper

“Oasis WAX (Waters, Inc.) and Strata X-AW (Phenomenex) are also used for aqueous sample analysis [40,43,44].”

What the sources say

• Not checked yetcites [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
• Not checked yetcites [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 yetcites [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.

In the paper

“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].”

What the sources say

• Not checked yetcites [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 yetcites [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

In the paper

“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].”

What the sources say

• Not checked yetcites [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 yetcites [9] Lorenzo, 2018, Analytical challenges to determine emerging persistent organic pollutants in aquatic ecosystems, Trends Anal. Chem. source
• Not checked yetcites [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 yetcites [42] Gallen, 2018, A mass estimate of perfluoroalkyl substance (PFAS) release from Australian wastewater treatment plants, Chemosphere source
• Not checked yetcites [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

In the paper

“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].”

What the sources say

• Not checked yetcites [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.

In the paper

“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.”

In the paper

“A polymer-based SPE cartridge is commonly employed for PFAS analysis [6,7,9].”

What the sources say

• Not checked yetcites [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 yetcites [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 yetcites [9] Lorenzo, 2018, Analytical challenges to determine emerging persistent organic pollutants in aquatic ecosystems, Trends Anal. Chem. source

In the paper

“For ionic PFAS, instruments are similar to those used for analysis of aqueous matrices by HPLC-negative ESI-MS/MS.”

In the paper

“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].”

What the sources say

• Not checked yetcites [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

In the paper

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

In the paper

“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].”

What the sources say

• Not checked yetcites [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

In the paper

“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].”

What the sources say

• Not checked yetcites [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

In the paper

“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].”

What the sources say

• Not checked yetcites [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

In the paper

“For neutral PFAS such as FASAs, FASEs and FTOHs, atmospheric pressure chemical ionisation (APCI) and atmospheric pressure photoionisation (APPI) have also been tested [45].”

What the sources say

• Not checked yetcites [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

In the paper

“Simultaneous analyses of PFAS, pharmaceuticals, personal care products and pesticides were developed using these types of SPE cartridges [15].”

What the sources say

• Not checked yetcites [15] Tröger, 2018, Micropollutants in drinking water from source to tap - method development and application of a multiresidue screening method, Sci. Total Environ. source

In the paper

“A few studies used Orbitrap-MS [68] or TOF-MS [17].”

What the sources say

• Not checked yetcites [68] Ruan, 2015, Identification of novel polyfluorinated ether sulfonates as PFOS alternatives in municipal sewage sludge in China, Environ. Sci. Technol. source
• Not checked yetcites [17] Newton, 2017, Novel polyfluorinated compounds identified using high resolution mass spectrometry downstream of manufacturing facilities near Decatur, Alabama, Environ. Sci. Technol. source

In the paper

“LLE is yet another technique frequently applied as a clean-up method for PFAS analysis.”

In the paper

“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].”

What the sources say

• Not checked yetcites [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

In the paper

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

In the paper

“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].”

What the sources say

• Not checked yetcites [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

In the paper

“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].”

What the sources say

• Not checked yetcites [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.

In the paper

“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].”

What the sources say

• Not checked yetcites [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

In the paper

“revealing that 6:2 and 8:2 Cl-PFESA and PFOS have bioaccumulated and been biomagnified in the marine ecosystem.”

What the sources say

• Not checked yetcites [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

In the paper

“6:2 Cl-PFESA was detected in 88%e95% of samples.”

What the sources say

• Not checked yetcites [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

In the paper

“concluded that nail was an ideal matrix for PFOS biomonitoring [89].”

What the sources say

• Not checked yetcites [89] Wang, 2018, Occurrence of perfluoroalkyl substances in matched human serum, urine, hair and nail, J. Environ. Sci. source

In the paper

“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].”

What the sources say

• Not checked yetcites [12] Jian, 2018, A short review on human exposure to and tissue distribution of per- and polyfluoroalkyl substances (PFASs), Sci. Total Environ. source

In the paper

“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.”

What the sources say

• Not checked yetcites [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 yetcites [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 yetcites [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

In the paper

“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].”

What the sources say

• Not checked yetcites [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

In the paper

“In-source fragmentation flagging scans for anionic PFAS have proved effective in some recent studies [18].”

What the sources say

• Not checked yetcites [18] Liu, 2018, Nontarget mass spectrometry reveals new perfluoroalkyl substances in fish from the Yangtze River and Tangxun Lake, China, Environ. Sci. Technol. source

In the paper

“PFPiAs were detected in all animals at levels 1e2 orders of magnitude lower than those of PFCAs and PFSAs”

What the sources say

• Not checked yetcites [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

In the paper

“Most recently, the technique was applied to detect PFAS in cosmetics [98].”

What the sources say

• Not checked yetcites [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

In the paper

“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.”

In the paper

“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].”

What the sources say

• Not checked yetcites [100] Dauchy, 2019, Deep seepage of per- and polyfluoroalkyl substances through the soil of a firefighter training site and subsequent groundwater contamination, Chemosphere source

In the paper

“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.”

In the paper

“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.”

In the paper

“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].”

What the sources say

• Not checked yetcites [99] Houtz, 2012, Oxidative conversion as a means of detecting precursors to perfluoroalkyl acids in urban runoff, Environ. Sci. Technol. source

In the paper

“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.”

In the paper

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

In the paper

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