Examining the effects of analytical replication on data quality in a non-targeted analysis experiment.

This review follows the PRISMA guidelines to provide a systematic review of 115 peer reviewed articles that used non-targeted analysis (NTA) methods to detect per- and polyfluoroalkylated substances (PFAS). This literature highlights the significant positive impact of NTA in understanding PFAS in the environment. Within the literature a geographical bias exists, with most NTA studies (∼60%) conducted in the United States and China. Future studies in other regions (such as South America and Africa) are needed to gain a more global understanding. More research is required in marine environments and the atmosphere, as current studies focus mainly on freshwater, groundwater, soil, and sediments. The majority of studies focus on measuring PFAS in the environment, rather than in commercial products (with the exception of AFFF). Non-lethal blood sampling has been successful for NTA in humans and wildlife, but additional biomonitoring studies are required on exposed cohorts to understand health risks and PFAS biotransformation pathways. NTA methods mostly use liquid chromatography and negative ionisation, which biases the literature towards the detection of specific PFAS. Despite improvements in data reporting and quality assurance and control (QA/QC) procedures, factors such as false negative and false positive rates are often overlooked, and many NTA workflows remain highly subjective. Perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkyl sulfonic acids (PFSAs) are the most detected PFAS classes, identified in over 80% of NTA studies, and are common in routine monitoring. However, our review identified >1000 PFAS from a total of 382 different PFAS classes, with over 300 classes found in fewer than 5% of studies. This highlights the variety of different PFAS present in the environment, and the limitations of relying solely on targeted methods. Future monitoring programs and regulations would benefit from considering NTA methods to provide more comprehensive information on PFAS present in the environment.

Per- and polyfluoroalkyl substances (PFAS) are a class of thousands of man-made chemicals that are persistent and highly stable in the environment. Fish consumption has been identified as a key route of PFAS exposure for humans. However, routine fish monitoring targets only a handful of PFAS, and non-targeted analyses have largely only evaluated fish from heavily PFAS-impacted waters. Here, we evaluated PFAS in fish fillets from recreational and drinking water sources in central North Carolina to assess whether PFAS are present in these fillets that would not be detected by conventional targeted methods. We used liquid chromatography, ion mobility spectrometry, and mass spectrometry (LC-IMS-MS) to collect full scan feature data, performed suspect screening using an in-house library of 100 PFAS for high confidence feature identification, searched for additional PFAS features using non-targeted data analyses, and quantified perfluorooctanesulfonic acid (PFOS) in the fillet samples. A total of 36 PFAS were detected in the fish fillets, including 19 that would not be detected using common targeted methods, with a minimum of 6 and a maximum of 22 in individual fish. Median fillet PFOS levels were concerningly high at 11.6 to 42.3 ppb, and no significant correlation between PFOS levels and number of PFAS per fish was observed. Future PFAS monitoring in this region should target more of these 36 PFAS, and other regions not considered heavily PFAS contaminated should consider incorporating non-targeted analyses into ongoing fish monitoring studies.

Per- and polyfluoroalkyl substances (PFAS) are an emerging class of toxic environmental contaminants. Over 7500 PFAS exist, but reference standards are available for less than 2% of compounds. Nontargeted analysis using liquid chromatography-high-resolution tandem mass spectrometry is therefore an essential technique for increasing the analytical coverage of PFAS present in environmental samples. However, typical nontargeted data analysis is laborious and has a steep learning curve. Recently, FluoroMatch, a new open source, vendor neutral software, was published specifically for automating data processing for nontargeted analysis of PFAS and generating PFAS libraries. Here, we analyze soil contaminated with PFAS based aqueous film forming foam (AFFF) and compare the results produced by data analysis workflows using FluoroMatch and Compound Discoverer, an established nontargeted analysis program. High-confidence PFAS annotations were nearly identical between the methods, with 27 out of 32 compounds found using both Compound Discoverer and the modular version of FluoroMatch. Twenty-two high-confidence annotations were found using the comprehensive FluoroMatch Flow. The FluoroMatch method was faster and required significantly less manual curation than the Compound Discoverer method. Both platforms produced high-quality data that were useful for assessing PFAS contamination in the soil.

Per- and polyfluoroalkyl substances (PFAS) are globally recognised as persistent organic pollutants of substantial environmental and public health concern as a result of their toxicity, bioaccumulation, and chemical stability. The detection of PFAS at trace and ultra-trace levels in complex matrices remains an analytical challenge due to the presence of numerous unknown analogues and the diverse physicochemical properties of PFAS. This systematic review critically evaluates 55 peer-reviewed studies published between 2010 and 2025 that focus on analytical techniques for quantifying and identifying PFAS in environmental and biological samples. The assessment follows the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and compares the performance of major analytical platforms, including liquid chromatography tandem mass spectrometry (LC–MS/MS), ultra-high-performance liquid chromatography high-resolution mass spectrometry (UHPLC–HRMS), gas chromatography mass spectrometry (GC–MS), extractable/adsorbable organofluorine (EOF/AOF), surface-enhanced Raman spectroscopy (SERS), and electrochemical or hybrid sensor-based approaches. LC–MS/MS and UHPLC–HRMS remain the gold standards for quantitative and non-target PFAS analysis, respectively, while emerging spectroscopic and electrochemical methods offer rapid, portable, and cost-effective alternatives. Molecularly imprinted polymers, deep eutectic solvents, and bubble-assisted extraction are among the sample preparation advancements that have further enhanced environmental sustainability and sensitivity. The review highlights the need for standardized QA/QC protocols, certified reference materials, and inter-laboratory harmonization. Integration of artificial intelligence, green chemistry, and multi-platform detection systems represents the future direction for comprehensive PFAS monitoring and exposure assessment. Keywords: Per- and Polyfluoroalkyl Substances, Mass Spectroscopy, Non-target analysis, Surface-Enhanced Raman Spectroscopy, Environmental monitoring.

Environmental health concerns over per- and polyfluoroalkyl substances (PFAS) have prompted public health laboratories to pursue monitoring studies determining PFAS occurrences. Select laboratories have begun implementing non-targeted analysis (NTA) methods to address the disparity between the few (< 100) PFAS typically measured using targeted analyses and the thousands of known PFAS. While NTA can provide a more comprehensive understanding of PFAS occurrence, significant barriers prevent its widespread adoption in public health laboratories. Notable barriers include a lack of harmonized guidance, standardized methods, and workflows that enable robust NTA application. EPA's Office of Research and Development has been working to overcome these barriers as part of technical collaborations with state environmental and public health laboratories. As a product of these efforts, ORD has developed the ENTAiLS Toolkit, a publicly available compilation of best practices and an open-source data processing workflow for PFAS NTA studies. The ENTAiLS Toolkit offers NTA practitioners comprehensive guidance and integrated tools that can aid the identification and characterization of PFAS in drinking water resources.

Electronic waste (e-waste) is a growing solid waste stream with largely undisclosed and poorly characterized fluorinated constituents. We evaluated per- and polyfluoroalkyl substances (PFAS) leachability from four e-waste components (phone screens, phone plastics, capacitors, and Lithium-ion batteries) using a 30-day deionized water leaching test. PFAS were extracted by solid-phase extraction using weak anion exchange (WAX) cartridges and analyzed with a liquid chromatography triple-quadrupole mass spectrometer. In addition, the PFAS chemical profiles of e-waste components were characterized by non-targeted analysis. Leachable sums of detected PFAS (∑PFAS) were highest in phone screens (1739-1932 ng·kg-1) and phone plastics (1575-2197 ng·kg-1) and an order of magnitude lower in Lithium-ion batteries (148-158 ng·kg-1) and capacitors (147-243 ng·kg-1). Short-chain perfluoroalkyl acids (PFAAs) (e.g., PFBA, PFHxA) and legacy acids (e.g., PFOA, PFNA) were more prevalent in phone screens/plastics, whereas capacitors and batteries showed mixed sulfonate/carboxylate patterns (PFOS, PFHxS, and 6:2 FTS). Although capacitors and Lithium-ion batteries contained essential PFAS with high hazard potential at trace levels, phone screens and phone plastics pose a greater risk per mass due to higher ∑PFAS levels and larger volumes. Non-targeted analysis using Orbitrap Astral revealed CF2/CF2O homologous trends (confidence levels 2-3) with corroborating targeted findings. These findings highlight the need for PFAS-free alternatives, the disclosure of fluorinated additives, and stronger end-of-life management strategies to prevent PFAS releases from e-waste.

“Simultaneous targeted and non-targeted analysis of per- and polyfluoroalkyl substances in environmental samples by liquid chromatography-ion mobility-quadrupole time of flight-mass spectrometry and mass defect analysis”

Monitoring contamination from per- and polyfluoroalkyl substances (PFASs) in water systems impacted by aqueous film-forming foams (AFFFs) typically addresses a few known PFAS groups. Given the diversity of PFASs present in AFFFs, current analytical approaches do not comprehensively address the range of PFASs present in these systems. A suspect-screening and nontarget analysis (NTA) approach was developed and applied to identify novel PFASs in groundwater samples contaminated from historic AFFF use. A total of 88 PFASs were identified in both passive samplers and grab samples, and these were dominated by sulfonate derivatives and sulfonamide-derived precursors. Several ultrashort-chain (USC) PFASs (≤C3) were detected, 11 reported for the first time in Australian groundwater. Several transformation products were identified, including perfluoroalkane sulfonamides (FASAs) and perfluoroalkane sulfinates (PFASis). Two new PFASs were reported (((perfluorohexyl)sulfonyl)sulfamic acid; m/z 477.9068 and (E)-1,1,2,2,3,3,4,5,6,7,8,8,8-tridecafluorooct-6-ene-1-sulfonic acid; m/z 424.9482). This study highlights that several PFASs are overlooked using standard target analysis, and therefore, the potential risk from all PFASs present is likely to be underestimated.

Per- and polyfluoroalkyl substances (PFASs) are a large group of synthetic chemicals characterized by strong carbon-fluorine bonds. These compounds have been used in many industrial and consumer applications, including polymer production, surfactants, fire-fighting foams (AFFFs), and products like non-stick cookware, textiles, and carpets. Some PFASs, such as perfluorocarboxylic acids (PFCAs) and sulfonic acids (PFSAs) like PFOA and PFOS, are known for their persistence in the environment, ability to accumulate in living organisms, and potential health risks. While various countries have implemented regulations, only a fraction of PFASs are routinely monitored due to the limited availability of analytical standards required for detection and quantification. To address this, 53 PFASs were synthesized, including 20 deuterated mass-labelled analogues, to support the development of advanced chromatographic screening methods. These compounds belong to 14 different chemical classes, focusing on short-chain (C4 and C6) perfluoroalkane sulfonamide derivatives, such as N-alkyl sulfonamidoacetic acids (FASAA) and N-alkyl sulfonamidoethanols (FASE). These were selected because they are potential precursors to more persistent PFASs and are relatively stable in environmental samples. Purification was achieved through multiple recrystallizations, especially for N-alkyl perfluoroalkane sulfonamides with methyl, ethyl, or benzyl groups. These intermediates were purified as solids, and the removal of isomers was confirmed by fluorine-NMR. Final products were obtained via alkylation of intermediates. For benzyl-containing intermediates, hydrogenation was used to remove the protecting group. The synthesized standards were incorporated into liquid and gas chromatography–mass spectrometry methods alongside commonly monitored PFASs, including perfluoroalkyl acids, sulfonic acids, ether-PFASs, and fluorotelomer alcohols. Target screening was performed on textile and surface water samples. Textiles, especially carpets and water-resistant fabrics, often contain PFASs used for their water and oil repellency. Surface water samples from the Netherlands were chosen due to previously reported PFAS contamination. In textiles, particularly carpets, C4-based sulfonamides with a methyl group on the nitrogen atom were frequently detected. These included compounds such as MeFBSE, MeFBSEA, MeFBSAA, FBSE, and FBSA. Interestingly, long-chain sulfonamides like MeFOSE and EtFOSE were not found. Fluorotelomer alcohols, especially 6:2 FTOH, contributed significantly to the total PFAS content, although overall concentrations were low. Surface water samples (25 total) from various Dutch locations were also analyzed. PFASs were detected in all samples, with four sites showing concentrations above 70 ng/L. The dominant compounds were short-chain PFCAs and PFSAs like PFBA and PFBS, which made up 87% of the total PFAS load. MeFBSAA was detected in many samples and was particularly high (53.1 ng/L) in one sample from Tilburg—exceeding even PFOS and PFOA levels. This suggests possible local contamination, possibly from a wastewater treatment plant, though further investigation is needed. To identify additional unknown PFASs, a non-targeted analysis using ion mobility mass spectrometry (timsTOF) was performed on selected water samples. This method provides an extra identification parameter—collision cross section (CCS)—to improve confidence in compound identification. Data were processed with MetaboScape, generating thousands of features. Using spectral libraries and target lists, several compounds were tentatively identified, including pharmaceuticals, pesticides with CF₃ groups, unsaturated PFOS, fluorotelomer precursors, and a lithium-ion battery-related ion. One fluorotelomer compound was confirmed at level 1 using a synthesized standard. These results highlight the critical role of having analytical standards to accurately detect and quantify PFASs. The study also shows that short-chain PFASs are increasingly present, consistent with their use as replacements for longer-chain compounds. Broader use of analytical and non-target approaches will be key to identifying more PFASs and improving environmental monitoring.

Integrating target, nontarget analysis with machine learning to illuminate PFAS characteristics and health risks in Chinese cosmetics.

Novel per- and polyfluoroalkyl substances (PFASs) have become a key issue in global environmental studies. Although several novel PFASs have been discovered in atmospheric particulate matter through nontarget analysis, information on the environmental occurrence of novel PFASs in atmospheric gaseous phases and conventional sampling techniques is somewhat deficient. Therefore, this Article describes a new type of air sampler, the cryogenic air sampler (CAS), which was used to collect all atmospheric components simultaneously. Nontarget analysis then was performed through PFASs homologue analysis. A total of 117 PFAS homologues (38 classes) were discovered, 48 of which (13 classes) were identified with confidence Level 4 or above. Eleven chlorinated perfluoropolyether alcohols (3 classes) and four chlorinated perfluoropolyether carboxylic acids (2 classes) have been reported for the first time in this Article. This Article is also the first report of 12 hydrosubstituted perfluoroalkyl carboxylates (H-PFCAs) in the atmosphere. H-PFCAs and chlorinated perfluoropolyether carboxylic acids were mainly distributed in the particular phase. These results are evidence that novel chlorinated polyether PFASs should be the focus of future study.

Per- and polyfluoroalkyl substances (PFAS) continue to increase in concentration and prevalence in the environment due to the creation of emerging PFAS and the lack of breakdown of legacy compounds. PFAS are known to both bioaccumulate and biomagnify; therefore, species higher on the food chain, such as marine mammals, are highly exposed to these chemicals. Although studies suggest that considerable maternal transfer of persistent organic pollutants occurs via lactation, data are still lacking on the temporal trends associated with PFAS exposure. In this study, we first optimized the extraction for PFAS from 5 and 1mL of goat's milk using a QuEChERS extraction method to account for precious breast milk samples that are often only available in small volumes. We then utilized a set of dolphin breastmilk samples from an individual mother across a 2-year lactation period to evaluate longitudinal trends in PFAS concentrations and profiles. Thirty PFAS were detected using a multidimensional platform combining liquid chromatography, ion mobility spectrometry, and mass spectrometry (LC-IMS-MS), and of these, 20 PFAS were detected continuously across the nursing window of 103-706days. Quantitative analysis using LC-IMS-MS specifically showed concentrations of perfluorooctanesulfonic acid (PFOS) alone surpass weekly intake recommendations, allometrically scaled to dolphins, from the European Food Safety Authority and Food Standards Australia New Zealand by more than 25-fold. PFOS, however, decreased slightly over time, possibly due to transfer from feedings. Suspect screening and non-targeted analysis also identified 12 compounds including 2 long-chained perfluorosulfonic acids not traditionally evaluated in targeted analyses, as well as the PFOS precursors, perfluoroethylcyclohexane sulfonate (PFECHS) and 2-(N-ethylperfluorooctanesulfonamido) ethyl phosphate (SAmPAP). This study therefore suggests that breastmilk is a major contributor to early-life PFAS exposure for mammals, particularly to long-chained PFAS.

Poly- and perfluoroalkyl acids (PFAAs) are a large family of widespread contaminants of worldwide concern and well-known as "forever chemicals". Direct emission of PFAAs from the fluorochemical industry is a crucial source of PFAA pollutants in the environment. This study implemented nontarget analysis and comprehensive characterization for a category of new PFAA contaminants, i.e., iodinated PFAAs (IPFAAs), in fluorochemical industry wastewater and relevant contaminated river water by liquid chromatography-high-resolution mass spectrometry with a cascade precursor ion exclusion (PIE) strategy and in-house developed data extraction and processing algorithms. A total of 26 IPFAAs (including 2 isomers of an IPFAA) were found and identified with tentative molecular structures. Semiquantification of the IPFAAs was implemented, and the total concentrations of IPFAAs were 0.16-285.52 and 0.15-0.17 μg/L in wastewater and river water, respectively. The high concentrations in association with the predicted ecotoxicities and environmental behaviors demonstrate that these IPFAAs are worthy of more concern and further in-depth research. The cascade PIE strategy along with the data extraction and processing algorithms can be extended to nontarget analysis for other pollutants beyond IPFAAs. The nontarget identification and characterization outcomes provide new understanding on the environmental occurrence and pollution status of IPFAAs from a comprehensive perspective.

BACKGROUND AND AIM: Non-targeted analysis has enabled us to screen biological samples for a broad spectrum of chemical compounds that would otherwise remain undetected with traditional targeted analytical techniques. While our previous studies have presented a number of man-made chemicals in human serum, the sources of many of these chemicals remain unknown. The aim of our study was to understand the sources of a group of chemicals, some of which are not actively biomonitored, (n=18; phenols, surfactants and per- and polyfluoroalkyl substances) identified and quantified in 300 maternal and 300 cord matched blood samples collected at delivery and analyzed with a non-targeted analysis workflow. METHODS: We matched measured concentrations in serum to questionnaire responses about participants’ use of consumer products in homes (n total = 148 questions) and evaluated their relationship using linear models. We also used an indoor environment multimedia fate model to test observed relationships by simulating concentrations of the chemicals in the carpets, furniture, dust and indoor air to evaluate the potential of exposure based on chemical mobility. RESULTS:We found strong positive correlations (r 0.5 and p-value 0.05) between concentrations in serum and carpets (installation and treatment), furniture (renovation and treatment), and floor (installation and treatment). One example where we measured widespread exposure in pregnant women is 4-nitrophenol. Our modeling calculations estimated that when 4-nitrophenol is emitted from carpets, it is expected to be resuspended and redeposited on vinyl floors and other surfaces leaving only a small fraction in the air available for inhalation (0.01 % of the total mass). Our modeling calculations also estimated that, due to its low volatility, the main route of exposure to 4-nitrophenol in the indoor environment is through dermal contact. CONCLUSIONS:Integrating non-targeted analysis with questionnaire data and multimedia modeling provided unique insights into the sources of environmental chemicals and pathways of exposure. KEYWORDS: exposome, non-targeted analysis, chemicals, exposure, modeling

Integrated wide-scope and class-specific nontarget analysis reveals a broad spectrum of organic micropollutants in an urban river.