Continuing regulatory scrutiny of per- and polyfluoroalkyl substances (PFASs) has resulted in usage of fluorinated alternative products. Featured analytical methodologies are thus emerged recently ...for the identification of novel PFAS contaminants in environmental and biological matrices. In this review, protocols for tracing compositions of unidentified organofluorine components are summarized. Data-mining and chemical recognition techniques by high-resolution mass spectrometry are further overviewed. We also discuss knowledge gaps and future trends on separation and elucidation of emerging PFAS analogues with varied molecular structures.
•Recent advances in identification of PFAS contaminants.•Methods for tracing unidentified organofluorine and recognizing novel chemicals.•Mass balance analysis, in-silica predication, and HRMS workflow are vital.•Analytical techniques on the basis of PFAS characteristics.•Challenges and trends on analyte separation and structure elucidation.
Organophosphate esters (OPEs) are used as additives in flame retardants and plasticizers. Due to phase out of several congeners of polybrominated diphenyl ethers (PBDEs), the application of ...organophosphorus flame retardants (OPFRs) is continuously increasing over the years. As a consequence, large amounts of OPEs enter the environment. Sewage and solid waste (especially e-waste) treatment plants are the important sources of OPEs released to the environment. Other sources include emissions of OPE-containing materials and vehicle fuel into the atmosphere. OPEs are widely detected in air, dust, water, soil, sediment and sludge. To know the pollution situation of OPEs, a variety of methods on their pretreatment and determination have been developed. We discussed and compared the analytical methods of OPEs, including extraction, purification as well as GC- and LC-based determination techniques. Much attention has been paid to OPEs because some of them are recognized highly toxic to biota, and the toxicological investigations of the most concerned OPEs were summarized. Risk assessments showed that the aquatic and benthic environments in some regions are under considerable ecological risks of OPEs. Finally, we pointed out problems in the current studies on OPEs and provided some suggestions for future research.
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•Recent updates on analysis, occurrence and risk assessment of OPEs were reviewed.•Robust analytical methods for OPEs have been published.•OPEs occur in various environmental matrices at concentrations of up to ppm level.•Surface water and sediment with the most toxic OPEs in many regions are under ecological risks.
Ambient particulate matter pollution is one of the leading causes of global disease burden. Epidemiological studies have revealed the connections between particulate exposure and cardiovascular and ...respiratory diseases. However, until now, the real species of ambient ultrafine particles (UFPs) in humans are still scarcely known. Here we report the discovery and characterization of exogenous nanoparticles (NPs) in human serum and pleural effusion (PE) samples collected from non-occupational subjects in a typical polluted region. We show the wide presence of NPs in human serum and PE samples with extreme diversity in chemical species, concentration, and morphology. Through chemical multi-fingerprinting (including elemental fingerprints, high-resolution structural fingerprints, and stable iron isotopic fingerprints) of NPs, we identify the sources of the NPs to be abiogenic, particularly, combustion-derived particulate emission. Our results provide evidence for the translocation of ambient UFPs into the human circulatory system, and also provide information for understanding their systemic health effects.
Widespread environmental contamination of legacy long-chain poly- and per-fluoroalkyl substances (PFASs) has triggered chemical regulatory action and a global transitioning to alternative PFASs. More ...than 5000 PFASs are now recognized on various lists, but few have been monitored despite ample evidence of unidentified organic fluorine in human and environmental samples. Nevertheless, our review of the literature indicates that nontarget analytical methods based on high-resolution mass spectrometry have been used to discover more than 750 PFASs, belonging to more than 130 diverse classes, in strategically selected environmental samples, biofluids or commercial products. Among these reports, we summarize the analytical and data-processing strategies for nontarget PFAS discovery, identify knowledge gaps and propose new areas for method development. Discovery of emerging PFASs before they are global contaminants could mitigate future contamination if strategic techniques can be developed to prioritize some of these substances for synthesis and confirmation, further monitoring, source elucidation and hazard characterization.
•Nontarget HRMS is already proven as a powerful tool for discovery of PFASs in strategically selected samples.•Identification of PFAS-features in complex HRMS spectra is a crucial step in the workflow.•Advances in analytical methods and feature identification will likely facilitate further discoveries in background samples.•The many new PFAS discoveries require strategies to prioritize substances for further confirmation, monitoring and research.
Despite the possible occurrence of metal nanoparticles in the environment due to the discharge of engineered nanoparticles and the natural transformation of metal ions into metal nanoparticles, ...little is known about the transformation mechanism, fates, behaviors, and effects of these nanoparticles in the environment. Here, we show that dissolved organic matter (DOM) in environmental waters can mediate the reduction of ionic Ag and Au to their metallic nanoparticles under natural sunlight, suggesting that this process may be general for metals with high reduction potential. We demonstrated that the reduction was mediated by superoxide from photoirradiation of the phenol group in DOM, and the dissolved O2 significantly enhanced the formation of Ag nanoparticles. These results imply that previous knowledge about O2-induced dissolution and its effect on persistence of Ag nanoparticles should be reconsidered in a sunlit DOM-rich aqueous environment. This study can also shed light on understanding possible natural sources of Ag and Au nanoparticles in the aquatic environment, which is possibly critical in the supergene enrichment of Ag and Au.
A 6:2 chlorinated polyfluorinated ether sulfonate (6:2 Cl-PFAES) with the trade name F-53B, is an alternative to perfluorooctanesulfonate (PFOS) in electroplating industry that is uniquely used in ...China. It was developed as a mist suppressant initially in the 1970s, but the environmental behaviors and potential adverse effects of the 6:2 Cl-PFAES have only recently been investigated. In this work, the occurrence and distribution of perfluoroalkyl sulfonate (PFSA), fluorotelomer sulfonate (FTSA), and PFAES analogues were investigated in municipal sewage sludge samples collected around China. Perfluorobutane, perfluorohexane, perfluorooctane, and perfluorodecanesulfonates, 6:2 and 8:2 FTSAs, and the emerging 6:2 Cl-PFAES were detected. Moreover, 8:2 and 10:2 Cl-PFAESs were identified for the first time as new polyfluorinated contaminants using high resolution mass spectrometry. These fluorinated analytes were further quantified with the aid of commercial and laboratory-purified standards. PFOS was the predominant contaminant with a geometric mean (GM) value of 3.19 ng/g dry weight (d.w.), which was subsequently followed by 6:2 Cl-PFAES and 8:2 Cl-PFAES (GM: 2.15 and 0.50 ng/g d.w., respectively). Both 6:2 and 8:2 Cl-PFAES were positively detected as the major components in the F-53B commercial product, and discrete 6:2 Cl-PFAES/8:2 Cl-PFAES ratios in the product and sludge samples might suggest 8:2 Cl-PFAES had enhanced sorption behavior in the sludge due to the increase in hydrophobicity.
► We review recent applications of graphene-based materials in SPE and SPME. ► We review recent applications of graphene-based materials in MALDI-MS. ► We discuss challenges and perspectives of ...graphene-based sample preparation.
As a new member of the carbon family, graphene has fascinated the scientific community since its discovery. Recently, graphene also exhibited great potential to be an adsorbent in analytical sample preparation due to its exceptional properties (e.g., large surface area, π-electron-rich structure, and good thermal and chemical stability).
In this article, we review the recent applications of graphene and graphene-based materials in solid-phase extraction and solid-phase microextraction, and other sample-preparation techniques. We also cover the use of graphene as extractor and matrix in matrix-assisted laser desorption/ionization mass spectrometry.
Finally, we discuss possible challenges and future perspectives in this rapidly developing field.
Carbonyl compounds are an important class of by-products that are generated in disinfection reactions. These chemicals are ingredients contributing to toxicology in the drinking water system, the ...compositions and structures of which are worthy of attention. In this study, a chemical derivatization method based on simultaneous light/heavy isotope labeling was established for general recognition of carbonyl compounds and carbonyl disinfection by-products (DBPs) as per the humic substance reference standard (Suwannee river fulvic acid II, SRFA) before and after ozonation, chlorination, and chloramination. Decomposition of macromolecular components into polar carbonyl species was observed to be the most prominent pathway in ozone treatment due to the efficient reactivity of ozone with phenols and alkoxy aromatic rings. As a result, alteration of molecular characteristics was noticed. For instance, ozone-induced carbonyl DBPs in the highly oxygenated compound classes (0.67 ≤ O/C ≤ 1.2, 0.6 < H/C ≤ 1.5) possessed higher O/C but contained less oxygen numbers and carbon numbers. Cl/Br-carbonyl-DBPs were identified after chlorination and chloramination, and I-carbonyl-DBPs were found in ozone and chloramine treatments. Several major halogenated carbonyl homologues were further recognized, including halogenated 4-oxobutenoic acid analogues, halogenated 2,5-dioxohex-3-enoic acid analogues, and halogenated 4-cyclopentene-1,3-diones analogues. These findings illustrate the presence of abundant carbonyl DBPs in water disinfection, and hence their impacts on human health deserve further investigation.
The continuous improvement of living standards is related to higher requirements for the freshness and taste of food. For example, synthetic phenolic antioxidants (SPAs) are added to fats and fried ...foods as food additives to minimize the oxidative rancidity of oils and fats. Hence, the global use of SPAs is increasing year by year. Dibutyl hydroxytoluene is one of the widely used SPAs, often in combination with butyl hydroxyanisole or gallate SPAs. The extensive use of these compounds makes them and their transformation products to be widespread in various environmental matrices, including indoor dust, wastewater, river water, sewage sludge, and sediment, as well as human samples, such as nails and urine, at concentrations varying from nanogram per gram (ng/g) to microgram per gram (μg/g). Animal experiments have shown that high-dose SPA exposure is toxic, which may lead to DNA damage and mismatches and the development of cancerous tumors. Since the biosphere shares the same set of genetic codes, humans and animals have many identical or similar feedback mechanisms and information pathways. Therefore, the damage of SPAs to animals may also threaten human health. This review discusses the properties, occurrence, analysis, and environmental health risks of typical SPAs, including butyl hydroxyanisole, dibutyl hydroxytoluene, tert-butylhydroquinone, propyl gallate, octyl gallate, and lauryl gallate, used as food additives. In addition, AO2246, which is used in food packaging bags, is also considered. Future research directions on SPAs and their transformation products (TPs) are identified and discussed.
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•Analytical methods of SPAs and TPs based on GC and HPLC were summarized.•BHA, and BHT and its TPs are frequently detected in various environmental matrices.•Human exposure to SPAs is minor compared with the ADIs.•The lack of PNECs may cause inaccurate risk assessment of SPAs.
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