| 1. |
- Awchi, Mo, et al.
(författare)
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Development, validation, and application of a new method for the quantitative determination of monohydrogen-substituted perfluoroalkyl carboxylic acids (H-PFCAs) in surface water
- 2022
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Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 287
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Tidskriftsartikel (refereegranskat)abstract
- Per- and polyfluoroalkyl substances (PFASs) are a large and diverse class of chemicals. While some have been phased out internationally due to concerns over their human and environmental health risks, novel alternative PFASs continue to be manufactured and detected in environmental samples. The occurrence and fate of these alternatives remain poorly understood. The present study investigated the occurrence of an emerging class of PFAS alternative, the monohydrogen-substituted perfluoroalkyl carboxylic acids (H-PFCAs), in conjunction with the more well-known PFCAs. A weak anion exchange solid phase extraction-liquid chromatography tandem mass spectrometry method for quantitative determination of H-PFCAs in surface water was developed, validated, and applied on samples collected from the Netherlands. To improve chromatography, especially for short-chain (H-) PFCAs, an ion-pairing agent, tetrabutylammonium hydrogen sulphate, was used. The method was validated for linearity (R2 > 0.99), instrumental detection limits (0.01-0.09 ng/mL), method detection limits (0.03-0.75 ng/ mL), matrix effects (<20%), percent absolute- and relative recovery (57-121%), trueness (130-80%), repeatability (<20%), and within-lab reproducibility (<20%). Eleven out of fourteen PFASs showed acceptable results. Application of the newly validated method to surface water throughout the Netherlands revealed trace levels of H-PFCAs (including two new H-PFCAs) and high concentrations of PFCAs.
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| 2. |
- Yuan, Bo, et al.
(författare)
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Quantifying Short-Chain Chlorinated Paraffin Congener Groups
- 2017
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 51:18, s. 10633-10641
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Tidskriftsartikel (refereegranskat)abstract
- Accurate quantification of short-chain chlorinated paraffins (SCCPs) poses an exceptional challenge to analytical chemists. SCCPs are complex mixtures of chlorinated alkanes with variable chain length and chlorination level; congeners with a fixed chain length (n) and number of chlorines (m) are referred to as a congener group CnClm Recently, we resolved individual CnClm by mathematically deconvolving soft ionization high-resolution mass spectra of SCCP mixtures. Here we extend the method to quantifying CnClm by introducing CnClm specific response factors (RFs) that are calculated from 17 SCCP chain-length standards with a single carbon chain length and variable chlorination level. The signal pattern of each standard is measured on APCI-QTOF-MS. RFs of each CnClm are obtained by pairwise optimization of the normal distribution's fit to the signal patterns of the 17 chain-length standards. The method was verified by quantifying SCCP technical mixtures and spiked environmental samples with accuracies of 82-123% and 76-109%, respectively. The absolute differences between calculated and manufacturer-reported chlorination degrees were 0.9 to 1.0%Cl for SCCP mixtures of 49-71%Cl. The quantification method has been replicated with ECNI magnetic sector MS and ECNI-Q:Orbitrap-MS. CnClm concentrations determined with the three instruments were highly correlated (R-2 > 0.90) with each other.
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| 3. |
- Gebbink, Wouter A., et al.
(författare)
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Estimating human exposure to PFOS isomers and PFCA homologues : The relative importance of direct and indirect (precursor) exposure
- 2015
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Ingår i: Environment International. - : Elsevier BV. - 0160-4120 .- 1873-6750. ; 74, s. 160-169
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Tidskriftsartikel (refereegranskat)abstract
- Contributions of direct and indirect (via precursors) pathways of human exposure to perfluorooctane sulfonic acid (PFOS) isomers and perfluoroalkyl carboxylic acids (PFCAs) are estimated using a Scenario-Based Risk Assessment (SceBRA) modelling approach. Monitoring data published since 2008 (including samples from 2007) are used. The estimated daily exposures (resulting from both direct and precursor intake) for the general adult population are highest for PFOS and perfluorooctanoic acid (PFOA), followed by perfluorohexanoic add (PFHxA) and perfluorodecanoic acid (PFDA), while lower daily exposures are estimated for perfluorobutanoic acid (PFBA) and perfluorododecanoic acid (PFDoDA). The precursor contributions to the individual perfluoroalkyl acid (PFAA) daily exposures are estimated to be 11-33% for PFOS, 0.1-2.5% for PFBA, 3.7-34% for PFHxA, 13-64% for PFOA, 5.2-66% for PFDA, and 0.7-25% for PFDoDA (ranges represent estimated precursor contributions in a low- and high-exposure scenario). For PFOS, direct intake via diet is the major exposure pathway regardless of exposure scenario. For PFCAs, the dominant exposure pathway is dependent on perfluoroalkyl chain length and exposure scenario. Modelled PFOS and PFOA concentrations in human serum using the estimated intakes from an intermediate-exposure scenario are in agreement with measured concentrations in different populations. The isomer pattern of PFOS resulting from total intakes (direct and via precursors) is estimated to be enriched with linear PFOS (84%) relative to technical PFOS (70% linear). This finding appears to be contradictory to the observed enrichment of branched PFOS isomers in recent human serum monitoring studies and suggests that either external exposure is not fully understood (e.g. there are unknown precursors, missing or poorly quantified exposure pathways) and/or that there is an incomplete understanding of the isomer-specific human pharmacokinetic processes of PFOS, its precursors and intermediates.
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| 4. |
- Gebbink, Wouter A., et al.
(författare)
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Observation of emerging per- and polyfluoroalkyl substances (PFASs) in Greenland marine mammals
- 2016
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Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 144, s. 2384-2391
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Tidskriftsartikel (refereegranskat)abstract
- The present pilot study examined emerging per- and polyfluoroalkyl substances (PFASs), i.e., a suite of short chain perfluoroalkyl acids (PFAAs), PFAA precursors and replacement chemicals, and legacy PFASs (long chain length PFAAs) in livers from ringed seals, polar bears and, for the first time, killer whales from East Greenland collected in 2012-2013. Among the emerging PFASs, perfluorobutanesulfonic acid (PFBS) and F-53B (a chlorinated polyfluorinated ether sulfonic acid) were detected in Arctic wildlife, albeit at concentrations approximately four orders of magnitude lower compared to perfluorooctanesulfonic acid (PFOS). PFOS was positively correlated with F-53B, but not PFBS in all three species. A total of 17 PFASs were detected in killer whales, including in a mother-fetus pair, demonstrating maternal transfer. Sigma PFAS concentrations in killer whales (269 +/- 90 ng/g) were comparable to concentrations found in ringed seals (138 +/- 7 ng/g), however, an order of magnitude lower compared to concentrations found in polar bear livers (2336 +/- 263 ng/g). Patterns of long chain PFAAs in killer whales differed from the pattern in ringed seals and polar bears. Of the monitored PFAA precursors, only perfluorooctanesulfonamide (FOSA) was detected in all three species, and FOSA/PFOS ratios and isomer patterns indicated that killer whales have a potential lower metabolic capacity to degrade FOSA compared to polar bears and ringed seals.
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| 5. |
- Gebbink, Wouter A., et al.
(författare)
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Perfluoroalkyl acids and their precursors in Swedish food : The relative importance of direct and indirect dietary exposure
- 2015
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Ingår i: Environmental Pollution. - : Elsevier BV. - 0269-7491 .- 1873-6424. ; 198, s. 108-115
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Tidskriftsartikel (refereegranskat)abstract
- We analyzed food market basket samples obtained in Sweden from 1999, 2005, and 2010 for perfluoroallcyl acids (PFAAs) and a range of precursor compounds. Perfluorooctane sulfonic acid (PFOS) precursors were detected in all food year pools with the highest concentrations in 1999. Six polyfluoroalkyl phosphate diesters (diPAPs, 4:2/6:2, 6:2/6:2, 6:2/8:2, 8:2/8:2, 6:2/10:2, and 10:2/10:2) were detected in the year pools with the highest Sigma diPAP concentrations in 1999 and 2005. All precursors were predominantly found in meat, fish, and/or eggs based on analysis of individual food groups from 1999. Based on year pools, PFOS precursors contributed between 4 and 1% as an indirect source to total dietary PFOS intakes between 1999 and 2010. Perfluorohexanoic acid (PFHxA) exposure originated entirely from diPAPs, whereas for perfluorooctanoic acid (PFOA) and perfluorodecanoic acid (PFDA), diPAPs contributed between 1 and 19% to total exposure. The lowest precursor contributions were generally seen in food samples from 2010.
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| 6. |
- Gebbink, Wouter A., et al.
(författare)
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Perfluoroalkyl Acids (PFAAs) and Selected Precursors in the Baltic Sea Environment : Do Precursors Play a Role in Food Web Accumulation of PFAAs?
- 2016
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 50:12, s. 6354-6362
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Tidskriftsartikel (refereegranskat)abstract
- The present study examined the presence of perfluoroalkyl acids (PFAAs) and selected precursors in the Baltic Sea abiotic environment and guillemot food web, and investigated the relative importance of precursors in food web accumulation of PFAAs. Sediment, water, zooplankton, herring, sprat, and guillemot eggs were analyzed for perfluoroalkane sulfonic acids (PFSAs; C-4,C-6,C-8,C-10) and perfluoroalkyl carboxylic acids (PFCAs; C6-15) along with six perfluorooctane sulfonic acid (PFOS) precursors and 11 polyfluoroalkyl phosphoric acid diesters (diPAPs). FOSA, FOSAA. and its methyl and ethyl derivatives (Me- and EtFOSAA), and 6:2/6:2 diPAP were detected in sediment and water. While FOSA and the three FOSAAs were detected in all biota, a total of nine diPAPs were only detected in zooplankton. Concentrations of PFOS precursors and diPAPs exceeded PFOS and PFCA concentrations, respectively, in zooplankton, but not in fish and guillemot eggs. Although PFOS precursors were present at all trophic levels, they appear to play a minor role in food web accumulation of PFOS based on PFOS precursor/PFOS ratios and PFOS and FOSA isomer patterns. The PFCA pattern in fish could not be explained by the intake pattern based on PFCAs and analyzed precursors, that is, diPAPs. Exposure to additional precursors might therefore be a dominant exposure pathway compared to direct PFCA exposure for fish.
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| 7. |
- Gebbink, Wouter A., et al.
(författare)
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Polyfluoroalkyl phosphate esters and perfluoroalkyl carboxylic acids in target food samples and packaging - method development and screening
- 2013
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Ingår i: Environmental Science and Pollution Research. - : Springer Science and Business Media LLC. - 0944-1344 .- 1614-7499. ; 20:11, s. 7949-7958
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Tidskriftsartikel (refereegranskat)abstract
- Polyfluoroalkyl phosphate mono-, di-, and tri-esters (mono-, di-, and triPAPs) are used to water- and grease-proof food packaging materials, and these chemicals are known precursors to perfluoroalkyl carboxylic acids (PFCAs). Existing analytical methods for PAPs lack sample clean-up steps in the sample preparation. In the present study, a method based on ultra performance liquid chromatography coupled to tandem mass spectrometry (UPLC/MS/MS) was developed and optimized for the analysis of mono-, di-, and triPAPs, including a clean-up step for the raw extracts. The method was applied to food samples and their PAP-containing packaging materials. The optimized UPLC/MS/MS method enabled the separation and identification of a total of 4 monoPAPs, 16 diPAPs, and 7 triPAPs in the technical mixture Zonyl®-RP. For sample clean-up, weak anion exchange solid phase extraction columns were tested. PAPs standard solutions spiked onto the columns were separated into a fraction containing neutral compounds (triPAPs) and a fraction with ionic compounds (mono- and diPAPs) with recoveries between 72–110 %. Method limits of quantification for food samples were in the sub to low picogram per gram range. For quantitative analysis of PAPs, compound-specific labeled internal standards showed to be essential as sorption and matrix effects were observed. Mono-, di-, and/or triPAPs were detected in all food packaging materials obtained from the Swedish market. Up to nine diPAPs were detected in the food samples, with the 6:2/6:2 and 6:2/8:2 diPAPs as the dominant compounds. DiPAP concentrations in the food samples ranged from 0.9 to 36 pg/g, which was comparable to individual PFCA concentrations in the same samples. Consumption of food packed in PAP-containing materials could be an indirect source of human exposure to PFCAs.
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| 8. |
- Gebbink, Wouter A., et al.
(författare)
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Temporal changes (1997-2012) of perfluoroalkyl acids and selected precursors (including isomers) in Swedish human serum
- 2015
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Ingår i: Environmental Pollution. - : Elsevier BV. - 0269-7491 .- 1873-6424. ; 199, s. 166-173
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Tidskriftsartikel (refereegranskat)abstract
- Concentrations (including isomer patterns) and temporal changes (1997-2012) of perfluoroalkyl acids (PFAAs) and selected perfluorooctane sulfonate (PFOS) and perfluoroalkyl carboxylic acid (PFCA) precursors were determined in serum samples from Swedish women. Perfluorooctane sulfonamide (FOSA) and perfluorooctane sulfonamidoacetic acid (FOSAA), as well as its N-methyl and N-ethyl derivatives (MeFOSAA and EtFOSAA) were consistently detected. Highest PFOS precursor concentrations were found for EtFOSAA (before year 2000) or MeFOSAA and FOSAA (after 2000). Disappearance half-lives for all PFOS precursors were shorter compared to PFOS. 4:2/6:2 and 6:2/6:2 polyfluoroalkyl phosphate diesters (diPAPs) were detected in <60% of the samples, whereas 6:2/8:2 and 8:2/8:2 diPAPs were detected in >60% of the samples, but showed no significant change in concentrations over time. Linear and sumbranched isomers were quantified separately for three PFAAs and three precursors. Significant changes between 1997 and 2012 in the % linear isomer were observed for PFOA and FOSA (increase) and PFOS (decrease).
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