Extraction and clean-up strategies for the analysis of poly- and perfluoroalkyl substances in environmental and human matrices.
ABSTRACT The rapidly expanding field of per- and polyfluorinated alkyl substances (PFASs) research has resulted in a wide range of analytical methodologies to determine the human and environmental exposure to PFASs. This paper reviews the currently applied techniques for sample pre-treatment, extraction and clean-up for the analysis of ionic and non-ionic PFASs in human and environmental matrices. Solid phase extraction (SPE) is the method of choice for liquid samples (e.g. water, blood, serum, plasma), and may be automated in an on-line set-up for (large volume) sample enrichment and sample clean-up. Prior to SPE, sample pre-treatment (filtration or centrifugation for water or protein precipitation for blood) may be required. Liquid-liquid extraction can also be used for liquid samples (and does not require above mentioned sample pretreatment). Solid-liquid extraction is the commonly applied method for solid matrices (biota, sludge, soil, sediment), but automation options are limited due to contamination from polytetrafluorethylene tubings and parts applied in extraction equipment. Air is generally preconcentrated on XAD-resins sandwiched between polyurethane foam plugs. Clean-up of crude extracts is essential for destruction and removal of lipids and other co-extractives that may interfere in the instrumental determination. SPE, (fluorous) silica column chromatography, dispersive graphitized carbon and destructive methods such as sulphuric acid or KOH treatment can be applied for clean-up of extracts. Care should be taken to avoid contamination (e.g. from sample bottles, filters, equipment) and losses of PFASs (e.g. adsorption, volatilization) during sampling, extraction and clean-up. Storage at -20 degrees C is generally appropriate for conservation of samples.
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ABSTRACT: In this work, the interior-walls decyl-perfluorinated functionalized magnetic mesoporous microspheres (F(17) -Fe(3) O(4) @mSiO(2) ) were synthesized for the first time, and applied as adsorbents to extract and concentrate perfluorinated compounds (PFCs) from water samples. The fluorous functionalized interior pore-walls contributed to the high-selective preconcentration of PFCs due to fluorous affinity; and abundant silanol groups on the exterior surface of microspheres contributed to the good dispersibility in water sample. Four kinds of PFCs were selected as model analytes, including perfluorooctanoic acid, perfluorononanoic acid, perfluorododecanoic acid, and perfluorooctane sulphonate. In addition, UHPLC-ESI/MS/MS was introduced to the fast and sensitive detection of the analytes after sample pretreatment. Important parameters of the extraction procedure were optimized, including salinity, eluting solvent, the amount of F(17) -Fe(3) O(4) @mSiO(2) microspheres, and extraction time. The optimized procedure took only 10 min to extract analytes with high recoveries and merely 800-μL acetonitrile to elute analytes from the magnetic adsorbents. Validation experiments showed good linearity (0.994-0.998), precision (2.6-7.6%), high recovery (93.4-105.7%) of the proposed method, and the limits of detection were from 0.008 to 0.125 μg/L. The F(17) -Fe(3) O(4) @mSiO(2) magnetic microspheres have the advantages of great dispersibility in aqueous solution, high specificity of extraction, large surface area, and efficient separation ability. The results showed that the proposed method based on F(17) -Fe(3) O(4) @mSiO(2) microspheres is a simple, fast, and sensitive tool for the analysis of PFCs in water sample.Journal of Separation Science 09/2012; 35(19):2629-36. · 2.59 Impact Factor
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ABSTRACT: Bioaccumulation of PFAS in aquatic organisms is an environmental problem of growing concern around the world. This problem has been tackled by regulatory bodies by proposing EQS for biota in EU water bodies and tolerable daily intake for food. The introduction of regulatory limits requires the availability of harmonised and validated analytical methods of sufficient sensitivity. This paper reviews recent advances in analytical methods for analysis of PFAS in aquatic organisms. The methods available for biota analysis are mostly based on three extraction procedures: ion-pair extraction, solvent liquid extraction, and alkaline digestion. The resulting extracts are then subjected to different clean-up or enrichment steps on solid adsorbents, for example graphitized carbon black, C(18), and WAX phases. All methods reviewed in this work give reliable results but are partially validated only, because of the lack of certified reference materials and regular interlaboratory exercises. The few interlaboratory exercises performed on real unspiked samples did not afford satisfactory results for PFAS other than PFOS, especially for matrices with high lipid content, for example mussels. The reasons for those partially negative results have been identified, and can mainly be attributed to calibration procedures and availability and purity of standards. The urgent need for certified reference materials for this type of analysis is emphasized.Analytical and Bioanalytical Chemistry 10/2012; · 3.66 Impact Factor
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ABSTRACT: The distribution of polyfluoroalkyl compounds (PFCs) in the dissolved and particulate phase and their discharge from the river Elbe into the North Sea were studied. The PFCs quantified included C4-C8 perfluorinated sulfonates (PFSAs), 6:2 fluorotelomer sulfonate (6:2 FTS), C6 and C8 perfluorinated sulfinates (PFSiAs), C4-C12 perfluorinated carboxylic acids (PFCAs), perfluoro-3,7-dimethyl-octanoic acid (3,7m2-PFOA), perfluorooctane sulfonamide (FOSA), and n-ethyl perfluroctane sulfonamidoethanol (EtFOSE). PFCs were mostly distributed in the dissolved phase, where perfluorooctanoic acid (PFOA) dominated with 2.9–12.5 ng/L. In the suspended particulate matter FOSA and perfluorooctane sulfonate (PFOS) showed the highest concentrations (4.0 ng/L and 2.3 ng/L, respectively). The total flux of ΣPFCs from the river Elbe was estimated to be 802 kg/year for the dissolved phase and 152 kg/year for the particulate phase. This indicates that the river Elbe acts as a source of PFCs into the North Sea. However, the concentrations of perfluorobutane sulfonate (PFBS) and perfluorobutanoic acid (PFBA) in the North Sea were higher than that in the river Elbe, thus an alternative source must exist for these compounds.Frontiers of Environmental Science & Engineering in China 04/2012; 3(2):152-170. · 0.75 Impact Factor