Collection of Airborne Fluorinated Organics and Analysis by Gas Chromatography/Chemical Ionization Mass Spectrometry
Department of Chemistry, University of Toronto, Toronto, Ontario, CanadaAnalytical Chemistry (Impact Factor: 5.64). 03/2002; 74(3):584-90. DOI: 10.1021/ac015630d
The ubiquitous detection of perfluorooctane sulfonate (PFOS) in humans and animals has produced a need for sensitive and compound-specific analytical methods to determine the environmental distribution of fluorinated organic contaminants. A suite of potential PFOS precursors (sulfonamides) and fluorotelomer alcohols (FTOHs) were separated by gas chromatography and detected by chemical ionization mass spectrometry (GC/CI-MS). Full-scan spectra were collected in both positive and negative chemical ionization (PCI and NCI, respectively) mode to determine retention time windows and fragmentation patterns. In selected ion monitoring (SIM) mode, instrumental detection limits ranged from 0.2 to 20 pg for individual analytes, depending on ionization mode. PCI mode was preferred for routine analysis because of the simple mass spectra produced, typified by the presence of a major molecular ion [M + H]+. High-volume air samplers collected gaseous and particle-bound fluoroorganics on composite media consisting of XAD-2, polyurethane foam (PUF), and quartz-fiber filters. The combined collection efficiency for individual analytes was 87 to 136% in breakthrough experiments. Application of the method to the analysis of ambient air from urban and rural sites confirmed the presence of six novel fluorinated atmospheric contaminants at picogram per meter3 concentrations. Low concentrations of fluoroorganics were consistently detected in blanks (<4 pg m(-3)); however, this did not prevent confirmation or quantification of environmental concentrations.
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- "Analytical methods for neutral PFAS (volatile FTOHs and FOSAs/FOSEs) in environmental and indoor air include mainly gas chromatography coupled to mass spectrometry with chemical ionization (GC/CI–MS) usually in positive mode (PCI) because it produced the molecular ion [M + H] + , and one or two characteristic fragment ions for all FTOHs and FOSEs with the exception of FOSAs for which only one ion could be detected in PCI . Therefore, confirmation of FOSAs in samples is always performed in negative ion chemical ionization (NICI) mode, wherein three fragments can be monitored . In contrast, electronic ionization (EI) is not frequently used because of the low intensity of the molecular ions and the lack of specific fragments. "
ABSTRACT: Ionization and in source-fragmentation behavior of four fluorotelomer alcohols (FTOH) (4:2 FTOH, 6:2 FTOH, 8:2 FTOH and 10:2 FTOH) and four N-alkyl fluorooctane sulfonamides/-ethanols (N-MeFOSA, N-EtFOSA, N-MeFOSE and N-EtFOSE) by APCI has been studied and compared with the traditionally used EI and CI. Protonated molecule was the base peak of the APCI spectrum in all cases giving the possibility of selecting it as a precursor ion for MS/MS experiments. Following, CID fragmentation showed common product ions for all FOSAs/FOSEs (C4F7 and C3F5). Nevertheless, the different functionality gave characteristic pattern fragmentations. For instance, FTOHs mainly loss H2O+HF, FOSAs showed the losses of SO2 and HF while FOSEs showed the losses of H2O and SO2. Linearity, repeatability and LODs have been studied obtaining instrumental LODs between 1 and 5fg. Finally, application to river water and influent and effluent waste water samples has been carried out in order to investigate the improvements in detection capabilities of this new source in comparison with the traditionally used EI/CI sources. Matrix effects in APCI have been evaluated in terms of signal enhancement/suppression when comparing standards in solvent and matrix. No matrix effects were observed and concentrations found in samples were in the range of 1-100pgL(-1) far below the LODs achieved with methods previously reported. Unknown related perfluoroalkyl substances, as methyl-sulfone and methyl-sulfoxide analogues for FTOHs, were also discovered and tentatively identified. Copyright © 2015 Elsevier B.V. All rights reserved.
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- "The latter method was later optimized to avoid solvent-induced response enhancements, which resulted in instrumental limits of detection of <0.2 pg . In earlier work on determination of airborne fluorinated organics kit was shown that both positive and negative modes of chemical ionization were useful for the determination of all target analytes . "
ABSTRACT: Perfluoroalkyl substances (PFASs) are proliferated into the environment on a global scale and present in the organisms of animals and humans even in remote locations. Persistent organic pollutants of that kind therefore have stimulated substantial improvement in analytical methods. The aim of this review is to present recent achievements in PFASs determination in various matrices with different methods and its comparison to measurements of Total Organic Fluorine (TOF). Analytical methods used for PFASs determinations are dominated by chromatography, mostly in combination with mass spectrometric detection. However, HPLC may be also hyphenated with conductivity or fluorimetric detection, and gas chromatography may be combined with flame ionization or electron capture detection. The presence of a large number of PFASs species in environmental and biological samples necessitates parallel attempts to develop a total PFASs index that reflects the total content of PFASs in various matrices. Increasing attention is currently paid to the determination of branched isomers of PFASs, and their determination in food. Figure The aim of this review is to present recent achievements in perfluoroalkyl substances (PFASs) determination in various matrices with different methods and its comparison to measurements of Total Organic Fluorine (TOF). Increasing attention is currently paid to the determination of branched isomers of PFASs, and their determination in food.
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- "FTOHs are volatile, not very soluble in water (carbon chain-length dependent) in the absence of a sorbing medium (Liu and Lee, 2005) and have a tendency to be adsorbed strongly to solid matters such as household dusts (Strynar and Lindstrom, 2008), soils or activated sludge (Liu and Lee, 2005, 2007; Wang et al., 2005a). Field monitoring studies have detected FTOHs in the troposphere at concentrations ranging from 7 to 196 pg/m 3 (Martin et al., 2002) and averaged 87 pg/m 3 (Dreyer et al., 2009) with 6:2 and 8:2 FTOHs in majority. The major source of environmental FTOHs has been postulated to come from the residual unreacted FTOH present in commercial products (Ellis et al., 2003). "
ABSTRACT: Fluorotelomer alcohols [FTOHs, F(CF(2) )(n) CH(2) CH(2) OH, n = 4, 6, and 8] are emerging environmental contaminants. Biotransformation of FTOHs by mixed bacterial cultures has been reported; however, little is known about the microorganisms responsible for the biotransformation. Here we reported biotransformation of FTOHs by two well-studied Pseudomonas strains: Pseudomonas butanovora (butane oxidizer) and Pseudomonas oleovorans (octane oxidizer). Both strains could defluorinate 4:2, 6:2, and 8:2 FTOHs, with a higher degree of defluorination for 4:2 FTOH. According to the identified metabolites, P. oleovorans transformed FTOHs via two pathways I and II. The pathway I led to the production of x:2 ketone [dominant metabolite, F(CF(2) )(x) C(O)CH(3) ; x = n - 1, n = 6 or 8], x:2 sFTOH [F(CF(2) )(x) CH(OH)CH(3) ], and perfluorinated carboxylic acids (PFCAs, perfluorohexanoic, or perfluorooctanoic acid). The pathway II resulted in the formation of x:3 polyfluorinated acid [F(CF(2) )(x) CH(2) CH(2) COOH] and relatively minor shorter-chain PFCAs (perfluorobutyric or perfluorohexanoic acid). Conversely, P. butanovora transformed FTOHs by using the pathway I, leading to the production of x:2 ketone, x:2 sFTOH, and PFCAs. This is the first study to show that individual bacterium can bio-transform FTOHs via different or preferred transformation pathways to remove multiple CF(2) groups from FTOHs to form shorter-chain PFCAs. Biotechnol. Bioeng. © 2012 Wiley Periodicals, Inc.
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