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Congener-specific numbering systems for the environmentally relevant C 4 through C8 perfluorinated homologue groups of alkyl sulfonates, carboxylates, telomer alcohols, olefins, and acids, and their derivatives

Department of Chemistry, University of Winnipeg, Winnipeg, MB, Canada.
Journal of Environmental Science and Health Part A (Impact Factor: 1.14). 11/2008; 43(12):1391-401. DOI: 10.1080/10934520802232030
Source: PubMed

ABSTRACT We introduce a congener-specific numbering system for the C4 through C8 perfluorinated homologue groups of alkyl sulfonates, carboxylates, telomer alcohols, olefins, and acids, and their derivatives. Increasing length of the carbon chain beyond C3 leads to a corresponding rapid increase in the number of potential isomers (C4 = 4, C5 = 8, C6 = 17, C7 = 39, and C8 = 89 congeners). There is a need for clear and unambiguous chemical shorthand to ensure accuracy and consistency in the future perfluorinated alkyl substance (PFA) literature, and to correct previous misconceptions that may have restricted research efforts into developing full-congener PFA analysis. If adopted by the research community, introduction of a numbering system at this relatively early stage of investigations into the congener-specific analysis, environmental behavior, and toxicology of PFAs would not require an arduous and difficult reassignment of historical structures and naming conventions presented in the prior art. Many PFA congeners are chiral, necessitating a consideration of their enantiospecific environmental behavior and toxicology.

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    • "The structures of these isomers are n, iso, 5m, 4m, 3m, 2m, 1m, tb, 4,4m 2 , 5,3m 2 , and 5,4m 2 . While less effort has gone into the characterization of ECF PFOA, out of 39 possible PFOA isomers (Rayne et al. 2008b) it appears that n-, iso-, 5m-, 4m-, and 3m-PFOA make up 99.2% in 3M ECF standards with minor contributions (<0.8%) from 2m, tb, 4,4m 2 , 5,3m 2 , and 5,4m 2 (Loveless et al. 2006; Table 2). While other isomers are theoretically possible, these are unlikely to be present at measurable concentrations in the environment since they are virtually undetectable in the commercially manufactured material. "
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    Reviews of environmental contamination and toxicology 01/2010; 208:111-60. DOI:10.1007/978-1-4419-6880-7_2 · 3.63 Impact Factor
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    • "Of the 161 possible C 1 through C 8 congeners within each PFA class, only 8 have linear perfluoroalkyl chains. [114] As we have demonstrated in prior work, various computational approaches yield differing predictions regarding charge magnitudes and distributions on the PFA head groups within a particular class, [85] [109] [115] resulting in a current degree of ambiguity as to the role of branching on PFA head group charge distributions. Further progress in this area will require a continuing evaluation as authentic branched PFA standards become available for experimental evaluation and calibration of existing computational studies, and well as the possible extension and refinement of current computational methods to these compound classes. "
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    Journal of Environmental Science and Health Part A Toxic/Hazardous Substances & Environmental Engineering 11/2009; 44(13):1374-87. DOI:10.1080/10934520903217229 · 1.14 Impact Factor
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    • "[32] [33] [34] [35] [36] [37] software programs using the SMILES molecular formula language [38] [39] as inputs. References to PFCA and PFSA isomer patterns and congener identifications follow the framework outlined in ref. [40] . Experimental log D values for the PFCA and PFSA congeners under consideration (Figure 2) were obtained from ref. [30] . "
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