| Abstract
| - Detection of perfluorocarboxylate anions (PFCAs), such asperfluorooctanoate (C7F15COO-, PFOA), at ng/g levels inhuman tissues has engendered public scrutiny of industrialfluorochemicals. Routes of PFCA exposure for the generalhuman population are likely diverse given direct (industriallyproduced) and indirect (production from precursororganofluorines) sources. Major industrial production oforganofluorines, including PFCAs, stems from eitherelectrochemical fluorination (ECF) or telomerization. ECFproducts are a mixture of structural isomers (linear andbranched perfluoroalkyls) and telomerization products areassumed to have one perfluorocarbon arrangement,typically linear. The objective of this research was toinvestigate structural isomer patterns of PFCAs in humanblood. Volatile derivatives of PFCAs in human blood wereanalyzed by GC-(NCI)-MS for quantitation and isomers.PFOA was the dominant PFCA (mean 4.4 ng/g). Blood serumisomer profiles consisted of predominantly (mean ∼98%)the linear isomer for each PFCA (C8−C11). There weresimilarities in branched isomer patterns of an ECF PFOAstandard with both PFOA and PFNA in blood. Direct exposureto ECF PFOA, which has a legacy of production for usesin fluoropolymer industries, is postulated to be a source ofthe observed branched isomer pattern. Predominance oflinear PFCA isomers and the [even PFCA] > [odd PFCA]concentration trend in blood is suggestive of additionalinput from a strictly linear perfluoroalkyl source.
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