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Differences in the isomer composition of perfluoroctanesulfonyl (PFOS) derivatives
Journal article

Differences in the isomer composition of perfluoroctanesulfonyl (PFOS) derivatives

Sandhya M Vyas, Izabela Kania-Korwel and Hans-Joachim Lehmler
Journal of environmental science and health. Part A, Toxic/hazardous substances & environmental engineering, Vol.42(3), pp.249-255
03/01/2007
DOI: 10.1080/10934520601134031
PMID: 17365291

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Abstract

Perfluorooctanesulfonyl (PFOS)-based materials and related compounds are an emerging group of environmental pollutants. Perfluorooctanesulfonyl fluoride, the key intermediate for the production of these materials, was manufactured by an electrochemical fluorination process that resulted in complex mixtures containing linear and branched PFOS derivatives and other perfluorinated compounds. This study uses 19 F-NMR spectroscopy to investigate differences in the composition between commercial samples of PFOS and PFBS (perfluorobutanesulfonyl) derivatives. While PFBS derivatives, which are under evaluation as substitutes for PFOS-based materials, contained no detectable levels of branched impurities, all PFOS derivatives contained significant levels of branched and other impurities. Analysis of the NMR data reveals that PFOS fluorides typically have a higher content of internally branched and similar levels of isopropyl branched PFOS isomers compared to PFOS potassium salts. Furthermore, the isomer distribution of PFOS derivatives may vary depending on their source. These findings suggest that it is important to determine the isomer composition of PFOS samples used in both environmental and toxicological studies.
Fluorinated surfactants perfluorooctanesulfonyl fluoride perfluorooctanesulfonic acid F-NMR analysis PFOS

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