Structural isomers of polyfluorinated di- and tri-alkylated phosphate ester surfactants present in industrial blends and in microwave popcorn bags

    26 Citations (Scopus)

    Abstract

    Introduction: In this study, we provide strategies for detecting and quantifying the structural isomers of polyfluorinated di- and tri-alkyl surfactants (PFAS) by mass spectrometry (MS). We specifically investigate polyfluorinated dialkylated phosphate ester surfactants (x:2/y:2 diPAPS, (F(CF2)xCH2CH2O-P(O)(O)--OCH2CH2(CF2)yF)) and their thioether analogues (x:2/y:2 S-diPAPS, F(CF2)xCH2CH2SCH2-C[CH2O)2P(O)(O)-]-CH2SCH2CH2(CF2)yF), which are used for industrial applications, such as oil- and water-repellent coatings on paper and board. DiPAPS have been found in human blood and are metabolised to the persistent perfluoroalkyl carboxylic acids (PFCA) in rats. Materials and methods: A microwave popcorn bag extract was analysed by ultrahigh-pressure liquid chromatography coupled to a negative electrospray ionisation-quadrupole time-of-flight MS. Results and discussion: The extract contained S-diPAPS, diPAPS and trialkylated (triPAPS) impurities. TriPAPS were also present in industrial and synthetic diPAPS standards, and were verified with an 8:2/8:2/8:2 triPAPS standard. The eight elemental compositions (m/z's) of diPAPS in the extract represent 19 precursor ion structures, and the six S-diPAPS m/z's represent at least 13 structures. The diPAPS had [M-H]- precursor ions of m/z 789, 889,...1,489 and the S-diPAPS of m/z 921, 1,021,...1,421, corresponding to fluorinated chains from C6-18. Each m/z appeared as one to three chromatographic peaks of structural isomers, where, e.g. m/z 1,189 was present as 10:2/10:2, 8:2/12:2 and 6:2/14:2 diPAPS. The isomers formed different products ions, thus only half of the m/z 1,189 diPAPS concentration was measured with one precursor ion > product ion transition. Conclusion: In general, knowledge about structural isomers of poly-alkylated PFAS is needed for the estimation of types and amounts of perfluorinated degradation products, such as PFCA from diPAPS.

    Original languageEnglish
    JournalEnvironmental Science and Pollution Research
    Volume18
    Issue number8
    Pages (from-to)1422-1432
    Number of pages11
    ISSN0944-1344
    DOIs
    Publication statusPublished - Sept 2011

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