title: Linear and branched perfluorooctane sulfonate isomers in technical product and environmental samples by in-port derivatization-gas chromatography-mass spectrometry.
abstract: Perfluorooctane sulfonate (PFOS) is found globally as an environmental contaminant and is highly bioaccumulative in exposed biota including humans. However, there is a dearth of environmental information on the isomeric profile of PFOS, especially in biological samples, which requires suitable analysis methods for the identification and quantification of ultratrace amounts. In the present study, a novel method was developed that incorporates clean up by solid-phase extraction (SPE) WAX cartridges and in-port derivatization-gas chromatography-mass spectrometry (GC/MS) to identify and quantitatively determine linear PFOS (L-PFOS) and branched (monotrifluoromethyl and bistrifluoromethyl) isomers in PFOS technical product and in environmentally relevant biological samples. Tetrabutylammonium hydroxide (TBAH) was used for derivatization via an in situ pyrolytic alkylation reaction that occurred in the GC injector and generated butyl PFOS isomer derivatives. In addition to L-PFOS, ten branched PFOS isomers were identified in the technical product. The environmental relevance of branched PFOS isomers in addition to L-PFOS was evidenced by the presence of six branched and L-PFOS in representative herring gull and double-crested cormorant egg, and polar bear liver and plasma samples from the Great Lakes and Arctic, respectively. For all PFOS isomers in the technical product and biota samples the method demonstrated high sensitivity with the limit of detection (LOD) ranging from 0.05 to 0.25 ng/mL, with exception of L-PFOS where the LOD was 1.46 ng/mL. For the biotic samples, the method detection limits (MDLs) were slightly higher than the LODs and ranged from 0.09 to 0.46 ng/g wet weight (w.w.) with exception of L-PFOS (MDL = 6.87 ng/g w.w.).
authors.affiliation: Wildlife and Landscape Science Directorate, Science and Technology Branch, Environment Canada, National Wildlife Research Centre, Carleton University, Ottawa, ON, K1A 0H3, Canada.
authors.forename: Shaogang
authors.initials: S
authors.lastname: Chu
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Letcher
mesh_terms: D017738:Alkanesulfonic Acids / Q000032:analysis* / Q000097:blood / Q000737:chemistry; D000818:Animals; D001717:Birds; D005260:Female; D005466:Fluorocarbons / Q000032:analysis* / Q000097:blood / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D007536:Isomerism; D008099:Liver / Q000737:chemistry; D008297:Male; D010063:Ovum / Q000737:chemistry; D000644:Quaternary Ammonium Compounds; D012680:Sensitivity and Specificity; D052616:Solid Phase Extraction / Q000379:methods*; D013552:Swine; D001503:Ursidae
chemical_list: D017738:Alkanesulfonic Acids; D005466:Fluorocarbons; D000644:Quaternary Ammonium Compounds; C076994:perfluorooctane sulfonic acid; C009405:tetrabutylammonium