6:2 Chlorinated polyfluoroalkyl ether sulfonate (Cl-6:2 PFESA, trade name: F-53B) is an alternative to perfluorooctanesulfonate (PFOS) products in electroplating. It was developed as a mist suppressant initially in the 1970s, but environmental occurrence, behaviors and potential adverse effects have only been noticed recently. Fate of Cl-PFESAs was also indistinct due to presence of chlorine atom and ether functional groups in the molecular structures. Here we focused our research on identification of PFESA analogues in municipal sewage sludge samples. Meanwhile, the transformation potential of Cl-6:2 PFESA was tested in an anaerobic super-reduced cyanocobalamin (CCA) assay. A suspect screening strategy using liquid chromatography-high resolution mass spectrometry (LC-HRMS) was taken. Accurate molecular ion [M(35Cl)]- and characteristic fragmentation ion [M(35Cl)-C2F4SO3]- of 6:2, 8:2 and 10:2 Cl-PFESA were discovered (△m &lt; 2.754 ppm), indicating presence of several analogues in the sludge extract. PFOS was the predominant contaminant with a geometric mean (GM) value of 3.19 ng/g, which was subsequently followed by 6:2 Cl-PFESA and 8:2 Cl-PFESA (GM: 2.15 and 0.50 ng/g, respectively). Transformation of Cl-6:2 PFESA was verified in the super-reduced CCA assay. Hydrogenated (1H-6:2 PFESA, 2H-6:2 PFESA) and unsaturated (6:2 PFUESA, 1H-6:2 PFUESA) products were identified by non-target screening strategies. During the transformation process, chlorine in Cl-6:2 PFESA molecular structure was firstly replaced by hydrogen with the formation of 1H-6:2 PFESA. HF reduction occurred afterwards, which generate the unsaturated 6:2 PFUESA. The transformation proceeded by hydrogen addition to form saturated 2H-6:2 PFESA. 1H-6:2 and 1H-8:2 PFESA were positively identified in sediment and sewage sludge samples collected from a region with metal-plating facilities. The GM concentrations were 4.4 pg/g for 1H-6:2 PFESA and 1.9 pg/g for 1H-8:2 PFESA.

Identification of novel chlorinated and hydrogenated polyfluoroalkyl ether sulfonates in sewage sludge by high-resolution mass spectrometry

2019 Spring National Meeting

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