An UHPLC-MS/MS Quantitative Method for Trace Analysis of Per- and Polyfluoroalkyl Substances (PFASs) in Environmental Media from Alabama Estuaries
Type of DegreeMaster's Thesis
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Per- and polyfluoroalkyl substances (PFASs) comprise a large group of anthropogenic industrial compounds that are highly persistent due to their chemical structure. Because of the wide use of PFASs in textile manufacturing, surfactant applications, coatings, and aqueous film–forming foams (AFFF) since the 1950s, some PFASs are ubiquitous in the environment and often found in environmental matrices. Analytical studies of PFASs are challenging due to the sophisticated analytical systems required to perform these studies, the lack of quantitative, validated analytical methods, and the limited availability of standards for quantitation of some PFASs. Standards for the quantitation of legacy PFASs are widely available, thus legacy PFASs are well studied. Emerging PFASs, however, remain understudied due to limited standard availability. The aim of this study was to develop a UHPLC-MS/MS analytical method to quantitate a selection of both legacy and emerging PFASs in a single experimental run. After chromatographic conditions were optimized, full scan, single ion monitoring (SIM) scan, product ion (PI) scan, and multiple reaction monitoring (MRM) scan were conducted to optimize MS conditions. The developed and optimized method is amenable to analysis of 23 target analytes including 13 perfluoroalkyl carboxylic acids (PFCAs), 8 perfluoroalkane sulfonates (PFSAs), and 2 perfluoropolyethers (PFPEs). The method demonstrated acceptable mean percent recoveries of 90.46% ± 4.09% and 103.94% ± 3.49% at two spiking levels (2 ng/L and 10 ng/L) of standard mixtures. Slight carry over issues were observed but can be avoided in future work. A sample extraction and cleanup strategy was designed and optimized using Oasis PRiME HLB 6cc extraction cartridges during sample purification. The developed quantitative method was applied to surface water samples collected from the Perdido Bay estuary. Eight out of twenty-three compounds were detected, with average total PFAS concentrations of 12.75 ng/L and 12.84 ng/L in July 2017 and October 2017, respectively.