Date of Award

Spring 2026

Document Type

Open Access Thesis

Department

Chemistry and Biochemistry

First Advisor

Susan D. Richardson

Abstract

Per- and polyfluoroalkyl substances (PFAS) are ubiquitous in surface waters, yet conventional targeted liquid chromatography–tandem mass spectrometry (LC-MS/MS) captures only a limited number of compounds for which reference standards exist. As a result, a substantial portion of organic fluorine content remains uncharacterized. Total organic fluorine (TOF) methods, measured as extractable organic fluorine (EOF) or adsorbable organic fluorine (AOF) by combustion ion chromatography, offer a bulk measure of organic fluorine, but other compounds besides PFAS, such as fluorinated pharmaceuticals and pesticides, can also contribute to this TOF measurement. Therefore, it is not known how much of the TOF is really attributable to PFAS. Our work seeks to answer this question by developing and optimizing an integrated workflow for organofluorine analysis in surface water. A method to quantify 46 PFAS compounds (including long-chain, short-chain, and ultrashort-chain), 21 popular fluorinated pharmaceuticals, and 19 popular fluorinated pesticides using a combination of LC-MS/MS and gas chromatography–tandem mass spectrometry (GC-MS/MS) was developed and optimized. Solid-phase extraction (SPE) procedures were refined to balance recoveries across diverse analytes, with most exceeding 70%. Concentrations are converted to fluorine equivalents to enable direct comparison with AOF measurements. This framework provides a consistent basis for evaluating the relative contributions of different chemical classes to TOF. These efforts will improve the interpretation of TOF as an indicator of  PFAS contamination and advance the understanding of the broader fluorine burden in aquatic systems.

Rights

© 2026, Haritha Lawan Padikara Lekam Muhandiram Jayasinghege

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