Abstract

Perfluoroalkyl substances, also known as PFAS, include thousands of compounds. These compounds have fluorinated carbon chain lengths as well as different functional groups. They have been found in the air, water, humans, animals, food, polar ice sheets, and soil. However, not much is known about them, especially when it comes to the conditions under which they undergo transport in the environment. Studies have shown that they are transported through cloud water and aerosol particles through partitioning, and they partition favorably into particles and water when the compounds are charged. This means that knowing the pKa values of PFAS will allow people to understand under what environmental conditions they undergo transport through aerosol particles and cloud water. This study focuses on creating a method to determine pKa values of PFAS.

To accomplish this, the water solubility of perfluorooctanoic acid (PFOA) and perfluorononanoic acid (PFNA) under a range of pH values at room temperature was found and analyzed using liquid chromatography with triple quadrupole mass spectrometry. A proton balance equation was used to determine the pKa values. The water solubility for PFOA was found to be 1.99×104 ng/mL and for PFNA 8.18×105 ng/mL. For PFOA, the water solubility experimental value is 100 times higher than the literature value and for PFNA, the experimental value is 10 times higher than the literature value. The pKa value for PFOA also does not match with the literature value. However, a method to determine the pKa was successfully developed.

Advisor

Faust, Jennifer

Department

Chemistry

Disciplines

Analytical Chemistry | Chemistry | Environmental Chemistry | Physical Sciences and Mathematics

Keywords

PFAS, pKa, buffers

Publication Date

2024

Degree Granted

Bachelor of Arts

Document Type

Senior Independent Study Thesis

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Available for download on Tuesday, January 01, 2075

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