Isomeric separation of branched PFOS isomers : an application of C18 based stationary phases for liquid chromatographic separation

• Main Author: Berntzen, Mathias André Myhre
• Other Authors: Kallenborn, Roland Peter
• Format: Master Thesis
• Language: English
• Published: Norwegian University of Life Sciences, Ås 2022
• Subjects: Ny-Ålesund; Sogna; Ny Ålesund
• Online Access: https://hdl.handle.net/11250/3038438

Perfluorooctanesulfonate (PFOS) is a synthetic chemical that persist ubiquitously in waters and soils all over the world. PFOS has since its invention in the 1950 been one of the most produced per- and polyfluorinated alkylated substances (PFAS). The physical and chemical properties of PFOS is the reason it has been utilized in industrial sectors and household items as surfactants. The large area of applicability has consequently given multiple contamination sources. As a result of PFOS persistency in nature and links to multiple negative health effects, PFOS is classified as a persistent organic pollutant. A process called electrochemical fluorination (ECF) is the most common way to synthesize PFOS. This process synthesizes approximately 70% linear PFOS (L-PFOS) in addition to approximately 30% branched isomers of PFOS (Br-PFOS). The objective of this study was to develop and validate an analytical method for quantification and separation of L-PFOS and 7 Br-PFOS isomers found in the technical product of PFOS by ECF. The analytical method was developed on a high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) instrument with an ACE Excel C18- PentaFluoroPhenyl (PFP) column. The method will attempt to quantitate the PFOS isomers individually in freshwater samples from a river in Fjellhamar, a lake called Sogna in Kjeller and run-off water from Ny-Ålesund to create an isomer profile for each location. The sample locations have possibilities of PFOS contamination from Aqueous Film-Forming Foam which is a major contamination source. The method was validated and managed to separate the target isomers into 5 groups of PFOS, whereas 3 of them were single separated isomers, while the remaining 2 peaks consisted of coeluted isomers. Each group was treated as analytes and was applied to quantitate PFOS isomers in the water samples. Both L-PFOS and Br-PFOS were detected at all sites proving that each study site had PFOS contamination. Some of the analytes were not at a detectable or quantifiable ...