Per- and polyfluoroalkyl substances (PFAS) are highly valuable in various applications due to their exceptional physicochemical properties. However, they have also been associated with adverse effects on human health and the environment. Owing to their high chemical stability and ability to transition between water, soil, and the atmosphere, PFAS tend to persist and accumulate in the environment, posing significant risks to both humans and wildlife. Therefore, stringent regulation of these substances is essential, which necessitates the development of robust analytical methods for their detection.
In my diploma thesis, I optimized a solid-phase extraction (SPE) method for PFAS. The extracted analytes were subsequently analysed using an established LC-MS/MS method.
The extraction method was optimized by selecting a suitable SPE cartridge and elution solvent. I investigated the influence of pH and salt concentration in the sample solution on the extraction efficiency. Additionally, I determined the breakthrough volume of the method and identified the most appropriate solvent for LC-MS/MS analysis. The stability of PFAS stored in Milli-Q water under refrigerated conditions was also evaluated.
The results indicated that the Oasis WAX (Waters) SPE cartridge was the most suitable for PFAS extraction. The most effective elution solvent was found to be a 5% ammonia solution in methanol. Both pH and salt content significantly affected extraction efficiency. For seawater samples, optimal conditions were pH in the range of 2–3 and salt concentration of approximately 3,5%. The method demonstrated a breakthrough volume exceeding 500mL.
For LC-MS/MS analysis, Milli-Q water proved to be the most suitable solvent. Furthermore, it was confirmed that PFAS remain stable in refrigerated Milli-Q water for at least one month.
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