Contamination of soils and water by per- and polyfluoralkyl substances (PFAS) is a pressing problem. Accurate analysis of PFAS including perfluoaroalkyl acid (PFAA) and heptadecafluorooctane sulfonic acid (PFOS) is recognized as a challenging task. The state-of-the art measurements of PFAS resort to LC-MS for detection. We show that time-of-flight secondary ion mass spectrometry (ToF-SIMS) can be used in sensitive analysis of PFAS. Several representative PFOS and PFAA chemicals such as PFBA, PFHpA, PFNA, PFOS, and PFPeA were analyzed using ToF-SIMS. Sample preparation was straightforward. Aqueous samples were directly deposited on a clean Si wafer and dried in air before ToF-SIMS analysis. Reagents in the powder form were dispensed in DI water before being deposited onto clean Si wafer. Molecular pseudo ions were easily discernable in the SIMS spectra. Principal component analysis (PCA) further demonstrates that each sample has specific spectral signatures. Our results prove that ToF-SIMS is capable of sensitive detection of PFOS and several PFAAs and can be a viable technique in PFAS analysis in the future.

Detection of PFOA by sensitive ToF-SIMS

2019 Fall National Meeting

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