Analysis of Ultrashort-Chain (C2, C3) and Alternative PFASs: LC-MS/MS Method Development and Application to Water Sample

Characterization of Polyfluoroalkyl Substances in the Environment
Poster Presentation

Prepared by , J. Steimling, S. Steinike, T. Kahler, M. Chang

Contact Information: shun-hsinliang@restek.com; 814-353-1300


ABSTRACT

LC-MS/MS methods for the analysis of legacy short-chain (C4, C5) and long-chain (>C5) per- and polyfluoroalkyl substances (PFASs) have been well-developed based on reversed-phase (RP) chromatography. It is necessary to pair with an additional delay column to isolate the interference generated from HPLC systems for low-level PFAS analysis especially when direct injection methodology is adopted without sample concentration procedure. With proper modification, these typical RP methods can be applied to the analysis of emerging PFAS alternatives such as GenX and ADONA, which are perfluoroalkyl ether carboxylic acids (PFECAs) used as PFOA substitutes. These established LC methods, however, may not be suitable for the analysis of newly trending ultrashort-chain (C2, C3) PFASs mainly due to their insufficient retention on typical RP columns.

While the use of short-chain PFASs (PFBA and PFBS) is intentional, more and more studies have shown the ubiquitous occurrence of C2 and C3 ultrashort-chain PFASs in aqueous environmental samples. These include trifluoroacetic acid (TFA), perfluoropropanoic acid (PFPrA), perfluoroethane sulfonate (PFEtS), and perfluoropropane sulfonate (PFPrS). It was shown that PFPrA is the predominant PFAS (up to 45% of total detectable PFASs) in the rain and snow samples collected from USA, France, and Japan. To date, there are not many studies showing the contamination sources and levels for these ultrashort-chain PFASs. A recent study showed the detection of PFEtS and PFPrS in aqueous film-forming foams (AFFFs) and ground waters from 11 military sites in the US, indicating AFFF firefighting foam may be one of the sources of the ultrashort-chain PFASs.

This presentation will discuss the LC-MS/MS method development for C2 and C3 PFASs analysis and analytical methodologies for simultaneous chromatographic determination of alternative and legacy PFASs.