Analysis of hexafluoropropylene oxide-dimer acid (HFPO-DA) by liquid chromatography-mass spectrometry (LC-MS): Review of current approaches and environmental levels

Abstract

Emerging per-and polyfluorinated compounds (PFAS) compounds are of increasing interest for environmental monitoring, one being hexafluoropropylene oxide-dimer acid (HFPO-DA), commonly referred to as GenX. The following review describes existing liquid chromatographymass spectrometry (LC-MS) methods used to analyze HFPO-DA, including sample preparation and method sensitivity relative to other PFAS. Analytical challenges are also described, in particular the significant formation of in-source fragmentation, dimer and dimer adducts which detract from [M−H] − signal. Lastly, detected levels of HFPO-DA in environmental and biological samples are compared across the limited number of available field exposure studies, which found several μg/L concentrations in water samples taken near fluorochemical plant discharges.

Development and validation of an LC–MS/MS method for the quantitation of 30 legacy and emerging per- and polyfluoroalkyl substances (PFASs) in human plasma, including HFPO-DA, DONA, and cC6O4

“…Unlike other PFASs, HFPO-DA presented a peculiar fragmentation behaviour as an in-source fragmentation was observed, as previously described [78]. In order to increase sensitivity, the most intense fragment generated was chosen for both the native compound and its related isotopic labelled internal standard, despite the latter not matching the quant.…”

Development and validation of a high resolving power absolute quantitative per‐ and polyfluoroalkyl substances method incorporating Skyline data processing

“…This can, in turn, affect the reproducibility of these signals and must be monitored carefully. HFPO‐DA presented a unique challenge as it predominates as its decarboxylated form as a result of in‐source fragmentation 15 . For both the native and heavy isotope–labeled variants of this compound, the decarboxylated form was selected for MS1 peak integration.…”

Legacy and Emerging Per- and Polyfluoroalkyl Substances: Analytical Techniques, Environmental Fate, and Health Effects

“…There are, however, some analytical challenges for certain subclasses of emerging PFAS. One challenge associated with measuring HFPO-DA and other perfluoroethercarboxylic acids (PFECAs) is the fact that these compounds often exhibit poor LC-MS/MS sensitivity, which appears to be at least partially related to insource fragmentation during electrospray ionization (ESI) [24,34,35]. However, Brase and Spink recently reported significantly enhanced sensitivity for HFPO-DA and eight other PFECAs by making facile instrument modifications [36], demonstrating that these compounds can be easily incorporated into existing methods for PFAS determination.…”