Rapid biomonitoring of perfluoroalkyl substance exposures in serum by multisegment injection‐nonaqueous capillary electrophoresis‐tandem mass spectrometry

Perfluoroalkyl substances (PFASs) are a major contaminant class due to their ubiquitous prevalence, persistence, and putative endocrine disrupting activity that may contribute to chronic disease risk notably with exposures early in life. Herein, multisegment injection-nonaqueous capillary electrophoresis-tandem mass spectrometry (MSI-NACE-MS/MS) is introduced as a high throughput approach for PFAS screening in serum samples following a simple methyl-tert-butyl ether (MTBE) liquid extraction. Separation and ionization conditions were optimized to quantify low nanomolar concentration levels of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) from serum extracts when using multiple reaction monitoring under negative ion mode conditions. Multiplexed separations of PFOA and PFOS were achieved with excellent throughput (<3 min/sample), adequate concentration sensitivity (LOD ∼ 20 nM, S/N = 3) and good technical precision over three consecutive days of analysis (mean CV = 9.1%, n = 84). Accurate quantification of PFASs was demonstrated in maternal serum samples (n = 16) when using MSI-CE-MS/MS following pre-column sample enrichment with median concentrations of 3.46 nM (0.7-9.0 nM) and 3.29 nM (1.5-6.6 nM) for PFOA and PFOS, respectively. This was lower than average PFAS exposures measured in pregnant women who had serum collected prior to 2009 likely due to subsequent phase out of their production. Overall, this method offers a convenient approach for large-scale biomonitoring of environmental exposures to legacy PFASs and their emerging replacements that is relevant to maternal health and chronic disease risk assessment in children.