Automated and fast online method for simultaneously determining a broad spectrum of per- and polyfluoroalkyl substances in a small volume of cerebrospinal fluid.

Abstract

Per- and polyfluoroalkyl substances (PFASs) are potentially neurotoxic compounds. Levels of PFASs in cerebrospinal fluid (CSF) could directly reflect their potential harm to the central nervous system. Because of the variety of PFASs and the rarity of CSF, there is an urgent need to establish a rapid online method to detect a broad spectrum of PFASs accurately and simultaneously by consuming a small amount of CSF. In this study, we developed a fast and automated method to analyze 52 PFASs in human CSF samples using online TurboFlow ultra-high-performance liquid chromatography-tandem mass spectrometry. Our method offered excellent matrix-matched standard curve linearity (correlation coefficient > 0.99), good limits of quantitation (MLOQs) (0.01 to 0.08 ng mL-1), satisfactory accuracy (recoveries of 74.6%-119.1%) and precision (relative standard deviations of 1.4%-13.2%), small sample amount consumption (50 μL), and fast analysis time (18 min per sample) without complex sample pretreatment procedures. These are advantageous for the high throughput screening of PFASs in environmental epidemiology studies. Repeated freeze-thaw experiments showed that it was better to perform the analytical process soon as possible after sample collection. The established method was used to analyze PFASs in 60 people. Short-chain PFASs, perfluorobutanoic acid (PFBA), perfluoropentanoic acid (PFPeA), and novel PFASs [sodium 2-(N-ethylperfluorooctane-1-sulfonamido)ethyl phosphate (SAmPAP), perfluoroethylcyclohexanesulfonate (PFECHS), and perfluoro-3, 7-dimethyloctanoic acid (P37DMOA)] were reported in CSF for the first time. PFBA and PFPeA were detected in all samples with mean concentrations of 0.24 and 0.22 ng mL-1, respectively. We also calculated the blood-brain barrier transmission efficiency of PFASs (RPFAS), and the mean RPFBA value was above 1, which indicated that PFBA might transfer from serum to CSF.