Simultaneous determination of multiple perfluoroalkyl and polyfluoroalkyl substances in aquatic products by ultra-performance liquid chromatography-tandem mass spectrometry with automated solid-phase extraction

Diet is an important route of human exposure to perfluoroalkyl and polyfluoroalkyl substances (PFASs), and aquatic products are the main dietary source of PFASs. This study aimed to establish a method for the analysis of 52 PFASs in typical aquatic products, such as crucian carp, large yellow croaker, shrimp, and clam, by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) after automated solid phase extraction (SPE). After optimization of the conditions of SPE, the recovery and precision of the method is within an acceptable range. The intra-day and inter-day average recoveries of spiked samples ranged from 66.5% to 122.3% and 64.5%-128.0% for crucian carp, large yellow croaker, shrimp, and clam, with intra-day and inter-day relative standard deviation (RSD) of 0.78%-11.4%, and 2.54%-24.2%. The ranges of method detection limits (MDLs) and quantification limits (MQLs) of PFASs were 0.003–0.60 ng/g and 0.005–2.0 ng/g, respectively. The accuracy of the method was also verified by standard reference material (SRM), and the measured values of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) were in the allowable range. The method was applied to analyze aquatic products from the local supermarket. The concentrations of ∑PFASs ranged from 13.9 ng/g ww to 75.5 ng/g ww. PFOS was the dominant pollutant, accounting for 79.6% of ∑PFASs. The branch-chain isomers, perfluoro-3-methylheptane sulfonate (P3MHpS) and perfluoro-6-methylheptane sulfonate (P6MHpS) accounted for one-quarter of PFOS. Long-chain perfluoro carboxylic acids (PFCAs) were also detected in most samples. The estimated daily intake of PFOS was over the recommended tolerable intake by several organizations such as the Minnesota Department of Health (MDH), the New Jersey Drinking Water Quality Institute (NJDWQI), and the European Food Safety Authority (EFSA). PFOS would have posed health risks to consumers through dietary exposure.