Application of bovine serum albumin-decorated magnetic biochar for the extraction of per- and polyfluoroalkyl substances in food samples

A magnetic solid-phase extraction (MSPE) method with synthesized bovine serum albumin-decorated magnetic biochar (BSA/MBC) was developed for the extraction of per- and polyfluoroalkyl substances (PFAS) in food matrices. The combination of the specific affinity of proteins for PFAS and the hydrophobic surface of biochar allowed the material to adsorb a broad spectrum of PFAS without interference from complex matrices. The MSPE-ultrahigh-performance liquid chromatography-Orbitrap high resolution mass spectrometry method was applied to the analysis of 19 target PFAS with salt concentration of NaCl (6 %, w/v), pH of 5, 20 mg of BSA/MBC, 20 min of extraction time, 1 mL of methanol as the elution solvent and 1 min of elution time. The method showed excellent sensitivity with the good linearity in the range of 0.005–10 μg/L, and limits of detection and quantification of 0.001–0.027 μg/L and 0.005–0.091 μg/L, respectively. Furthermore, target PFAS were detected in real samples (i.e., bottled black iced tea, egg, cow’s milk and human milk) with recoveries ranging from 77.3 % to 127 %. In comparison with commercial SPE WAX cartridges, BSA/MBC demonstrated a higher affinity for sulfonamide PFAS.