Online extraction based on ionic covalent organic framework for sensitive determination of trace per- and polyfluorinated alkyl substances in seafoods by UHPLC-MS/MS

The ionic covalent organic framework (TPB-BFBIm-iCOF) was facilely synthetized by the size-controllable confinement method and chosen as the online solid phase extraction (SPE) adsorbent. This adsorbent showed fast adsorption equilibrium (5 min) and high adsorption capacity (87.7–140.8 mg g−1) for the per- and polyfluorinated alkyl substances (PFASs). The TPB-BFBIm-iCOF microsphere revealed the satisfactory enrichment performance for PFASs by means of the electrostatic interaction, hydrophobic effect and ordered channel structure. After extraction, the loaded TPB-BFBIm-iCOF-online SPE column was eluted and applied to the ultrahigh performance liquid chromatography tandem mass spectrometry analysis. Under the optimum conditions, the method displayed satisfactory linearity (R2 ≥ 0.9910) and low limits of detection (≤0.0017 ng g−1) for five seafoods. The relative recoveries of PFASs were 85.3%–109.4% with the relative standard deviation ≤ 9.9%. The method exhibited potential value in monitoring the toxicokinetics and environmental behaviors of PFASs.