Construction of functionalized covalent organic framework for the efficient enrichment of neonicotinoid insecticides...

Trace residues of neonicotinoid insecticides (NIs) in food may pose great risk to human health. In this study, an amino and triazine co-functionalized covalent organic framework (Tp@tr-COF) was fabricated and it exhibited enhanced adsorption performance for NIs compared with that of un-functionalized counterpart. The mechanism investigation revealed that hydrogen bond interactions and π-π stacking were the main adsorption forces. With Tp@tr-COF as solid phase extraction adsorbent, a sensitive high-performance liquid chromatography-mass spectrometry method was established for the determination of NIs in leafy vegetables. The accuracy and precision of the established method were verified, achieving low limits of detection (0.18-0.60 ng·g^-1) and satisfactory recoveries (88.0%-110%) with RSD ≤ 7.7%. Furthermore, the extraction recovery of Tp@tr-COF remained unchanged after 30 regeneration cycles. These data suggest that the proposed method is a promising alternative for quantifying NIs in leafy vegetables, while this study sheds light on the rational design of functionalized COFs.