Sensitive detection of pyrethroid pesticides in vegetables using COF-functionalized magnetic nanocomposites:...

In this work, covalent organic framework (COF)-derived magnetic nanocomposites (Fe₃O₄@PDA@COF_TABP), comprising Fe₃O₄ as the magnetic core, polydopamine (PDA) as the hydrophilic interlayer, and COF_TABP as the outer shell, were first constructed and utilized as the powerful adsorbents for the magnetic solid-phase extraction (MSPE) of pyrethroids (PYRs). The introduction of the PDA coating facilitated the growth of the COF_TABP shell and simultaneously provided additional adsorption sites, thereby enhancing the extraction efficiency. Molecular docking simulations revealed that Fe₃O₄@PDA@COF_TABP exhibited excellent affinity toward PYRs through synergistic π-π stacking, hydrogen bonding, and hydrophobic interactions. The developed MSPE method coupled with GC-μECD exhibited excellent linearity (R² ≥ 0.9988), low limits of detection (0.025-0.064 μg kg^-1), satisfactory recoveries (82.4 %-106.8 %), and low relative standard deviations (RSDs <7.1 %). Finally, the established method was successfully applied to the quantification of trace PYRs in vegetable samples, demonstrating its strong potential for routine pesticide residue monitoring in vegetables.