Sensitive detection of pyrethroid pesticides in vegetables using COF-functionalized magnetic nanocomposites: Enrichment, mechanism, and quantification

In this work, covalent organic framework (COF)-derived magnetic nanocomposites (Fe 3 O 4 @PDA@COF TABP ), comprising Fe 3 O 4 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 Fe 3 O 4 @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 (R 2  ≥ 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.