DFT and MDS-assisted synthesis of functional core–shell COFs @ Fe3O4 @C nanoparticles for efficient extraction and detection of estrogens in food samples

Estrogen compounds in food exhibit bioaccumulation and endocrine-disrupting effects, posing serious risks to ecosystems and human health. Here, a novel core–shell magnetic covalent organic framework (COFs @ Fe 3 O 4 @C NPs) was developed for efficient enrichment and sensitive detection of estrogens in meat samples. The adsorption feasibility and mechanism of TAPB-DVA-COF were investigated using density functional theory (DFT) and molecular dynamics simulation (MDS). DFT calculations confirmed that hydrogen bonding and π–π stacking drive spontaneous adsorption, with adsorption energies ranging from −21.26 to −11.59 kcal mol −1 . MDS further revealed the formation of stable estrogen-COF complexes through close interfacial contact and persistent hydrogen bonding, confirming the existence of low-energy conformations. Based on these insights, COFs were anchored onto polydopamine-modified carbon-coated Fe 3 O 4 nanoparticles at room temperature to fabricate a magnetic adsorbent, which was then employed as a magnetic solid-phase extraction (MSPE) material. The adsorbent exhibited high surface area, strong magnetic responsiveness, and excellent stability. Coupled with high-performance liquid chromatography (HPLC), the established MSPE–HPLC method achieved a wide linear range ( R  ≥ 0.9996) and low detection limits (0.21–12.79 μg L −1 ). In pork and chicken samples, recoveries ranged from 91.7 % to 113.5 % with relative standard deviations of 1.0–6.1 %. This study demonstrates the superior performance of COFs @ Fe 3 O 4 @C NPs for estrogen detection and highlights MDS as an efficient and economical tool for predicting adsorption behavior, offering valuable guidance for material design.