Ternary Magnetic Fe 3 O 4 @C 3 N 4 @Covalent Organic Framework for Facile Extraction For Facile Extraction and Determination of Organophosphorus Pesticides in Fruit

Organophosphorus pesticides are widely used in agriculture and animal husbandry, which pollute the environment while endangering food safety. The aim of this study is to develop a smart adsorbent for the accurate enrichment and determination of trace organophosphorus pesticides, which is an important goal in the field of food safety. Herein, a covalent organic framework (COF)-based smart adsorbent, Fe3O4@C3N4 @COFs, was successfully fabricated via a versatile layer-by-layer assembly strategy and applied to simultaneous selective recognition, detection, and removal of profenofos. After seven regeneration cycles, the composite exhibited excellent selectivity and affinity for profenofos. Under optimized conditions, the proposed magnetic solid-phase extraction method coupled with high-performance liquid chromatography-tandem mass spectrometry showed good linearity ( R2 ≥ 0.9973) with a low limit of detection (0.5–200.0 μg/L) for profenofos. The developed method was successfully used to detect profenofos in spiked fruit samples with satisfactory recoveries (74.33%–116.59%) and relative standard deviations (0.27%–7.41%). This study highlights the potential of COF-based smart adsorbents in sample pretreatment for targeted analysis and is a novel pathway for efficient sample preparation in food safety analysis.