A highly fluorinated functionalized magnetic covalent organic framework for high-efficient extraction of aflatoxins from diverse food matrices

Aflatoxins, carcinogenic mycotoxins, pose a global threat to food safety. Rapid, sensitivity and reliable quantitative detection of trace aflatoxins in diverse food matrices is critical for safeguarding public health but remains challenging. To address this, rational design of adsorbents with abundant specific binding sites offers a promising solution. Herein, a novel fluorine-rich magnetic covalent organic framework (4F-COF@Fe₃O₄) was facilely synthesized, featuring a high specific surface area (945.438 m² g^-1). Computational and experimental investigations confirmed that synergistic interactions and large specific surface area were key to its enhanced extraction performance. Utilizing only 2 mg of adsorbent, 4F-COF@Fe₃O₄ based magnetic solid phase extraction coupled with HPLC-MS/MS was developed for analysis of aflatoxins in nine types of food matrices. This method exhibited good linearity (0.010-50 μg kg^-1), low limits of detection (0.001-0.029 μg kg^-1), and satisfactory recovery (71.5-112.8 %). The results demonstrated the potential of 4F-COF@Fe₃O₄ as a superior adsorbent for trace aflatoxins monitoring.