Functionalized magnetic covalent organic frameworks for extraction of bisphenols in food samples

Abstract

Bisphenols were recognized as a classical endocrine disrupting chemical threading public health. At present, the main limitation of removing bisphenols from food samples is the lack of specific functional or attribute covalent organic frameworks for strategic modification to improve the adsorption capacity of bisphenols. This work introduces fluorine groups and hydroxyl groups on magnetic covalent organic frameworks to improve the adsorption of bisphenols (Fe₃O₄@COF@F, and Fe₃O₄@COF@OH). It is worth noting that Fe₃O₄@COF@F exhibits excellent selectivity in the removal of bisphenols (adsorption capacity = 299.4 mg g⁻¹) compared with Fe₃O₄@COF@OH, displaying the important role of hydrogen bonding interactions, fluorinated shells and a more ordered porous structure. In addition, the extraction efficiency of Fe₃O₄@COF@F on bisphenols maintains almost unchanged after five cycles. Finally, the method of magnetic solid-phase extraction with high-performance liquid chromatography based on Fe₃O₄@COF@F was established for removing five bisphenols. Under optimized conditions, the limit of detection of bisphenols is 0.33 μg L⁻¹, with recoveries of 82.1–101.4 %. The proposed method was successfully applied for BPs (Bisphenol F, Bisphenol A, Bisphenol B, Tetrabromobisphenol A, and P-tert-butylphenol) removal in food samples.