Host-guest mediated recognition and rapid extraction of Fusarium mycotoxins in cereals by nickel ferrite magnetic calix[4]arene-derived covalent organic framework fabricated in room-temperature

Fusarium mycotoxins are toxic secondary fungal metabolites and widely distributed in cereals. Herein, a nickel ferrite magnetic calix[4]arene-derived covalent organic framework (NiFe 2 O 4 @CX4-COF) was meticulously designed and synthesized using a room-temperature method for the enrichment of mycotoxins. The CX4-COF exhibited a porous crystalline network with an eclipsed AA-stacking configuration. The ingenious integration of NiFe 2 O 4 , supramolecular calix[4]arene and COF contributed to host-guest mediated recognition, size-selectivity and high adsorption capacity, rapidly reaching adsorption equilibrium within only 3 min. Simulation calculations revealed that the host-guest interaction, size effect and abundant binding sites facilitated synergistically recognize and capture mycotoxins. NiFe 2 O 4 @CX4-COF has successfully applied for simultaneous extraction and analysis of mycotoxins in cereals, achieving negligible matrix effects (−14% to 13%), high sensitivity (LODs of 0.003–0.014 μg/L) and satisfactory recoveries (74.4%–116%). This work provides a prospective platform for constructing tailored macrocycle-based COFs under mild conditions for precise recognition and accurate analysis of trace hazardous substances in food.