Preparation of Zearalenone Metal Phenolic Network-coated Immunomagnetic Beads and Their Application in Pre-treatment of the Assay

The present study aimed to establish a pretreatment method for specific and rapid enrichment of zearalenone (ZEN) using metal-phenolic network (MPN)-modified immunomagnetic beads (IMBs) for efficient detection of ZEN in grains and feed. Surfaces of Fe3O4@SiO2-NH2 magnetic microspheres were coated with MPNs to enable directional immobilization of anti-ZEN antibodies via metal-phenolic hydroxyl coordination and hydrogen bonding. The results revealed that at pH5.5, 80 μg antibody immobilized per mg magnetic beads, and 10 min incubation duration, the IMBs had a saturated adsorption capacity of 35 ng/mg, with the Langmuir adsorption equilibrium constant KL of 595.1 L/mg. Spiked recovery tests performed in corn, wheat, and feed matrices, with recoveries >90% and coefficients of variation (CVs) within 1.3%~4.5% at spiking levels of 30~60 µg/kg. At the elevated spiking level of 120 µg/kg, consistent recoveries of 81.0%, 83.7%, and 77.6% were maintained with CVs≤6.5% across the three matrices. This method demonstrated excellent anti-interference performance towards interfering substances such as starch and pigments in complex substrates, including corn, wheat, and feed. When this method and the immunoaffinity column method were separately applied for sample pretreatment, the results showed a relative standard deviation of ≤7.30%, indicating good consistency between the two methods. By achieving synergy between specific recognition and controllable dissociation, our strategy provides a reliable solution for efficient ZEN enrichment in grains and feed.