Magnetic molecularly imprinted inverse opal photonic microspheres for high-performance enrichment and analysis of ochratoxin A in cereals

Ochratoxin A (OTA) is a mycotoxin and can threaten human health through the food chains. It is essential to develop an effective OTA analysis method to prevent the contaminated cereals from entering the food chain. Here, an analogue of OTA was selected as the template and 3-aminopropyltriethoxysilicane was used as the functional monomer, to prepare a magnetic molecularly imprinted nanoparticles, which were further mixed with polystyrene and SiO 2 nanoparticles to make magnetic molecularly imprinted inverse opal photonic crystal microspheres (MIP@MIPCMs) by a microfluidic self-assembly strategy. Infrared analysis, scanning electron microscope, transmission electron microscope, and metallographic microscopy techniques have been used to characterize MIP@MIPCMs and its control materials, demonstrating the expected MIP@MIPCMs were synthesized successfully. The imprinting factor of MIP@MIPCMs was tested to be 7.3, and its cross-reactivity factors range from 2.3 to 12.9, demonstrating it has good selectivity and specificity. Using MIP@MIPCMs as the sample pretreatment material to enrich OTA from cereals, the detection limit can reach to 0.48 ng/mL by integrating with HPLC analysis, and the spiked recoveries were 80–104 %, indicating the MIP@MIPCMs have a high-performance enrichment capability.