Research On Preparation And Application Of4-Methylimidazole Magnetic Molecularly Imprinted Polymer

4-methylimidazole(4-MI)is a small molecular compound produced by the food industry in the production of caramel color.Studies have shown that 4-methylimidazole has the risk of causing convulsions and cancer.Because it is widely found in foods containing caramel color,it may harm human health.The World Health Organization(WHO)stipulates that the content of 4-methylimidazole in caramel color shall not be greater than 200 mg/kg,so it is necessary to establish an accurate and effective detection method for 4-methylimidazole.In this paper,the 4-methylimidazole magnetic molecularly imprinted polymer(MIP)was combined with High-performance liquid chromatography,and the preparation conditions were optimized by response surface methodology,with 4-methylimidazole as template molecule and methacrylic acid as functional monomer,ethylene glycol dimethacrylate(EGDMA)was used as crosslinker,acetonitrile as pore-forming agent,and functional monomer:Template Molecule(6.233:1,mmol/mmol),pore-forming agent 50m L,crosslinker:functional monomer(5.4:1,mmol/mmol),temperature 70°C were controlled,preparation of 4-methylimidazole molecularly imprinted polymers;In addition,4-methylimidazole magnetic molecularly imprinted polymers(MMIPs)and 4-methylimidazole magnetic non-molecularly imprinted polymers(MNIPs)were prepared by coating 4-methylimidazole magnetic nanoparticles(Fe₃O₄@Si O₂)on the surface of magnetic nanoparticles.The samples were characterized by electron microscopy?x-ray diffraction and fourier infrared spectroscopy.The adsorption kinetics test of MMIPs and MNIPs confirmed that the adsorption saturation time of MMIPs was about 40min.The adsorption thermodynamics tests of MMIPs and MNIPs determined the effect of the initial concentration of solution on the adsorption capacity of MMIPs.When the initial concentration of solution was 1.5mmol/L,MMIPs could reach the adsorption equilibrium at 40min,and the saturated adsorption capacity was 23.97mg/g.The selectivity of the prepared MMIPs to 4-methylimidazole was significantly higher than that of other structural analogs by selective adsorption test,and the MMIPs had specific recognition ability.And the MMIPS regeneration test proved that the regeneration performance is good.MMIPS combined with high performance liquid chromatography was used to detect the samples and the labeled recovery experiment.The results showed that the content of 4-methylimidazole in the samples was 0.054-1.099mg/L,the recovery rate was 83.47-96.89%,and the relative standard deviation was 0.38-2.78%,the detection limit is 10?g/L.This experiment realized the specific adsorption and rapid separation of 4-methylimidazole in food samples,which laid a foundation for the quantitative determination of 4-methylimidazole in food.