The Preparation And Application Of Vanillin Molecularly Imprinted Stirring Rod Based On Magnetic Field-induced Self-assembly

Nowadays,the safety of infant formula has a highlight of the world.Whereas many infant foods are mixed with various food additives,such as vanillin,in order to enhance milk flavor.These enhancers have been suspected of having adverse effects on liver and kidney functions in different degrees of the baby when large amounts of them are ingested from the infant formulas.Herein,the research to monitor the food additives in infant foods has an important significance.A molecular imprinting stir bar was constructed based on Fe₃O₄@Polyaniline nanoparticles with magnetic field-induced self-assembly process.The monomer,methacrylic acid,was pre-assembled into the pre-polymers with vanillin as template by the formation of hydrogen bonds.After that,the magnetic complexes were generated by the hydrogen bonding,the hydrophobic and?-?interaction between the pre-polymers and Fe₃O₄@Polyaniline.The complexes were adsorbed on the surface of magnetic stir bar under the magnetic induction,and the coating of vanillin-molecularly imprinted polymers was generated by the one-step copolymerization basing on the cross linking of ethylene glycol dimethacrylate.The molecular imprinting stir bar showed superior selectivity and fast binding kinetics for vanillin,and was used for the enrichment of vanilla-flavor enhancers?vanillin,ethyl maltol and methyl vanillin?in infant milk powders.The results measured by HPLC-UV exhibited good linear ranges of 0.01-10,0.02-10 and 0.03-10?g mL^-11 with the limit of detection of 2.5-10.0 ng mL^-1,and the recoveries were 94.7-98.9%,82.1-96.7%and 84.5-93.2%with RSD<7.2%for the three enhancers,respectively.