Molecularly Imprinted Magnetic Chitosan Microsphere Method For Separating Tea Polyphenol Monomer EGCG

The purpose of this study is to prepare a material that separates tea polyphenols monomeric epigallocatechin gallate?EGCG?.the methods is that using EGCG molecularly imprinted on the surface of magnetic chitosan microspheres?MCMs?,then its characterization and detection of its adsorption properties.Which provides a new idea for the separation of EGCG from tea polyphenols.The study is divided into three areas:Firstly,EGCG-molecularly Imprinted Magnetic Chitosan Microspheres?E-MIMCMs?,which have magnetic properties and are selective for EGCG,are prepared.Using Fe₃O₄ and2%of chitosan solution as material,the chitosan was wrapped around Fe₃O₄ and formed into a MCMs after the emulsifier and crosslinking agent.MCMs were used as carrier and E-MIMCMs were prepared by suspension polymerization.In addition,the non-imprinted magnetic chitosan Microspheres?N-IMCMs?were synthesized and compared with E-MIMCMs.Secondly,the characterization of EGCG-molecularly imprinted magnetic chitosan microspheres.Using scanning electron microscopy?SEM?and Fourier infrared for the preparation of magnetic core,magnetic chitosan microspheres,molecularly imprinted materials characterization.The SEM results show that the magnetic imprinting material is spherical,the particle size distribution is in the range of 50?m to 300?m and molecularly imprinted materials surface drape,beneficial to the choice of EGCG.FTIR results show that chitosan and Fe₃O₄ were combined,and the characteristic absorption peak of EGDMA in the imprinted material indicates that it has successfully grafted to the surface of magnetic chitosan microspheres,The spectrum is basically the same as that of magnetic chitosan microspheres,indicating that EGCG elutes from the surface of magnetic chitosan microspheres.Finally,the adsorption properties of E-MIMCMs were examined.The adsorption conditions were optimized by single factor experiment and response surface experiment.The adsorption performance was investigated by static adsorption test,kinetic test,selective test and reusability.Results showed that the best adsorption conditions is that the add of E-MIMCMs is 19.11 mg,the rotation speed was 130 rpm,the adsorption temperature was30?,the initial concentration of EGCG was 300 mg/L,the adsorption time was 4 h,and the E-MIMCMs adsorption quantity is 69.44 mg/g.The static equilibrium adsorption test to get the maximum balance the adsorption capacity of E-MIMCMs was 69.14 mg/g,is 1.27 times higher than the N-IMCMs adsorption under the same conditions,which was consistent with the Langmuir isothermal adsorption adsorption model.The kinetic experiments showed that the imprinted and non-imprinted materials reached the adsorption equilibrium within 3 h,which accorded with the quasi-first order kinetic model.ECG and quercetin as the competition for EGCG,E-MIMCMs were more selective for EGCG.The adsorption of the imprinted and non imprinted material was 80.45%and 92.38%of the maximum adsorption of EGCG after five repetitions,which showed its good repeatability.