The Preparation And Application Of Indole Acetic Acid And Hydroxy Benzoic Acid Molecularly Imprinted Polymers

In this thesis,indole 3-acetic acid?IAA?and p-hydroxybenzoic acid?p-HBA?molecularly imprinted polymers were synthesized,respectively,by precipitation polymerization method.Also 3,4-dihydroxybenzoic acid?PCA?magnetic molecularly imprinted polymer was prepared on the surface of Fe₃O₄@SiO₂ support by the surface molecular imprinting technique.The molecular recognition performances of the three kinds of molecularly imprinted polymers were characterized systematically including the isothermal adsorption curve,adsorption kinetics,adsorption selectivity,etc.At last,the optimum molecularly imprinted polymers were used in the pretreatment of food samples,and the separation and purification of the target compounds were realized with satisfactory.In the introduction section,the molecular imprinting technology,the preparation methods,characterization and applications of molecularly imprinted polymers were outlined.The research progresses on indole 3-acetic acid and hydroxybenzoic acids which were the target compounds under investigation were summarized.The future prospects for the molecular imprinting technique were also presented.In the experim-ental section,molecularly imprinted polymer particulates were prepared for three different templates.IAA-and p-HBA-molecularly imprinted polymer particulates were prepared by precipitation polymerization method using IAA or p-HBA as the template,acrylamide?AM?as the functional monomer,ethylene glycol methacrylate?EGDMA?as the crosslinking agent and azodiisobutyronitrile?AIBN?as the initiator in the solvent of acetonitrile.The adsorption and molecular recognition performances of the imprinted polymers were evaluated by high-performance liquid chromatography.The chemical and morphological features of the optimum imprinted polymers were characterized by means of Fourier transform infrared spectoscopy?FT-IR?and scanning electron microscopy?SEM?.The adsorption abilities of the imprinted polymers to the template molecule were further investigated through static adsorption and dynamic curve.The polymers prepared under the optimal conditions were used as the solid phase extraction adsorbents,and the solid phase extraction?SPE?were carried out to extract the target compounds in different real samples successfully.The results demonstrate that molecular imprinted polymer particulates specific for IAA or p-HBA have been obtained via precipitation polymerization method.The optimum IAA-imprinted polymer particulates were suitable as the solid phase extraction adsorbents for the separation and purification of IAA in the real samples such as mung bean sprout,rice and wheat,with high recovery rates and good reliability.In addition,the optimum p-HBA-imprinted polymer particulates were suitable as the solid phase extraction adsorbents for the separation and purification of p-HBA in the real samples of Gastrodia elata or PCA in grape juice.Magnetic molecularly imprinted polymers of PCA were prepared by surface imprinting technology,in which Fe₃O₄@SiO₂ grafted with KH570 was used as the magnetic support,PCA as the template,4-vinylpyridine as the functional monomer,EGDMA as the crosslinking agent,AIBN as the initiator,and acetonitrile as the solvent.The preparation conditions were optimized.The optimal polymer was characterized utilizing these methods such as FT-IR,SEM,thermogravimetric analysis and magnetic measurement methods.The adsorption properties of the magnetic imprinted polymer for the template molecule PCA was evaluated by both static adsorption and dynamic binding.The optimal magnetic imprinted polymer was examined to purify PCA in the sample of grape juice.The results indicated that magnetic PCA molecularly imprinted polymer?PCA-MMIPs?nanospheres with core-shell structure were successfully achieved,and PCA-MMIPs exhibited molecular recognition ability for PCA,with high adsorption capacity and fast binding.Under the applied magnetic field,the operation of the magnetic-SPE was easy to go.The polymer was suitable for the separation and purification of PCA in the real sample of grape juice.