Molecularly Imprinted Polymers For Solid-phase Extraction Of Oleanolic Acid In Privet Leaves

Abstract:Privet leaves are dried leaves of privet. Because of its detoxification, action of expelling scattered blood, swelling and pain and other effects, it has development prospect as a kind of wild medicinal plant resources. Its composition is very complex, containing oleanolic acid, ursolic acid.In this paper, privet leaves are studied, using ultrasound-enzymatic extraction technology to extract the active ingredient oleanolic acid from privet leaves. And molecularly imprinted solid phase extraction method is used to extract privet leaves selectively. Details are as follows:In this paper, oleanolic acid as template, azobenzene derivatives (homemade) grafted on10μm silica sphere as monomer, with surface imprinting technology, oleanolic acid molecularly imprinted polymer-silica microspheres are prepared through graft polymerization. In order to study the structure of the microspheres, infrared spectrum and scanning electron microscopy are done.As the molecularly imprinted microspheres contain azobenzene structure, which can response to light, they can effectively release template molecule oleanolic acid under365nm UV irradiation, resulting in better elution. Thus they have higher adsorption capacity and become a kind of ideal solid-phase extraction materials.In order to study the adsorption properties of the microspheres, dynamic adsorption kinetics experiment was made. Meanwhile, in order to study the selectivity of the molecularly imprinted polymer microspheres, they were filled as molecularly imprinted solid phase extraction material and successfully applied to the mixture of oleanolic acid and its analogs ursolic acid and privet leaves. When applied to actual samples privet leaves, the molecularly imprinted microspheres possess good separation and enrichment capabilities.