Study On Preparation Of Ginkgolide B And Ordered Macroporous Quercetin Molecularly Imprinted Polymers And Their Separation Performances

Natural products are complex and low in content,thus developing novel separation materials with excellent adsorption selectivity and affinity is still a crucial issue to exploit natural products.Molecularly imprinted polymers(MIPs)are synthetic receptors with specific recognition sites that are complementary to a template molecule in terms of its shape,size and functionality.Therefore,MIPs show higher selectivity and affinity in rebinding the template than other molecules.So they have a promising application prospect in the field of enrichment and separation of medicinal ingredients of TCM.Ginkgolide B and quercetin separated from plants are the medicines with strong physio logical activity.In this paper,the molecularly imprinted polymer materials were studied and prepared for the separation of ginkgolide B and quercetin.Aiming at the shortcomings of the poor mass transfer effect of quercetin MIPs in the present bulk polymers,the quercetin MIPs with three-dimensional ordered macroporous structure was developed by combining with the colloidal crystal templating technology.The specific contents are as follows:Monodisperse silica beads were produced by using a modified Stober procedure.Silica colloidal crystal was obtained by centrifugating silica beads,then drying at room temperature and calcining at 800 ℃ for 5 h.Scanning electron microscopy measurements show that silica colloidal crystal have a highly ordered and face-centered cubic(fcc)structure.Ordered macroporous molecularly imprinted polymers(OMMIPs)were prepared by a combination of the colloidal crystal templating method and the molecular imprinting technique by using SiO2 colloidal crystal as the macroporogen,quercetin as the imprinting template,acrylamide as the functional monomer,ethylene glycol dimethacrylate as the cross-linker and tetrahydrofuran as the solvent,respectively.Scanning electron microscopy and Brunauer-Emmett-Teller measurements show that the OMMIPs have a more regular macroporous structure,a narrower pore distribution and a greater porosity compared with the traditional bulk molecularly imprinted polymers(TBMIPs).The kinetic and isothermal adsorption behaviors of the polymers were investigated.The maximum adsorption capacity of the OMMIPs is 636.9μg g-1,it is greater than that for TBMIPs with 526.3μg g-1.The intra-particle adsorption rate coefficient of the OMMIPs is 6.09μg g-1 min-0.5,which is greater than that for TBMIPs with 0.67μ g-1 min-0.5.The study of chromatographic behavior shows that OMMIPs have a better separation performance than TBMIPs.Ginkgolide B bulk molecularly imprinted polymers were prepared by using ginkgolide B as the imprinting template,acryclic acid as the functional monomer,trimethylolpropane triacrylate as the cross-linker and CH2Cl2-DMSO as the solvent.The kinetic and isothermal adsoiption behaviors of the polymers were studied.The results show that the MIPs have a higher adsorption capacity than the NIPs.The result of the specific selectivity study show that MIPs show a good specific selectivity for ginkgol lide B and the imprinting factor value is 2.33 that is greater than its structural analogues.This paper had developed simple and feasible synthetic strategies for the preparation of ginkgolide B MIPs and quercetin OMMIPs with the high separation efficiency,and provided new materials for separating ginkgo lide B and quercetin.Thus it had good scientific and practical value.