Study On Preparation And Properties Of Ginkgolides And Ordered Macroporous Quinine Molecularly Imprinted Materials

Cinchona alkaloids and ginkgolides have important applications in the clinical treatment and food industries.Cinchona and ginkgo trees remain the most economical source of these active ingredients.The development of highly selective adsorbents is of great significance for improving the separation efficiency of cinchona alkaloids and ginkgolides,reducing the cost of preparation,and increasing the utilization of natural products.Molecular imprinting technology is a technology for designing and synthesizing polymer materials that can specifically recognize and adsorb target molecules based on the structure of the target molecules.It is also an emerging technology currently used to separate and enrich natural medicinal ingredients.This paper aims to develop molecularly imprinted polymers(MIPs)with specific adsorption properties for cinchona alkaloids and ginkgolides.Aiming at the shortcomings of the low utilization of MIPs imprinted sites prepared by the bulk polymerization method,the pore structures were improved by preparing MIPs with a three-dimensional ordered macropore structure(3DOM)to improve the intra-particle mass transfer kinetics,thereby improving the utilization of molecularly imprinted sites and the adsorption capacity.The main contents of this paper are as follows:(1)Preparation of 3DOM quinine molecularly imprinted polymers and separation of cinchona alkaloids.First,three-dimensionally ordered macroporous thoil functionalized silica hybrids(3DOM SiO2-SH)were prepared by a colloidal crystal templating method.Then,3DOM MIPs were facilely prepared by grafting quinine-MIPs on the pore walls of the 3DOM SiO2-SH.The molecularly imprinted precursor solution were prepared by using quinine as a template,methacrylic acid as a functional monomer,ethylene glycol dimethacrylate as a crosslinking agent,and chloroform as a solvent.The materials were characterized by Raman,SEM,TGA and nitrogen adsorption measurements.The results showed that 3DOM MIPs had a more regular macroporous structure,a greater surface area and a greater porosity compared with the traditional bulk MIPs(TBMIPs).The 3DOM MIPs could reach a high MIPs content of 69.9%.And the 3DOM structure could improve the intra-particle adsorption and provide more accessible recognition sites.Consequently,in both static adsorption experiments and SPE,binding capacity of the 3DOM MIPs was higher than that of TBMIPs.Moreover,3DOM MIPs exhibited high affinity for quinine and quinidine.Using the quinine-3DOM MIPs as the SPE sorbent,quinine and quinidine could be effectively purified from the crude cinchona extract with high elution recoveries.(2)Preparation of Ginkgolide molecularly imprinted polymers and evaluation of their adsorption performances.High-purity mixed lactones were successfully separated from Ginkgo biloba extract by ultrasonic extraction,column chromatography,and recrystallization.The main components were ginkgolide A(GA)and ginkgolide B(GB).Then the mixed lactone was used as a template,acrylic acid(AA)and tetravinylpyridine(4-vp)were used as functional monomers,and ethylene glycol dimethacrylate(EDMA)and,glyceryl dimethacrylate(GDMA)and trimethylolpropane triacrylate(TMPTA)were used as cross-linking agents.The effects of the types and ratios of functional monomers and cross-linking agents on the adsorption properties of the prepared MIPs were investigated.The results showed that MIPs prepared with 4-vp as the functional monomer had higher adsorption capacity,KP and I values than MIPs prepared with acrylic acid as the functional monomer.MIPs prepared with 4-vp as the functional monomer and GDMA as the cross-linking agent have good affinity and selectivity for GB.MIPs prepared with 4-vp as the functional monomer and TMPTA as the cross-linking agent had good affinity and selectivity for both GA and GB.This thesis provide a new method to improve the pore structures of molecularly imprinted polymers and improve the utilization of imprinted sites.It also provides basic experimental data for the preparation of quinine and ginkgolide MIPs to achieve targeted separation of cinchona alkaloids and ginkgolide.Therefore,this thesis has good scientific significance and practical application value.