Synthesis And Molecular Recognition Of Flavonoids Functional Factors Of Traditional Chinese Medicines-imprinted Polymer

Molecular Imprinting Technology(MIT) is a novel technique for producing polymer materials with strong affinity and high selectivity for target compound(template).Those polymer materials are named Molecularly Imprinted Polymers(MIPs).MIPs are synthesized with a specific target compound as a template,so their space structures and function positions have highly tallied with template molecule.As a result,it has acquired an ability of memory recognition of template molecules and their structural analogs,which has a high selectivity and specificity.For its specific nature,MIPs are widely used in the separation,analysis,catalysis,sensors and other fields,and has a great development prospect in the future.Traditional Chinese Medicine(TCM) system is a complex system of natural combinatorial chemistry libraries,and the quality of TCM depends on the separation / extraction of various functional factors from Traditional Chinese herbal to a large extent.Thus,it is of important application values and practical significance to research the selective separation and extraction of effective functional factors from complex TCM system.This thesis firstly gives a brief overview of the basic principles of MIT,the preparation and application of MIPs,and offers an insight into current problems and future development trends of MIT.Secondly,two kinds of flavonoids functional factors of TCM-apigenin (API) and luteolin(LUT) were used as templates,respectively. And corresponding molecularly imprinted polymers were successfully prepared by bulk polymerization and characterized by FT-IR,UV-vis, thermogravimetric analysis(TG-DSC),scanning electron microscopy (SEM) and specific surface area and porous analysis apparatus.The presence of non-covalent interactions between template and monomer was verified by UV-vis spectrometric detection.The influence of different synthetic conditions(porogen,functional monomer, template-functional monomer ratio,crosslinker,polymerization temperature,etc.) on recognition properties of MIPs was investigated,in order to optimize the synthetic conditions of MIPs.Finally,the adsorption ability and molecularly selectivity of MIPs were evaluated by static equilibrium adsorption experiments.Moreover, the imprinting,recognition,mass transfer and adsorption mechanism of MIPs were discussed.The effect of the two imprinted polymers on the separation / preconcentration of API and LUT from Chrysanthemum morifolium Ramat crude is evaluated by high performance liquid chromatography(HPLC).The main findings gained are as follows: 1.A series of apigenin molecularly imprinted polymers(API-MIP) were synthesized with Apigenin as template by bulk polymerization and characterized.The best synthesis conditions are as follows: tetrahydrofuran(THF) as porogen,2-vinylpyridine(2-Vpy) as functional monomer,ethylene glycol dimethyl acrylate(EDMA) as crosslinker, n_(API):n_(2-Vpy):n_(EDMA)= 1:8:40,and polymerization temperature of 60℃.2.A series of luteolin molecularly imprinted polymers(LUT-MIP) were synthesized with luteolin as template by bulk polymerization and characterized,too.The optimum synthesis conditions of LUT-MIP are as follows:The mixture solution of tetrahydrofuran and chloroform (THF/CHCl₃,v/v = 8:2) as porogen,2-Vpy as functional monomer, EDMA as cross-linker,n_(LUT):n_(2-Vpy):n_(EDMA) = 1:10:50,and polymerization temperature of 60℃.3.The results indicated that the API-MIP exhibited a good adsorption affinity and an excellent selectivity toward the template molecule API,and its adsorption curve is in line with the Langmuir isotherm.Scatchard analysis revealed that two classes of binding sites were formed in the API-MIR The dissociation constants of high affinity binding sites(K_d1) and saturation binding sites(Q_max1) were estimated to be 99.01μg/mL and 1165.05μg/g,respectively.K_d2 and Q_max2 of low affinity binding sites were 2000.00μg/mL and 21274.67μg/g, respectively.Adsorption kinetics study showed that API-MIP adsorbed quickly in the first 45 minutes,and reached saturation adsorption quickly at 2h.4.LUT-MIP has a good adsorption affinity and selectivity for the template molecule LUT,its adsorption curve is in line with the Langmuir isotherm.Scatchard analysis revealed that two classes of binding sites were formed in the LUT-MIR The dissociation constants of high affinity binding sites(K_d1)and saturation binding sites(Q_max1) were estimated to be 312.50μg/mL and 1796.09μg/g,respectively.The values of the low affinity binding sites -- K_d2 and Q_max2 were 1111.11μg/mL and 4768.77μg/g,respectively.Adsorption kinetics study showed that LUT-MIP adsorbed quickly in the first 30 minutes,and reached saturation adsorption quickly at 1 h.5.The results of TG-DSC,SEM,specific surface area and porous analysis showed that API-MIP and LUT-MIP are porous polymers with thermal stability.Regeneration experiment proved that two kinds of molecularly imprinted polymers can be reused.6.The result of separation / preconcentration experiment showed that both of API-MIP and LUT-MIP had obvious effects to separate / preconcentrate API and LUT from Chrysanthemum morifolium Ramat crude,which was evaluated by HPLC.