Preparation And Separation Selective Law Research Of Molecularly Impirnted Polymers Of Compounds With Important Medical Value

Molecular imprinting is a technique for producing highly selective polymers which canrecognize a particular molecule. It is a new field which originates from multiple disciplinessuch as macromolecule science, material science, biology and chemical engineering. It is usedextensively in many fields, such as chiral resolution, biosensors, enzyme catalysis simulation,membrane separation techniques etc. With the successful application of molecularly imprintedpolymers （MIPs） in separation and purification, researchers have focused their main attentionon the separation direction of high value-added active ingredients from complicated samples.In this work, two kinds of medicine compounds Quercetin and Glutathione were used astemplate molecules, solution polymerization was selected as polymerization process, andQuercetin and Glutathione MIPs were prepared respectively. Thereafter, Quercetin MIP wasselected as carrier, four flavonoids that have the partial molecule structure similarity withQuercetin were chose, and Gaussian03and Chemoffice2006software were applied tocalculate molecular size, molecular volume and molecular polarity of template molecule andtarget molecules. The relationship between the molecule structure factors and adsorptionselectivity law of MIP was investigated preliminary. The research contents and results indetails were as follows:1. Quercetin MIP was prepared using N-vinylpyrrolidone and acrylic acid as functionalmonomers, and N, N’-methylenebiacrylamide as crosslinker in an ethanol and water mediumby solution polymerization. The adsorption capacity and separation degree of MIP toQuercetin from the mixture of Quercetin and Genistein was an objective, and the effects of themonomers, crosslinker and initiators on adsorption selectivity and the process conditions wereoptimized. The optimum conditions obtained were molar ratios of Quercetin, acrylic acid, N,N’-methylenebiacrylamide and hydrogen peroxide to N-vinylpyrrolidone were0.0714,3,2.5and0.00881, and the polymerization temperature and time were35oC and20h, respectively.MIP prepared at the optimum conditions presented favourable adsorption of Quercetin with amaximum separation degree of6.58. Scatchard analysis revealed that heterogeneous bindingsites were formed in MIP.2. MIP for Glutathione was prepared using N-vinylpyrrolidone and acrylamide asfunctional monomers, N, N’-methylenebiacrylamide as crosslinker, H₂O₂-Vc as initiator, andmethanol and water as medium. The adsorption capacity and separation degree of MIP toGlutathione from the mixture of Glutathione and L-homocysteine was an objective, and theeffects of the monomers, crosslinker and initiators on adsorption selectivity and the processconditions were optimized. The optimum conditions were: the molar ratios of Glutathione, acrylamide, N, N’-methylenebiacrylamide and hydrogen peroxide to N-vinylpyrrolidone were0.5,2.25,2.5,0.01765, and hydrogen peroxide to L-ascorbic acid was2:1, and thepolymerization temperature and time were35oC and30h, respectively. MIP prepared at theoptimum conditions presented favourable adsorption of Glutathione with a maximumseparation degree of2.84. Scatchard analysis revealed that heterogeneous binding sites wereformed in MIP.3. Silymarin, Naringin, Puerarin and Gallic Acid were used as target molecules, whichhave the similar molecular structure with Quercetin. The molecular size, molecular volumeand molecular polarity of the five materials were calculated by Gaussian and Chemoffice2006software. Thereafter, Quercetin MIP was selected to perform adsorption experiments from therespective mixture of Quercetin with the above four materials in same mass concentrations,different mass concentrations and different temperatures. The results showed that moleculesize was a main influence factor for adsorption separation degree of different flavonoids. If themolecular size of target molecule was bigger than that of Quercetin molecule, the separationdegree of Quercetin MIP to Quercetin increased with the decrease of the size differencebetween target molecule and Quercetin; if the molecular size of target molecule was smallerthan that of Quercetin molecule, the specific adsorption of MIP to Quercetin was not obvious.The matching character of molecular polarity was also a main influence factor for adsorptionperformance of Quercetin MIP. If the molecular polarity of target molecule was bigger orsmaller than that of Quercetin molecule, the separation degree of Quercetin MIP to Quercetinincreased with the decrease of the polarity difference between target molecule and Quercetin;if the molecular polarity of target molecule and Quercetin was similar, the separation degree ofQuercetin MIP to Quercetin was low. The molecular volume was also an influence factor foradsorption performance of Quercetin MIP. If the molecular volume of target molecule wasbigger than that of Quercetin molecule, the separation degree of Quercetin MIP to Quercetinincreased with the decrease of the size difference between target molecule and Quercetin; ifthe molecular volume of target molecule was smaller than that of Quercetin molecule, thespecific adsorption of MIP to Quercetin was not obvious. At the same time, the adsorptiontemperature was an influence factor for adsorption performance of Quercetin MIP. Highadsorption temperature was propitious to the adsorption reaction, and the absorptionequilibrium achieved at high temperature.