分子印迹聚合物纯化甘草酸

Purification of Glycyrrhizic Acid by Molecular Imprinted Polymers

摘要:

以甘草酸、不同单体（甲基丙烯酸、甲基丙烯酸羟乙酯和4-乙烯基吡啶）和交联剂（二乙烯基苯和乙二醇二甲基丙烯酸酯）为原料，在乙腈和N,N-二甲基甲酰胺(DMF)的混合液中，以偶氮二异丁腈为引发剂，采用沉淀聚合法制备了一系列分子印迹聚合物(MIPs)。采用FTIR、SEM和BET对MIPs进行了表征与测试，优化了MIPs的制备工艺。结果表明：当交联剂为二乙烯基苯、单体为甲基丙烯酸、甘草酸与甲基丙烯酸的物质的量比为1:10、致孔剂为25mL乙腈和8mL DMF的混合液时，MIPs对甘草酸的吸附性能最好。在5g/L的甘草酸溶液中，MIPs对甘草酸的平衡吸附量可达398.5mg/g，印迹因子为3.73。并对MIPs的吸附动力学和吸附等温线进行了研究。利用分子印迹固相萃取技术(MISPE)对甘草提取物进行精制，将甘草提取物中甘草酸的质量分数由11.27%提高到73.10%，回收率为86.87%。

Abstract:

With glycyrrhizic acid, different monomers (methacrylic acid, hydroxyethyl methacrylate and 4-vinyl pyridine) and cross-linkers (divinylbenzene and ethylene glycol two methacrylate) as raw materials, a series of molecularly imprinted polymers (MIPs) were prepared by precipitation polymerization in the mixed solution of 25 mL acetonitrile and 8 mL N,N-dimethylformamide (DMF) with azodiisobutyronitrile as initiator.The MIPs were characterized and tested by FTIR, SEM and BET.The preparation process of MIPs was optimized, and the results showed that when the cross-linker was divinylbenzene, the monomer was methacrylic acid，the molar ratio of glycyrrhizic acid and methacrylic acid was 1:10 and the porogen was the mixed solution of 25 mL acetonitrile and 8 mL DMF, MIPs showed the best adsorption performance for glycyrrhizic acid.The equilibrium adsorption capacity of glycyrrhizic acid was 398.5 mg/g and the imprinting factor was 3.73 in glycyrrhizic acid solution of 5 g/L.The adsorption kinetics and adsorption isotherm of MIPs were studied.The extract of licorice was refined by molecular imprinted solid phase extraction (MISPE),and the mass fraction of glycyrrhizic acid was increased to 73.10% from 11.27%with 87.1% recovery yield.