分子印迹聚合物纯化甘草酸

Purification of Glycyrrhizic Acid by Molecularly Imprinted Polymers

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（0.16 mmol）与甲基丙烯酸的物质的量比为1：10、致孔剂为25 mL乙腈和8 mL DMF的混合液时,MIPs对甘草酸的吸附性能最好。在5 g/L的甘草酸溶液中,MIPs对甘草酸的平衡吸附量可达398.5 mg/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考察。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%。

A series of molecularly imprinted polymers（MIPs） were prepared by precipitation polymerization in acetonitrile and N,N-dimethylformamide（DMF） mixed solvents using glycyrrhizic acid, different monomers（methacrylic acid, hydroxyethyl methacrylate and 4-vinyl pyridine） and crosslinking agents（divinyl benzene and ethylene glycol dimethacrylate） as raw materials and azodiisobutyronitrile as initiator. The MIPs were characterized by FTIR, SEM and BET. Moreover, the preparation process of MIPs was optimized. The results showed that when divinylbenzene was used as crosslinking agent, the molar ratio of glycyrrhizic acid（0.16 mmol） to methacrylic acid was 1 ： 10, and a mixture of acetonitrile（25 mL） and DMF（8 mL） was adopted as porogen, the obtained MIPs showed the best adsorption to glycyrrhizic acid. In 5 g/L glycyrrhizic acid solution, the equilibrium adsorption capacity of MIPs to glycyrrhizic acid was 398.5 mg/g and the imprinting factor was 3.73. The adsorption kinetics and adsorption isotherm of MIPs were studied. Meanwhile, the licorice extract was refined by molecularly imprinted solid phase extraction（MISPE）, and the mass fraction of glycyrrhizic acid increased from 11.27% to 73.10% with 86.87% recovery yield.