分子印迹固相萃取技术对六堡茶中表儿茶素的分离特性

以表儿茶素为模板分子,丙烯酰胺为功能单体,偶氮二异丁腈作为引发剂,乙二醇二甲基丙烯酸酯为交联剂,通过原位聚合法制备分子印迹聚合物。首先考察不同模板分子、功能单体、交联剂比例条件下表儿茶素分子印迹聚合物的特异性吸附能力。结果表明表儿茶素与丙烯酰胺、乙二醇二甲基丙烯酸酯物质的量比为1∶6∶40时,分子印迹聚合物的吸附效果最佳,其模板分子回收率KMIPs为84.62%,特异性识别因子Q为4.55;然后利用扫描电子显微镜和红外光谱技术对制备的印迹聚合材料进行表征;最后在毛细管电泳最优条件下对加载过固相萃取柱的过柱液与洗脱液进行检测,建立分子印迹固相萃取-毛细管电泳联用检测表儿茶素的方法。实验结果表明,分子印迹聚合物成功聚合,形貌良好且具有专一吸附特性。该方法适用于六堡茶中表儿茶素的检测。

Separation of L-Epicatechin in Liubao Tea by Molecularly Imprinted Solid Phase Extraction

Molecularly imprinted polymers (MIPs) were synthesized by in situ polymerization using L-epicatechin as the template molecule, acrylamide (AM) as the functional monomer, azobisisobutyronitrile (AIBN) as the initiator, and ethylene glycol dimethacrylate (EGDMA) as the cross-linking agent. Firstly, the specific adsorption capacity of L-epicatechin MIPs was evaluated as a function of the proportions of template molecule, functional monomer, and cross-linking agent. The results showed that when the molar ratio of L-epicatechin to acrylamide to ethylene glycol dimethacrylate was 1:6:40, MIPs exhibited the best adsorption capacity, with template molecule recovery (KMIPs) of 84.62% and specific recognition factor (Q) of 4.55. Scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FT-IR) were used to characterize the MIPs. Finally, we used capillary electrophoresis to detect the effluent and the eluate under optimum conditions. As a result, a molecularly imprinted solid phase extraction-capillary electrophoresis (MISPE-CE) method for the determination of L-epicatechin was developed. The experimental results showed that molecularly imprinted polymers were successfully synthesized with good morphology and specific adsorption characteristics. This method is feasible for the analysis of L-epicatechin in Liubao tea.