双向电堆积与毛细管电泳联用对茶叶中咖啡酸及没食子酸的测定

采用在线双向电堆积与毛细管电泳联用技术测定茶叶中的有机酸离子。用砂芯取代盐桥隔离缓冲液与电极液,制成集成的双向电堆积装置,并用计算机程序控制分析过程。考察了电堆积时间、电堆积电压和样液体积等因素对富集倍数的影响。在优化的条件下,咖啡酸和没食子酸的富集倍数分别为24和20,检出限分别为0.4、0.2 mg/L。咖啡酸和没食子酸的线性范围分别为1.2~800 mg/L和0.8~800 mg/L。方法已应用于茶样中两种酸的测定,回收率为99%~109%。

Determination of Caffeic Acid and Gallic Acid in Tea Samples by Capillary Electrophoresis with Bi-directional Electrostacking

A bi-directional electrostacking combining with capillary electrophoresis method was proposed to analyze organic acid ions in tea samples.Salt bridges were replaced by porous cores to separate running buffer and electrode solution,and the bi-directional electrostacking setup was improved to be integrative.The analytical procedure was controlled by a computer.The experimental parameters,including electrostacking time,applied voltage and sample volume,etc.were investigated.Under the optimal condition,the enri...