毛细管区带电泳法测定茶叶中咖啡因、茶氨酸、表儿茶素和表没食子儿茶素没食子酸酯

目的：建立毛细管区带电泳法测定茶叶中咖啡因、茶氨酸、(－)表儿茶素(EC)和(－)表没食子儿茶素没食子酸酯(EGCG)含量的分析方法。方法：以含有20mmol/L硼砂和磷酸盐(pH9.5)为电泳介质，在电压25kV、柱温25℃条件下分离和210nm波长处检测。结果：在8min内可将4种待测组分全部分离且各组分的质量浓度与峰面积呈良好的线性关系，相关系数r为0.9944～0.9995，检测限为0.001～0.01μg/mL，各组分的加标回收率为89.98%～102.7%，相对标准偏差小于9.11%。结论：本实验建立的方法直接用于茶叶中咖啡因、茶氨酸、EC和EGCG的测定，结果满意。

Determination of Caffeine,Theanine,(-)-Epicatechin and (-)-Epigallocatechin Gallate in Tea by Capillary Zone Electrophoresis

A capillary zone eletrophoresis method was proposed for the content determination of caffein, theanine, (-)-epicatechin and (-)-epigallocatechin gallate in tea. The electrolyte solution consisted of 20 mmol/L borax-phosphate (pH 9.5). The voltage and column temperature were 25 kV and 25 ℃, respectively. The detection wavelength was set as 210 nm. Complete separation of the four analytes was achieved within 8 min. A good linear relationship between absorbance and concentration was observed for each analyte with a correlation coefficient varying from 0.9944 to 0.9995. The limits of detection of this method were 0.001–0.01 μg/mL. Average spike recoveries of affein, theanine, (-)-epicatechin and (-)-epigallocatechin gallate in different kinds of tea varied from 89.98% to 102.7%, with RSDs less than 9.11%. This method has been successfully used for the determination of these compounds in tea samples.