HPLC法测定茶中茶氨酸、茶碱与咖啡因的含量

目的建立测定茶中茶氨酸、茶碱与咖啡因含量的方法,并测定其在不同茶中的含量。方法茶叶采用水作为溶剂加热回流提取,采用高效液相色谱法及梯度洗脱法。结果①茶氨酸对照品在0.026 4～1.762 0mg.mL-1质量浓度范围内线性关系良好(r=0.999 7);精密度的RSD值为0.98%(n=6);测得平均加样回收率为98.96%,RSD值为1.01%(n=5)。②茶碱对照品在0.014 3～0.954 0mg.mL-1质量浓度范围内线性关系良好(r=0.999 8);精密度的RSD值为1.21%(n=6);测得平均加样回收率为98.43%,RSD值为0.74%(n=5)。③咖啡因对照品在0.077 6～5.168 0mg.mL-1质量浓度范围内线性关系良好(r=0.999 6);精密度的RSD值为1.03%(n=6);测得平均加样回收率为99.43%,RSD值为0.91%(n=5)。④茶氨酸、茶碱与咖啡因含量(mg.g-1)范围分别为0.46%～12.70%,0.53%～32.78%和8.78%～24.12%,平均含量分别为6.08%,10.43%,19.04%。结论该方法简便易行,可用于茶叶的质量控制。

Determination of theanine,theophylline and caffeine in tea by HPLC

Objective To establish a high performance liquid chromatography(HPLC) method for the determination of the content of theanine,theophylline and caffeine in the various tea leaves.Methods Various tea leaves were extracted heating and refluxing to extract by using water as the solvent.HPLC with gradient elution was used to determine theanine,theophylline and caffeine.Results ①Theanine showed good linear relationship in the concentration range of 0.026 4-1.762 0 mg·mL-1(r=0.999 7);the RSD of precision of control article was 0.98%(n=6);the average rate of recovery was 98.96%,and RSD was 1.01%(n=5),respectively.②Theophylline showed good linear relationship in the concentration range of 0.014 3-0.954 0 mg·mL-1(r=0.999 8);the RSD of precision of control article was 1.21%(n=6);the average rate of recovery was 98.43%,and RSD was 0.74%(n=5),respectively.③Caffeine showed good linear relationship in the concentration range of 0.077 6-5.168 0 mg·mL-1(r=0.999 6);the RSD of precision of control article was 1.03%(n=6);the average rate of recovery was 99.43%,and RSD was 0.91%(n=5),respectively.④ The content of theanine,theophylline and caffeine were 0.46%-12.70%,0.53%-32.78% and 8.78%-24.12%,and the average content was 6.08%,10.43%,19.04%,respectively.Conclusion The method proved to be simple and easy to implement,and could be used to tea’s quality control.