高效液相色谱法测定茶叶中的咖啡因

目的]建立HPLC法快速测定茶叶中的咖啡因。方法]色谱柱Zorbax-C8（4.6 mm×250.0 mm,5.0μm）;流动相为0.04 mol/L柠檬酸水溶液∶N,N-二甲基甲酰胺（DMF）∶四氢呋喃（THF）=90∶16∶4;流速为1.00 ml/min;柱温60℃;检测波长280 nm;进样量为10μl。结果]咖啡因在20~100μg/ml时,浓度与峰面积呈良好的线性关系（r=0.999 9）,加标回收率为98.9%~102.3%,相对标准偏差RSD为0.23%。结论]该方法简单、快速、准确,适用于茶叶和茶饮料中咖啡因含量的测定。

Determination of Caffeine in Tea by HPLC

Objective] The aim was to establish a rapid method by HPLC for determination of caffeine concentration in tea.Method] The conditions were: chromatographic column Zorbax-C8(4.6 mm×250.0 mm,5.0 μm),mobile phase consisting of a mixture of citric acid solution(0.04 mol/L)∶N,N-dimethyl formamide∶tetrahydrofuran=90∶16∶4,flow rate 1.00 ml/min,column temperature 60 ℃,detection wavelength 280 nm,the sample dose 10 μl.Result] When the concentration of caffeine was 20-100 μg/ ml,the perfect linearity between concentration and peak area ratio was obtained(r=0.999 9).The recovery rate was 98.9%-102.3%,the relative standard deviation was 0.23%.Conclusion] The method is simple,rapid and accurate,and can be used for determination of caffeine concentration in tea and tea drinks.