高效液相色谱法测定武夷岩茶中咖啡碱的条件探讨

The Condition of Determination for Caffeine in Wuyi Rock Tea by HPLC

文章主要探讨采用高效液相色谱仪（HPLC）测定武夷岩茶（以肉桂为例）中咖啡碱含量的影响因素和条件.采用C18（100 mm×4.6 mm）的色谱柱,以甲醇-水（60-40）为流动相,检测波长为275nm.实验结果表明：茶叶样品中咖啡碱含量与峰面积在标准曲线范围内线性良好,线性回归方程为Y=51.439X＋37.053,R2=0.9999,另外在MgO添加量为0.5 g,沸水浴中浸提时间为30 min时,测得咖啡碱含量的相对标准偏差为0.63％,加标回收率为92.0 ％～102.0％.该方法简单、快速、准确,且能应用于不同武夷岩茶品种中咖啡碱的检测.

An HPLC method for detecting the content of caffeine in wuyi rock tea （Rougui tea for example） was established, The conditions and influence factors of test condition was studied. The ODS C 18 column （100mm×4.6mm） was used with the mobile phase of methanol-water （60 ： 40）, the UV- detection wavelength was 275 nm. The experimental results show that the content of caffeine in tea samples showed a good liner relationship with the peak area in the standard curve and the regression equation was Y=51.439＋37.053X, R2 = 0.9999. Furthermore, the relative standard deviation （RSD） of measured caffeine content was 0.63 % and the recovery was from 92.0 % to 102.0 % while the addition of MgO is 0.5 g and the extraction duration is 30 rain with the boiling water bath. The developed method was simple,rapid and accurate, and can be applied for the determination of caffeine in Wuyi rock tea with different types.