Department of Chemistry, Fudan University, Shanghai, PR China.
J Sep Sci. 2010 Apr;33(8):1079-84. doi: 10.1002/jssc.200900647.
In this work, for the first time, microwave-assisted extraction (MAE) followed by CE was developed for the fast analysis of catechin and epicatechin in green tea. In the proposed method, catechin and epicatechin in green tea samples were rapidly extracted by MAE technique, and then analyzed by CE. The MAE conditions and the method's validation were studied. It is found that the extraction time of 1 min with 400 W microwave irradiation is enough to completely extract catechin and epicatechin in green tea sample, whereas the conventional ultrasonic extraction (USE) technique needs long extraction time of 60 min. The method validations were also studied in this work. The calibration curve shows good linearity in 0.01-3 mg/mL for catechin (R(2)=0.993), and 0.005-3 mg/mL for epicatechin (R(2)=0.996), respectively. The RSD values for catechin and epicatechin are 0.65 and 2.58%, respectively. This shows that the proposed method has good reproducibility. The proposed method has good recoveries, which are 118% for catechin and 120% for epicatechin. The proposed method was successfully applied to determination of the catechin and epicatechin in different green tea samples. The experiment results have demonstrated that the MAE following CE is a simple, fast and reliable method for the determination of catechin and epicatechin in green tea.
在这项工作中，首次开发了微波辅助提取（MAE）结合 CE 用于快速分析绿茶中的儿茶素和表儿茶素。在所提出的方法中，通过 MAE 技术快速提取绿茶样品中的儿茶素和表儿茶素，然后通过 CE 进行分析。研究了 MAE 条件和方法的验证。结果发现，用 400 W 微波辐射提取 1 分钟足以完全提取绿茶样品中的儿茶素和表儿茶素，而常规的超声提取（USE）技术需要 60 分钟的长提取时间。本工作还研究了方法验证。校准曲线在 0.01-3 mg/mL 范围内对儿茶素（R(2)=0.993）和 0.005-3 mg/mL 范围内对表儿茶素（R(2)=0.996）均具有良好的线性。儿茶素和表儿茶素的 RSD 值分别为 0.65%和 2.58%。这表明该方法具有良好的重现性。该方法具有良好的回收率，儿茶素回收率为 118%，表儿茶素回收率为 120%。该方法成功应用于不同绿茶样品中儿茶素和表儿茶素的测定。实验结果表明，MAE 结合 CE 是一种简单、快速、可靠的方法，用于测定绿茶中的儿茶素和表儿茶素。
