不同茶叶中表没食子儿茶素没食子酸酯的含量测定

Determination of epigallocatechin gallate in different tea

目的建立反相高效液相色谱法检测茶叶中表没食子儿茶素没食子酸酯(epigallocatechin gallate,EGCG)的含量,并对比不同茶叶中EGCG的含量。方法对不同产地茶叶样品用70%甲醇提取10 min,提取后冷却至室温,提取溶液经过离心;采用反相色谱柱Agilent SB-C_(18)(4.6 mm×250 mm,5μm)检测,以流动相A(90mL乙腈:20 mL乙酸:2 mL乙二胺四乙酸二钠:888 mL水)、流动相B(800 mL乙腈:20 mL乙酸:2 mL乙二胺四乙酸二钠:178 mL水)梯度洗脱,流速1.0 mL/min,柱温35℃,检测波长278 nm。结果 EGCG在78.0~468.0μg/mL的范围内与峰面积积分值呈良好的线性关系(r^2=1.0000),平均加标回收率为95.6%,RSD为1.29%。结论该方法简单、灵敏、稳定、可靠,可用于不同茶叶EGCG的含量测定。实验同时发现,不同茶叶由于产地和工艺不同,EGCG含量差异较为明显。

Objective To establish a method for determining epigallocatechin gallate (EGCG) in tea by reverse phase high performance liquid chromatography (RP-HPLC), and compare the content of EGCG in different tea. Methods Different tea was extracted for 10 min by 70%methanol solution;extraction solution was placed at room temperature, and then centrifuged. The chromatographic column was Agilent SB-C18 (4.6 mm×250 mm, 5 μm). The mobile phase A was ACN: HAC: EDTA-2Na: H2O = 90:20:2: 888 and the mobile phase B was ACN:HAC:EDTA-2Na:H2O=800:20:2:178. The flow was 1.0 mL/min, the column temperature was 35 ℃ and the detection wavelength was 278 nm. Results EGCG had good linearity with the peak areas in 78.0~468.0 μg/mL (r2=1.0000). The average recovery was 95.6% and the RSD was 1.29%. Conclusion The method is simple, sensitive, stable and reliable and it can be used to detect the EGCG in tea. This paper also finds that EGCG content is obviously different in different tea due to the different origin and technology.