茶叶儿茶素总量的硫酸-香荚兰素检测方法研究

[目的]探讨硫酸-香荚兰素分光光度法检测茶叶中儿茶素总量的最佳条件。[方法]通过对反应温度、显色剂浓度和反应时间等条件的研究,确定硫酸-香荚兰素显色反应体系为：吸取10μl茶汤,加入2.5 ml质量分数为1%的香荚兰素/乙醇溶液和2.5 ml质量分数为30%硫酸/乙醇溶液,在20℃下反应5 min后,反应液在500 nm处测定吸光度值。[结果]该方法的相对标准差为0.055,变异系数为0.32%,平均回收率为98.29%。[结论]与盐酸-香荚兰素法相比,硫酸-香荚兰素法节省了操作时间,提高了试验效率,降低了试验成本,同时具有较高的灵敏度、准确性和稳定性,值得推广应用。

Sulfuric acid-vanillin Assay of the Total Amount of Tea Catechin

[Objective] To explore the sulfuric acid-vanillin assay which was made as color spectrophotometer total catechins in tea on the basis of the tea catechins hydrochloride-Vanillin assay.[Method] After adding 2.5 ml of 1% Vanillin/elcohol solution and 2.5 ml of 30% sulfuric acid/ethanol solution into 10 μl of tea at 20 ℃ for 5 min,the absorbance of the reaction solution were determined in 500 nm.[Result] The standard deviation of sulfuric acid-vanillin assay was 0.055,the coefficient of variation was 0.32%,and the average recovery was 98.29%.[Conclusion] Compared to the hydrochloride-vanillin assay,the novel sulfuric acid-vanillin assay saves the operator time,increases test efficiency and reduces the test cost.Moreover,it has high sensitivity,precision and stability,should be widely applied.