重铬酸钾可见分光光度法测定绿茶中茶多酚总量的研究

研究重铬酸钾与茶多酚反应的最佳条件，建立了重铬酸钾可见分光光度法测定绿茶中茶多酚总含量的定量分析方法。在硫酸强酸性介质中重铬酸钾能氧化茶多酚，其吸光度随茶多酚浓度的增加而减小，且减小值与茶多酚的浓度呈线性关系。本方法的线性范围为0.00～7.21 × 10-5g/ml，相关系数为0.9994，RSD 在1.09%～2.44%(n=5)之间，回收率在98.3%～103.6% 之间，分析结果与高锰酸钾滴定法相一致。该方法所用仪器简单、操作方便、测定成本低，可应用于绿茶中茶多酚总含量的测定。

Study on Determination of Total Tea Polyphenols in Green Tea Using Visible Spectrophotometry with Potassium Dichromate

In the study, the reaction conditions of potassium dichromate and tea polyphenols (TP) were investigated and the spectrophotometric method for the determination of total tea polyphenols in green tea was established. In strong sulfuric acid medium potassium dichromate can oxidize tea polyphenols and its absorbance is reduced while tea polyphenols are added, and the reduced value is linear over the range of the concentration of total tea polyphenols. The linear range of the method is 0.00 to 7.21×10-5 g/ml tea polyphenols with the correlation coefficient of 0.9994, the RSD is 1.09% to 2.44% (n=5), and the recovery rate is 98.3% to 103.6%. These experimental results are consistent with those obtained by permanganometric titration. Furthermore, the instruments used in the method are simple and cheap. Therefore, this developed method can be successfully applied to the determination of total tea polyphenols in green tea.