磷钼酸铵分光光度法测定茶多酚

Determination of Tea Polyphenols by Ammonium Phosphomolybdate Spectrophotometry

在pH=5.3的醋酸-醋酸铵(HAc-NH4Ac)介质中,茶多酚与磷钼酸铵结合形成磷钼酸酯,溶液最大吸收波长为320nm。茶多酚的浓度在0.01—0.20mg/mL范围内遵守比耳定律,其表观摩尔吸光系数为ε=1.22×105L.mol-1.cm-1。方法选择性较好,用于茶汤中总茶多酚含量的测定,所得结果与标准方法测定结果基本一致。

In HAc-NH4Ac at pH=5.3 buffer solution,the tea polyphenol reacts with ammonium phosphomolybdate and forms the ester phosphomolybdate. The wavelength for the spectrophotometric determination is 320nm. Beer＇s law is obeyed in the range of 0. 01--0. 20mg/mL,and the apparent molar absorptivity ε is 1.22× 10^5L · mol^-1 · cm^-1. The content of tea polyphenols in the tea soup was determined.