分光光度法测定茶游离氨基酸总量标准溶液的选择

Selection of standard solution for determination of total free amino acids in tea by spectrophotometry

讨论利用GB/T 8314-2013分光光度法测定茶叶中游离氨基酸总量时使用不同标准溶液测定结果的差别。分别使用茶氨酸和谷氨酸标准溶液制作标准曲线,茶叶中游离氨基酸总量测定结果存在显著差异。茶氨酸、谷氨酸标准曲线的相关系数(r^2)分别为0.9860,0.9942。分别采用两种标准曲线,测定结果的标准偏差分别为0.789%,0.659%(n=15),加标回收率分别为68.28%,94.63%。试验结果表明用谷氨酸制作标准曲线优于茶氨酸。建议在茶叶游离氨基酸总量测定中采用谷氨酸标准工作溶液。

The difference of the results from determination of total free amount amino acids in tea by spectrophotometry according to GB/T 8314-2013 with theanine or glutamic acid standard solutions.There were significant differences between the detection results of total amount free amino acids in tea by two standard working solutions.The correlation coefficients of two standard curves were 0.9860 and 0.9942,respectively.The standard deviation of detection results by two standard curves was 0.789%and 0.659%(n=15),and the recovery rates were 68.28%and 94.63%,respectively.It showed that the detection result by glutamic acid as the standard was better than that by theanine as the standard.Glutamic acid should be suggested to be used to make the standard working solution in the determination of total free amino acids in tea.