纸层析-分光光度法检测茶氨酸

Determination of Theanine in Tea(Camellia sinensis L.) by Paper Chromatography-Spectrophotometry

为了满足普通实验室对茶中茶氨酸测定的需要,研究了茶氨酸的纸层析-分光光度检测方法。结果表明,用茚三酮-乙醇水溶液做展层剂,对茶苗根、芽叶和茶叶的水浸提液进行纸层析,能够有效地将茶氨酸与其它氨基酸分离,紫色色斑清晰而均匀。用乙醇溶液洗脱色斑后用分光光度计在570nm比色,在20～70μL茶氨酸溶液点样量范围内其含量与吸光度呈线性关系。本方法检出限为0·0057mg·mL-1,测定下限为0·0191mg·mL-1,平均回收率90·28%～115·38%,平均相对标准差1·51%,具有安全、药品种类少和操作步骤简单等特点。

To meet the needs of ordinary laboratory determination of theanine, paper chromatographic- spectrophotometry was developed. The results showed that by paper chromatography, ninhydrin-ethanol water solution could effectively separate theanine from other amino acids extracted in the water from roots or shoots of tea seedling or from tea. The purple stains were clear and even. After the stains were eluted with ethanol solution, theanine content could be assayed with the spectrophotometer at 570 nm. The theanine content appeared a linera relationship with the absorption value when the solution was spotted on the paper at the range of 20-70μL. The detection limit was 0.0057 mg·mL-1 and the lowest detection limit was 0.0191 mg·mL-1. The average recovery ranged from 90.28% to 115.38%, and the average relative standard deviation was 1.51%. The paper chromatography-spectrophotometry characterizes safety, fewer chemicals, and easy to operate.