直读显色快速检测绿茶中的茶氨酸

本研究首先基于溶胶-凝胶方法成功构筑了茚三酮/纳米二氧化钛纳米材料,将其作为纳米显色剂打印在高效薄层板上茶氨酸所对应的比移值（R_f）处。以乙醇：冰乙酸展开体系对适当脱色处理后的茶叶浸出物进行快速薄层直读显色分析。结果表明,在优化后的展开条件下该直读条带能够有效地分离茶叶提取物中多种氨基酸,所构筑的新型纳米显色剂对目标氨基酸茶氨酸实现了灵敏的直读显色,自显色后条带色斑均匀清晰,其颜色深浅度与其浓度之间有明确的半定量关系。本研究构建的直读显色条带具有安全、简便快捷、成本低等优点,在农产品品质鉴定与现场快速检测氨基酸等领域有着广泛的应用前景。

Rapid Detection of Theanine in Green Tea Based on Direct-reading Colorimetric Strips

In this study, ninhydrin/titanium dioxide nanomaterials were constructed by using Sol-Gel method. These nanomaterial were then used as direct-reading colorimetric materials and printed on the surface loci of thin layer plate where theanine would migrate according to its retardation factor (Rf). In addition, ethanol: acetic acid developing system was chosen as developing reagent, the extraction solution of tea after being decolorized by ethyl acetate was analyzed by thin layer chromatography (TLC) via direct-reading colorimetric reaction. The results showed that the current direct-reading strip could effectively separate several amino acids in tea extraction under optimized conditions. The new constructed colorimetric nanomaterials had achieved a sensitive direct-reading coloration results for the target amino acid theanine, and the color spots on the strip were uniform and clear after self-coloration. Moreover, its color depth had a clear semi-quantitative relationship with its concentration. The current colorimetric strip has a serial of advantages including safety, easy-operation, convenient and low cost, and has a broad application prospect in fields such as quality identification of agricultural products and on-site rapid detection of amino acids.