茶叶中没食子酸含量测定的离子化萃取分离分光光度法研究

Ionization Extraction-Spectrophotometric Determination of Gallic Acid in Tea

通过离子化萃取分离的手段将没食子酸与儿茶素进行分离,并采用可见分光光度法对茶叶中没食子酸的含量进行准确测定。此外,还通过模拟实验确定离子化试剂的最佳用量以及溶媒体系的pH值,验证离子化萃取分离的可靠性。与其他用于没食子酸含量测定的方法相比,该方法具有操作简单、成本低、仪器要求不高等优点。将该方法用于检测茶样中没食子酸含量为(1.326±0.018)%,RSD为1.36%,测定值与已见报道相符。

In this study,gallic acid and catechin were separated by ionization extraction for the visible spectrophotometric determination of gallic acid content in tea.Simulated experiments were conducted to determine the optimal amount of ionization agent and environmental pH value,and the reliability of ionization extraction was validated.The developed method has some advantages over other methods,like simplicity,low cost and less instrumental requirements.In five replicate determinations,a commercial sample of Ya an Tibetan tea was determined by the method to have a gallic acid content of （1.326 ± 0.018）%,with 1.36% relative standard derivation.This result is very close to previously reported values.