[Objective] The study aimed to establish the method of measuring the gallic acid content in tea by ionized extraction separation and spectrophotometry. [Method] With the Ya′an Zang tea as the sample,the water extract from tea samples was prepared by using water extract method. First,the NaHCO3 was added into the water extract from tea samples to make the ionization treatment,then through the extraction and separation by using ethyl acetate the disturbance factor of gallic acid and catechin were separated out,at last,the content of gallic acid in the water layer of extraction raffinate phase was measured by using spectrophotometer. [Result] The content of gallic acid in the tea sample was (1.32±0.18)% and the relative deviation was 1.36%. The measured value accorded to the reported value in literature and the values of 5 parallel determinations was close each other. The recovery of standard addition in this measured method was 99.4%-103.2%,the RSD value for 3 repeations were lowed than 2.5%. [Conclusion] Compared with other experimental method,the method has obvious advantages such as simple operation,low cost and low requirement of instrument and had higher precision and accuracy in detecting the gallic acid content in tea sample.%[目的]建立离子萃取分离可见分光光度法测定茶叶中没食子酸含量的方法.[方法] 以雅安藏茶为样品,用水提法制备茶样浸提液.先在茶样浸提液中加入NaHCO3进行离子化处理,然后用乙酸乙酯萃取分离,将没食子酸与儿茶素等干扰成分进行分离,最后用分光光度计检测萃余相水层中没食子酸的含量.[结果]茶样中没食子酸含量为(1.32±0.18)%,相对偏差(RSD)为1.36%,测定值与文献报道相符,5次平行测定值十分接近.该测定方法的加标回收率为99.4%～103.2%,3次重复的RSD值均小于2.5%.[结论]与其他方法相比,该方法具有操作简单、成本低、对仪器要求不高等优点,用于检测茶样中没食子酸的含量时,其精密度和准确度均较高.
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