Determination of hydrolyzable tannins (gallotannins and ellagitannins) after reaction with potassium iodate
Determination of hydrolyzable tannins (gallotannins and ellagitannins) after reaction with potassium iodate
复制标题
DOI：
10.1021/jf0111155
复制
发表时间：
2002-03-27
影响因子：
6.1
通讯作者：
Hagerman, AE
中科院分区：
文献类型：
--
作者：
Hartzfeld, PW;Forkner, R;Hagerman, AE
一种广泛使用的分析与KlO（3）反应后的可水解单宁的方法已被修改为包括甲醇分解步骤，然后用KlO（3）氧化。在新方法中，水解单宁（没食子单宁和鞣花单宁）在甲醇/硫酸中于85 ℃下反应20 h，以定量释放没食子酸甲酯。干燥的植物样品可以在相同的条件下进行甲醇分解，将可水解的单宁转化为没食子酸甲酯。没食子酸甲酯在pH5.5，30 ℃下被KIO（3）氧化，形成λ（max）为525 nm的发色团，其通过比色法测定。该方法的检测限为1.5马克杯的没食子酸甲酯，并与植物样品，相对标准偏差小于3%。
A widely used method for analyzing hydrolyzable tannins afer reaction with KlO(3) has been modified to include a methanolysis step followed by oxidation with KlO(3). In the new method, hydrolyzable tannins (gallotannins and ellagitannins) are reacted at 85 degreesC for 20 h in methanol/sulfuric acid to quantitatively release methyl gallate. Dried plant samples can be methanolyzed under the same conditions to convert hydrolyzable tannins to methyl gallate. Oxidation of the methyl gallate by KlO(3) at pH 5.5, 30 degreesC, forms a chromophore with lambda(max) 525 nm, which is determined spectrophotometrically. The detection limit of the method is 1.5 mug of methyl gallate, and with plant samples, relative standard deviations of less than 3% were obtained.