羟肟酸铁比色法测定烟草根系分泌有机酸总量

Determination of Organic Acid in Tobacco Root by Ferric Hydroxamate Spectrophotometry

为了测定根系分泌物中有机酸的总量,笔者采用分光光度计测量的新方法,通过乙酸、苹果酸和柠檬酸进行线性关系分析,用正交试验设计确定各反应条件的最佳参数和最优组合,使用该方法对3个品种‘农大202’、‘NC89’和‘K326’根系分泌物中有机酸的总量进行测定。结果表明:0.08 mol/L盐酸羟胺、0.4 mol/L DDC、0.7 mol/L氯化铁、50℃、30 min反应时长和520 nm波长是显色反应的最优条件组合,而且建立的方法具有线性范围宽、准确度高、回收率高和检出限低等优点。羟肟酸铁比色法是测定烟草根系分泌有机酸总量的好方法,其方法简便易行。

In order to determine the amount of organic acids in root exudates, the authors usedspectrophotometer measurement method to analyze the linear relationship between the acetic acid, malic acidand citric acid, and the orthogonal test design to determine the reaction condition of the optimal parameters andthe optimal combination, thus to measure the amount of the organic acids of‘Nongda202＇, NC89 and K326 inroot exudates. The results showed that the optimal condition for the color reaction was as follows： 0.08 mol/Lhydrochloric hydroxylamine, 0.4 mol/L DDC, 0.7 mol/L Fe Cl3, 50℃, 30 min reaction time and 520 nmwavelength. The advantages of the established method included wide linear range, high accuracy, high recoveryrate and low detection limit. Therefore, the colorimetric method of the ferric hydroxide, which was simple andeasy to operate, was a good method to determine the total amount of organic acids in root exudates of tobacco.