库仑滴定法测定黄磷的砷含量

Determinatiom of arsenic content of yellow phosphorus by coulometric titration

砷是黄磷中普遍存在又危害较大的杂质,为了寻找一种便捷准确的测砷方法,尝试采用库仑滴定法测量黄磷中砷含量。黄磷试样用硝酸消解为水溶液后,以硼氢化钾为氢化剂使黄磷中五价砷形成砷化氢气体,砷化氢气体逸出进入电解系统并发生反应,依据反应的电量转移计算出样品砷含量。检测的结果与采用氢化发生-原子荧光法的结果一致,而且该法具有更为快捷、检测范围更宽的特点,是测量黄磷砷含量的理想方法,尤其适合作为黄磷生产企业的快速质量监控方法。

Arsenic is a ubiquitous impurity which seriously hazards the yellow phosphorus product.In order to find a convenient and accurate method of measuring arsenic content,coulometric titration was attempted to be adopted.After the yellow phosphorus sample was digested by nitric acid into the water solution,pentavalent arsenic in yellow phosphorus was turned into AsH3 gas with potassium borohydride as hydrogenating agent.Then AsH3 gas would escape and enter into the electrolysis system.Arsenic content could be calculated based on the transformation of electrical quantity of the reaction.Test result with coulometric titration was not only in accordance with that measured by HG-AFS method,but also the new method was characterized by faster operation and wider detection range and it′s especially suitable for rapid quality monitoring for the enterprises.