新试剂DCB－偶氮胂与铀（Ⅵ）显色反应的研究

Study of colour reaction of new reagent DCB-Arsenazo with uranium(Ⅶ)

系统地研究了ＤＣＢ－偶氮肿与铀（Ⅶ）的显色反应．实验证明，显色反应的时间短，络合物的稳定性好，灵敏度高．测得络合物组成比为Ｕ：Ｒ＝１：２，摩尔吸光系数为９０ｋＬ·ｍｏｌ－１·ｃｍ－１，在０～２１μｇ／２５ｍｌ内服从比尔定律，为目前测定铀的一种高灵敏度方法．

DCB-arsenazo is a new chromogenic reagent. The colour reaction of U(Ⅶ) with it has been studied systematically. The experimental results show that the time of colour reaction is short,the stability of the complex is good, the sensitivity Is high. It has been determined that the composition of complex is U (Ⅶ): R=1:2,the molar absorptivity kL ·mol-1·cm-1,Beer’s law is obeyed for U(Ⅶ) in the range 0～21 μg/25ml. This is one of the high sensitive methods for determination of uranium at the present.