分光光度法测定三氧化铀中微量溴  

Determination of Micro-Amount Bromide in Uranium Trioxide by Spectrophotometric Method

作　　者：牛俐珺[1] 张耀玲[1] 许君政[1] 杨掌众 汪南杰 吴王锁[1] 

机构地区：[1]兰州大学核科学与技术学院,兰州730000 [2]兰州核燃料厂,兰州732850

出　　处：《核化学与放射化学》2007年第4期226-230,共5页Journal of Nuclear and Radiochemistry

基　　金：国家自然科学基金资助项目(J0630962)

摘　　要：溴离子是核纯级铀产品生产中的主要质量控制指标之一，准确检测它的含量非常重要。三氧化铀样品用硝酸溶解后，以氯化银为载体与微量溴离子共沉淀，经离心分离，使之与大量铀和其他杂质元素分离，生成的溴化银用氢氧化钾和过氧化氢溶解，转化成可溶性的溴化物，以钼酸铵为催化剂，溴化物跟过量的溴酸钾反应放出溴单质，在叔丁醇介质中，溴与碱性品红显色，用分光光度法测定。实验结果表明，本方法具有高的灵敏度和低的检测下限，表观摩尔吸收系数κ＇为1．7×10^4L／（mol·cm），检出限为9μg／L，测定下限为0．13mg／L，测定溴离子的线性范围为0．2～1．6mg／L，线性相关系数为0．997，6次平行测定的相对标准偏差优于10％。加入4．00，8．00μg溴离子时的加标回收率为94％～103％。The content of bromide in the production of uranium trioxide is one of the most important control factors, so determining it accurately seems important. When uranium trioxide is dissolved in nitric acid, in the presence of AgNO3 solution, micro-amount bromide can be coprecipitated with AgCl. Bromide can be separated by centrifugation from a large amount of UO2^2＋ and other anions. In the existing of KOH and H2O2, AgCl can be changed into free bromide. By adding ammonium molybdate as catalyst, bromide and excessive KBrO3 can react and produce Br2. In the medium of tert-butanol-ethanol, Br2 can react with basic fuchsine and produce a purple compound which is stable, the bromide content is determined by spectrophotometric method. The results show that it is a highly sensitive method with low detection limit. Its apparent molar absorption coefficient κ＇ is 1.7 × 10^4 L/（mol . cm）. Its detection limit is 9 μg/L and determination limit is 0.13 mg/L. The linear relationship is in the range of 0.2-1.6 mg/L with a correlation coefficient of 0. 997. The relative standard deviation is less than 10% after it is determined six times at the same time. For bromide content of 4.00 and 8.00 μg, the bromide recovery obtained are between 94% and 103%.

关 键 词：分光光度法 微量溴离子 UO3 

分 类 号：O657.32[理学—分析化学]