常量铀钚的硝酸溶液中微量草酸的分析

草酸对铬酸钾氧化甲基红的褪色反应有显著催化作用，基于单纯硝酸草酸体系中微量草酸的测定方法，进一步考察Mn²⁺、UO²⁺₂和Pu⁴⁺对草酸测定的影响，并通过H柱消除体系中金属离子的干扰，考察了金属离子去除情况下分析方法的加标回收率和精密度。结果表明：草酸浓度在0~10.00 μmol/L的范围内遵循比尔定律，线性回归方程为：1/ΔA=0.163 8c(H₂C₂O₄)+0.837 2，相关系数r=0.999 9。方法应用于实际样品的测定，加标回收率在101%~102%之间，检出限为0.07 μmol/L，相对标准偏差约0.76%~1.37%(n=5)，满足常量铀钚的硝酸溶液中微量草酸的分析需求。

Analysis of Trace Oxalic Acid in Nitric Acid Solution Containing Constant Uranium and Plutonium

Oxalic acid has a significant catalytic effect on the fading reaction of potassium chromate oxidizing of methyl red.According to the catalytic kinetic spectrophotometric method has been developed for determination of micro oxalate acid in pure nitric acid system,the influence of Mn²⁺,UO₂⁺²and Pu⁴⁺on determination of oxalic acid was further investigated.The H column can eliminate the interference of metal ions in the system,and the standard recovery and precision of the method were determinate.The results show that the concentration of oxalic acid obeyes the Beer’s law in the range of 0-10.00μmol/L and the regression equation is 1/ΔA=0.1638 c(H₂C₂O₄)+0.8372 with the correlation coefficient r of 0.9999.The recoveries of the studied compound are in the range of 101%-102%with the detection limit of 0.07μmol/L,and the relative standard deviation are 0.76%-1.37%(n=5).The method can be used for a rapid and cost-effective alternative for determination of oxalic acid in nitric acid containing constant uranium and plutonium.