电感耦合等离子体原子发射光谱法测定铀氧化物中微量碱金属元素

采用电感耦合等离子体原子发射光谱法(ICP-AES)测定铀氧化物中Li、Na、K、Cs等碱金属元素的含量。用CL-TBP萃淋树脂为固定相、3 mol/L硝酸溶液为流动相,定量地分离基体铀与杂质元素,溶液中的杂质含量用光谱仪测定。对仪器工作参数的优化条件进行了介绍,确定了元素的分析波长,进行了标准曲线与工作曲线无显著性差异的一致性评价,采用峰高积分法降低了Cs元素的电离干扰。用方法比对和加标回收两种方式验证了实验方法的准确性与有效性。结果表明:Li、Na、K、Cs的相对标准偏差优于15%(n=6),分析方法回收率为90%～110%,在Li质量分数为21.2μg/g时,测量结果的相对扩展不确定度U_rel(Li)=7.2%(K=2)。

Determination of Trace Alkali Metal Elements in Uranium Oxide by Inductively Coupled Plasma Atomic Emission Spectrometry

The content of trace alkali metal elements such as Li, Na, K and Cs was determined by ICP-AES. The method uses 3 mol/L nitric acid solution for leaching solution, CL-TBP resin for stationary phase to separate uranium and impurity. The level of impurity in the solution was measured by spectrometer. In this paper, the optimization working parameters of the instrument was introduced, the wavelength of elements was determined and no significant difference between standard curve and working curve was evaluated. The ionization interference of Cs was reduced by the peak-height integral method. The accuracy and validity of this method was verified by different techniques and standard addition recovery. The results show that the relative standard deviations of Li, Na, K and Cs are better than 15%(n=6). The recovery of the method is 90%-110%. While the content of Li is 21.2 μg/g, the relative extended uncertainty （U_rel(Li)） of measured results is 7.2%(K=2).