浓缩钼同位素的纯化新方法及质量分馏测定

摘要

基于三氧化钼易升华的特性,建立了一种纯化浓缩钼同位素试剂的新方法.采用天然丰度掺杂样品Synthetic-Mo对纯化过程中的氧化时间、样品加入量及真空蒸发温度等条件进行了优化.用高分辨等离子体质谱分析了样品中杂质的含量,计算得到纯化后95 Mo 和98 Mo 浓缩同位素试剂的纯度分别为99.992%和99.990%.通过多接收器等离子体质谱测定纯化前后样品中钼同位素的组成,δX/95 Mo( X=92,94,96,97,98,100)值均在仪器测量精度(<0.3‰)范围之内,未观察到明显的质量分馏现象.该方法能够满足校正质谱法对浓缩同位素试剂的要求,对建立高准确度的钼同位素丰度比测量方法具有重要意义.%A novel purification method for isotopically enriched molybdenum was established according to the differences in sublimation temperature of MoO3 comparing with other species. The oxidation time, sample volume and sublimation temperature in this procedure were optimized using Synthetic-Mo with nature Mo com-positions. As measured by HR-ICP-MS, Mo could be effectively separated from other matrix elements, and the purities of 95 Mo and 98 Mo were 99.992% and 99.990%, respectively, after purification. Isotopic composi-tions of Synthetic-Mo and Purified-MoO3 samples were determined by MC-ICP-MS, theirδX/95Mo(X=92, 94, 97 , 98 , 100 ) values were indistinguishable within analytical uncertainty (<0.3‰) , revealing that isotopic fractionation of Mo was unlikely during purification. The proposed purification method is of great importance in developing high-accuracy measurement method for isotopic compositions of Mo.