砂岩铀矿地质样品中铀含量仲裁分析方法——同位素稀释电感耦合等离子体质谱法

Arbitral Analysis of Uranium in Sandstone Uranium Geological Samples by Isotope Dilution Inductively Coupled Plasma Mass Spectrometery

本工作研究铀矿地质样品中铀含量仲裁分析方法——同位素稀释电感耦合等离子体质谱法。样品经混酸密闭消解溶矿，采用浓缩铀为稀释剂，使用高分辨电感耦合等离子体质谱测定铀同位素比值，进而计算样品中的铀含量。本方法具有明晰的计量溯源特性，铀的测量范围为1-10000μg/g，对于铀含量约为4μg/g的砂岩样品，相对扩展不确定度小于4.0%（扩展因子K=2.57），可满足砂岩铀矿地质样品中铀含量仲裁分析要求。

A method for determination of uranium in sandstone uranium geological samples by isotope dilution inductively coupled plasma mass spectrometry （ID-ICP-MS） was evaluated. Samples were digested and spiked with highly enriched uranium （HEU） in a closed vessel using mixed acids, and 235^U/238^U ratio was measured by high resolution ICP-MS. The method is capable of determining uranium contents of 1-10 000 μg/g with relative expanded uncertainty of 4.0% at uranium contents of 4 μg/g, and is qualified for the arbitral analysis of uranium in sandstone uranium geological samples.