蒸馏分离-电感耦合等离子体质谱法测定地球化学样品中痕量钌和锇

建立了蒸馏分离-电感耦合等离子体质谱法测定地球化学样品中痕量钌和锇的分析方法。进行了蒸馏温度和时间、氧化剂、吸收液等条件的选择,消除了等离子体质谱法测定钌和锇的干扰。样品用过氧化钠熔融,酸化后以高锰酸钾-过硫酸钾-氯化钠作为同时蒸馏钌和锇的氧化剂,采用20 mL 50 g/L水合肼溶液同时吸收从混合物中分离出来的痕量钌和锇,用电感耦合等离子体质谱法测定。方法的检出限Ru为0.020 ng/g,Os为0.015 ng/g;方法加标回收率Ru为94.0%~102.7%,Os为96.0%~102.4%;精密度为4.72%~9.58%(n=12)。方法经国家一级标准物质验证,钌和锇的测定结果与标准值相符。

Determination of Trace Ruthenium and Osmium in Geochemical Samples by Inductively Coupled Plasma-Mass Spectrometry with Distillation Separation

An inductively coupled plasma-mass spectrometric (ICP-MS) method for determination of trace ruthenium and osmium in geochemical samples with distillation separation was established. The elimination of the interferences on ICP-MS measurements were studied through the experiments. Samples were decomposed with Na₂O₂ fusion method and the melts were dissolved with acid solution. KMnO₄+K₂S₂O₄+NaCl were added to the sample solution as an oxidant and 20 mL 5% hydrazine hydrate was selected as an absorbent. Trace ruthenium and osmium in the sample solution were separated by distillation from matrix and determined by ICP-MS. Distillation conditions, such as temperature, time, oxidant and absorbent were tested and optimized. The detection limits of the method were 0.020 ng/g for Ru and 0.015 ng/g for Os. Recoveries of the method were 94.0%~102.7% for Ru and 96.0%~102.4% for Os with precision of 4.72%~9.58%RSD(n=12) for both elements. The reliability of the method has been tested by determination of trace Ru and Os in National Standard Reference materials and the results are in agreement with the certified values.