电感耦合等离子体质谱法测定地质样品中锗和镉的干扰及校正
Interference and Its Elimination in Determination of Germanium and Cadmium in Geological Samples by Inductively Coupled Plasma-Mass Spectrometry
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摘要: 采用HF-HClO4-HNO3分解样品,8 mol/L HNO3提取剂,外标法校准,电感耦合等离子体质谱法同时测定地球化学样品中锗和镉.选择103 Rh为内标,确定了最佳仪器参数,研究了Zn、Zr、Sn、Ce、Nd、Sm对Ge和Cd的干扰,试验选择质量数74 Ge和114 Cd 作为测定同位素,采用数学公式校正法校正了来自Nd和Sm的二次电离离子对 Ge 的干扰、Sn对Cd的同质异位素干扰.方法检出限(10s)分别为Ge 30 ng/L、Cd 15 ng/L,精密度(RSD,n=15)为Ge 1·35%、Cd1.47%.对多种国家一级标准物质进行分析验证,结果与标准值相符.方法适用于地质样品中微量锗和镉的测定.Abstract: The samples were decomposed by mixed acid of HF-HClO4-HNO3. Germanium and cadmium in sample solutions were determined by inductively coupled plasmamass spectrometry with external calibration method. 74Ge and 114Cd were chosen as determining isotopes and 103Rh as internal standard. The instrument operating parameters were optimized and the interference from coexistent elements of Zn, Zr, Sn, Ce, Nd, Sm to the determination of Ge and Cd was studied. Interference from Nd2+and Sm2+ to Ge and from Sn isobars to Cd were calibrated by the mathematical method. The detection limits (10SD） of method for Ge and Cd are 30 ng/L and 15 ng/L respectively. The method has been verified by the determination of Cd and Ge in geological standard reference materials and the results are in agreement with certified values with precision of 1.35％RSD for Ge and 1.47％RSD for Cd. The method is suitable for the determination of trace Ge and Cd in geological samples.
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Key words:
- inductively /
- coupled /
- plasma-mass /
- spectrometry /
- interference /
- calibration /
- germanium /
- cadmium /
- geological /
- sample /
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