基体酸化分离-电感耦合等离子体质谱法测定高纯硒中Al、Fe、Sn、Te、Sb、Ti、Ga、Pb、Ge

建立了硒酸化分离-电感耦合等离子体质谱(ICP-MS)测定高纯硒中Al、Fe、Sn、Te、Sb、Ti、Ga、Pb、Ge等9种痕量杂质元素的方法。利用基体硒酸化生成硒酸具有低沸点的特性分离基体,有效克服了基体对待测元素的干扰和对仪器进样系统的污染。还研究了酸的加入量对分离效果的影响;测定不同基体~(74)Se和~(76)Se残留下~(74)Ge(丰度R=36.28%)和~(76)Ge(丰度R=7.61%)的值;将该方法与挥发二氧化硒分离基体法、阳离子交换分离富集法进行对照,比较了方法的有效性。结果表明,在硫酸高温冒烟下,酸的加入量为4mL时,可以实现基体99.99%分离;基体对~(74)Ge和~(76)Ge的干扰可以完全消除。挥发二氧化硒分离基体法及阳离子交换分离富集法的对照实验表明,在选定的实验条件下,方法检出限(3σ)介于0.01~0.02μg/g,相对标准偏差(RSD)为2.5%~5.3%,加标回收率为90%~110%。此方法快速、简便、准确可靠,能够满足纯度为5N(99.999%)的高纯硒中9种杂质元素的测定。

Acidification-Separation of Matrix and Determination of Impurities in High Purity Selenium by ICP-MS

A method of ICP-MS after acidification separation was developed for the determination of nine different impurities (including Al, Fe, Sn, Te, Sb, Ti, Ga, Pb, Ge) in high purity selenium. The interferences on analytes and the pollution of sample introduction system were efficiently avoided by separation impurity elements from matrix selenium by means of low boiling point of selenic acid. The influences of dosage of sulfuric acid to separation effects were studied. The variation trend of ⁷⁴Ge and ⁷⁶Ge contents with the different amounts of residual selenium in sample solution was also determined. The analytical results proved to be accurate and validated by comparison of proposed methods with SeO₂ separation and ion exchange separation. Under the optimized conditions, over 99.99% of the matrix selenium was removed by acidification separation with the acid addition was 4 mL, which eliminated the matrix effect and spectra interference in the following ICP-MS detection. The result shows that the detection limit of the method is 0.001-0.002 μg/g, the RSD is 2.5%-5.3%, and the recovery of standard addition is 90%-110%. The method is simple, applicative and suitable for the determination of impurities in high purity selenium of 99.999%.