电感耦合等离子体质谱法测定高纯锌中7种痕量元素

高纯锌中铁、铜、镉、锑、铅、锡、砷元素含量低,基体和多原子离子干扰严重,这使得溶样后直接采用电感耦合等离子体质谱法(ICP-MS)对这7种元素进行测定的难度较大。实验表明:采用15 mL硝酸(1+2)低温溶解0.100 0 g样品,不进行基体分离,通过优化仪器参数、选择合适的同位素避免质谱干扰,采用标准加入法绘制校准曲线消除基体效应,可实现电感耦合等离子体质谱法(ICP-MS)对高纯锌中铁、铜、镉、锑、铅、锡和砷共7种痕量元素的测定。各元素校准曲线的相关系数在0.995 8到0.999 7之间,方法检出限为0.05~7.53 μg/L。采用实验方法对高纯锌实际样品中铁、铜、镉、锑、铅、锡和砷进行分析,测得结果的相对标准偏差(RSD,n=11)为2.4%~5.3%,加标回收率为96%~109%。按照实验方法测定纯锌样品中7种痕量元素,砷测得结果与电感耦合等离子体原子发射光谱法(ICP-AES)基本一致,锡和锑与原子荧光光谱法(AFS)基本一致,铁、铜、镉和铅与采用锌基体分离—ICP-MS基本一致。

Determination of seven trace elements in high purity zinc by inductively coupled plasma mass spectrometry

The content of iron, copper, cadmium, antimony, lead, tin and arsenic in high-purity zinc was very low, and the matrix and polyatomic ion interference was serious. As a result, the direct determination of those seven elements after sample dissolution by inductively coupled plasma mass spectrometry (ICP-MS) was difficult. The experiment showed that 0.100 0 g of sample was dissolved at low temperature with 15 mL of nitric acid (1+2). The mass spectrometry interference was avoided by optimizing the instrumental parameters and selecting proper isotopes, and the matrix effect was eliminated by plotting calibration curve with standard addition method. Thus, the determination of seven trace elements (including iron, copper, cadmium, antimony, lead, tin and arsenic) in high-purity zinc could be realized by inductively coupled plasma mass spectrometry(ICP-MS) without matrix separation. The correlation coefficients of calibration curves of elements were between 0.995 8 and 0.999 7. The detection limit of method was 0.05-7.53 μg/L. The content of iron, copper, cadmium, antimony, lead, tin and arsenic in actual high-purity zinc sample was determined by proposed method. The relative standard deviation(RSD, n=11) of the results were between 2.4% and 5.3%, and the recoveries were between 96% and 109%. The proposed method was applied to determination of seven trace elements in pure zinc sample. The results of arsenic were basically consistent with those obtained by inductively coupled plasma atomic emission spectrometry(ICP-AES). The results of tin and antimony were basically consistent with those obtained by atomic fluorescence spectrometry(AFS). The results of iron, copper, cadmium and lead were basically consistent with those obtained by ICP-MS after separation of zinc matrix.