电感耦合等离子体质谱法测定镍钨合金中铈

根据镍钨难溶特性,采用硝酸低温加热溶解样品后,多次滴加过氧化氢螯合样品表面包覆的氧化钨以保证样品被溶解完全,建立了电感耦合等离子体质谱法(ICP-MS)测定镍钨合金中痕量铈的方法。在选定的仪器测定条件下,选择¹⁴⁰Ce为待测元素同位素,以20 μg/L 铑为内标进行测定,以铈与铑的信号强度比值为纵坐标,铈质量浓度为横坐标绘制校准曲线,结果表明:二者呈良好的线性关系,线性回归方程为y=0.688 x+0.047,线性相关系数R²=0.999。方法中铈检出限为0.08 μg/g,测定下限为0.26 μg/g。方法应用于实际样品中铈的测定,测得结果的相对标准偏差(RSD,n=9)为0.10%～1.0%,回收率为88%～117%。

Determination of cerium in nickel-tungsten alloy by inductively coupled plasma mass spectrometr

According to the insoluble characteristics of nickel-tungsten alloy, the sample was dissolved with nitric acid by heating at low temperature. The tungsten oxide coated on sample surface was chelated by adding hydrogen peroxide to fully dissolve the sample. Then, the determination method of trace cerium in nickel-tungsten alloy by inductively coupled plasma mass spectrometry (ICP-MS) was established. Under the selected instrumental conditions, the ¹⁴⁰Ce was used as the isotope. The rhodium (20 μg/L) was selected as internal standard for the determination. The calibration curve was plotted using the signal strength ratio of cerium and rhodium as the vertical coordinate and using the mass concentration of cerium as the horizontal coordinate. The results showed that the linear relationship was good. The linear regression equation was y=0.688 x+0.047 with linear correlation coefficient of R²=0.999. The detection limit of cerium was 0.08 μg/g. The lower determination limit was 0.26 μg/g. The proposed method was applied to the determination of cerium in actual samples, and the relative standard deviations (RSD, n=9) of determination results were between 0.10% and 1.0%. The recoveries were between 88% and 117%.