电感耦合等离子体质谱法测定钇铁合金中14种稀土杂质

采用硝酸-双氧水处理钇铁合金样品,以0.3mol/L硝酸为测定介质,选用¹⁰³Rh和¹⁸⁵Re作为内标元素对基体效应和测量信号进行补偿和校正,实现了电感耦合等离子体质谱法(ICP-MS)对钇铁合金中14种稀土杂质元素的测定。通过选择合适的同位素和干扰校正方程消除了质谱干扰;通过选择稀释因子为2000,即控制基体质量浓度为0.5mg/mL进行测定消除了基体效应的影响。在优化的实验条件下,14种稀土元素的校准曲线线性相关系数都在0.9999以上,各元素的检出限为0.003~0.020μg/L。将实验方法应用于钇铁合金样品中稀土杂质的测定,测定结果的相对标准偏差(RSD,n=11)介于0.97%~6.5%之间,加标回收率为96%~104%。采用实验方法对钇铁合金样品进行测定,同时采用基体匹配结合电感耦合等离子体原子发射光谱法(ICP-AES)进行方法对照试验,两种方法测定结果基本一致。

Determination of 14 rare earth impurities in yttrium-iron alloyby inductively coupled plasma mass spectrometry

The yttrium-iron alloy sample was treated by nitric acid-hydrogen peroxide system. ¹⁰³Rh and ¹⁸⁵Re were selected as internal standard elements for the compensation and correction of matrix effect and measuring signal in 0.3mol/L nitric acid as determination medium. The determination of rare earth impurity elements in yttrium-iron alloy by inductively coupled plasma mass spectrometry (ICP-MS) was realized. The mass spectrometry interference was eliminated by selecting proper isotopes and interference correction equation. The dilution factor was 2000. In other words, the mass concentration of matrix was controlled at 0.5mg/mL to eliminate the influence of matrix effect. Under the optimized experimental conditions, the linear correlation coefficients of calibration curves for 14 rare earth elements were all higher than 0.9999. The detection limits of elements were between 0.003μg/L and 0.020μg/L. The experimental method was applied for the determination of rare earth impurities in yttrium-iron alloy sample. The relative standard deviations (RSD, n=11) of determination results were between 0.97% and 6.5%, and the spiked recoveries were between 96% and 104%. The yttrium-iron alloy sample was determined according to the experimental method. Meanwhile, the inductively coupled plasma atomic emission spectrometry (ICP-AES) combined with matrix matching method was also adopted for comparison. The determination results of two methods were basically consistent.