两种干扰校正方式下电感耦合等离子体原子发射光谱法测定钼铝合金中硅的方法比较

采用电感耦合等离子体原子发射光谱法(ICP-AES)测定钼铝合金中硅时,选择Si 288.158 nm为分析谱线,此时基体钼的特征谱线Mo 288.137 nm会对Si 288.158 nm产生光谱干扰,而基体空白扣除与多谱线拟合(MSF)两种干扰校正方式均可校正钼基体产生的干扰。通过比较基体空白扣除与MSF两种干扰校正方式下对应检测方法的校准曲线线性方程和线性相关系数、灵敏度、定量限、精密度和正确度等方法性能指标,分析了两种干扰校正方式校正干扰的效果。结果表明:基体空白扣除和MSF两种干扰校正方式下测定方法的校准曲线斜率和灵敏度基本一致,MSF校正下的校准曲线线性相关系数明显优于基体空白扣除校正;两种校正方式下方法的定量限分别为0.12 μg/mL和0.079 μg/mL,可见MSF校正下方法定量限更优。对硅质量分数分别为0.023%、0.063%、0.136%、0.264%和0.454%的5个钼铝合金样品中硅进行测定,其中基体空白扣除校正下测定结果的相对标准偏差(RSD)在0.62%~1.9%之间,加标回收率在90%~104%之间;MSF校正下测定结果的相对标准偏差在0.55%~1.3%之间,加标回收率在95%~103%之间。多谱线拟合校正下检测方法的精密度和正确度指标均优于基体空白扣除法。

Comparison of inductively coupled plasma atomic emission spectrometry for determination of silicon in molybdenum-aluminum alloy with two interference correction methods

During the determination of silicon in molybdenum-aluminum alloy by inductively coupled plasma atomic emission spectrometry (ICP-AES), Si 288.158 nm was selected as the analytical line. At this time, the characteristic spectral line of matrix molybdenum (Mo 288.137 nm) would cause spectral interference with Si 288.158 nm. Both matrix blank subtraction and multi-spectral fitting (MSF) could correct the interference caused by matrix molybdenum. The effect of two interference correction modes were analyzed by comparing the method property indexes, including the linear equation of calibration curve, linear correlation coefficient, sensitivity, limit of quantification, precision, and accuracy. The results showed that the slope and sensitivity of calibration curve were basically the same when the two interference correction modes of matrix blank subtraction and MSF were used. The linear correlation coefficient of calibration curve with MSF correction was obviously better than that of matrix blank subtraction correction. The limit of quantification of two methods was 0.12 μg/mL and 0.079 μg/mL, respectively, implying that the limit of quantification with MSF correction mode was better. The contents of silicon in five molybdenum-aluminum alloy samples with silicon mass fraction of 0.023%, 0.063%, 0.136%, 0.264% and 0.454% were determined. For the correction mode of matrix blank subtraction, the relative standard deviations (RSDs) were between 0.62% and 1.9%, and the recoveries were between 90% and 104%. For the correction mode of MSF method, the RSDs were between 0.55% and 1.3%, and the recoveries were between 95% and 103%. Therefore, the determination method with MSF correction exhibited better precision and accuracy compared to the matrix blank subtraction mode.