电感耦合等离子体质谱法测定钢中痕量酸溶铝

采用硝酸溶解样品,建立了电感耦合等离子体质谱法(ICP-MS)测定钢中痕量酸溶铝(Als)的方法,并对其测定条件进行了优化。实验表明:采用纯化后硝酸溶解样品可以降低对检测结果的影响;高纯铁基体效应对测定的影响不可忽略,故采用待测样品作为基体的标准加入法绘制校准曲线以消除该影响;采用石英烧杯进行样品溶解,测定结果比玻璃烧杯更稳定;采用塑料容量瓶对硅钢标准样品溶液定容,测定结果相对于玻璃容量瓶更接近认定值;对样品前处理的条件进行了优化,最终选择硝酸用量为5mL,溶解时间为10min;选择⁴⁵Sc作为内标对硅钢标准样品进行测定,结果较选用⁸⁹Y为内标更接近认定值;采用2%(体积分数)硝酸冲洗管路8s,可基本消除记忆效应。以²⁷Al质量浓度为横坐标,²⁷Al与内标元素响应值的比值为纵坐标绘制标准加入法校准曲线,校准曲线方程的相关系数为0.9998;方法对样品的测定下限为0.00006%。采用实验方法对5个钢标准样品和2个合金钢实际样品进行测定,测定值与认定值基本一致,相对标准偏差(RSD,n=5)在1.6%~4.5%之间。

Determination of trace acid soluble aluminium in steel by inductivelycoupled plasma mass spectrometry

The sample was dissolved with nitric acid. A determination method of trace acid soluble aluminum (Als) in steel by inductively coupled plasma mass spectrometry (ICP-MS) was established. The determination conditions were also optimized. The experiment showed that the use of purified nitric acid to dissolve sample could reduce the influence on determination results. The matrix effect of high-purity iron could not be ignored, so the calibration curve was prepared by standard addition method with testing sample as matrix to eliminate this effect. The sample was dissolved in quartz beaker, and the determination results were more stable than those conducted in glass beaker. The sample solution of silicon steel certified reference material was diluted to constant volume in plastic volumetric flask, and the determination result was closer to the certified value than that in glass volumetric flask. The sample pretreatment conditions were optimized: the amount of nitric acid was 5mL and the dissolution time was 10min. The determination results of silicon steel certified reference material with ⁴⁵Sc as internal standard was closer to the certified value than that with ⁸⁹Y. When the pipe was washed with 2% (volume fraction) nitric acid for 8s, the memory effect could be basically eliminated. The mass concentration of ²⁷Al was used as x-axis, while the response ratio of ²⁷Al to internal standard element was used as y-axis to prepare calibration curve by standard addition method. The correlation coefficient of calibration curve equation was 0.9998. The low limit of determination for the method was 0.00006%. The proposed method was applied for determination of five certified reference materials of steel and two actual samples of alloy steel. The results were basically consistent with the certified values. The relative standard deviations (RSD, n=5) were between 1.6% and 4.5%.