三酸消解-电感耦合等离子体质谱仪测定土壤中全钼的不确定度分析

Uncertainty analysis for determination of total molybdenum in soil by triacid digestion and inductively coupled plasma mass spectrometer

目的通过对土壤中全钼不确定度的评定和分析,寻求更优的条件以及方法来提高测量的准确性及可靠性。方法本文采用三酸消解电感耦合等离子体质谱仪法测定土壤中全钼含量。结果方法检出限达0.011 mg/kg,对于所测元素校准曲线相关系数R为0.9999,回收率在97.8%-105.6%,方法精密度为2.49%,本方法测定土壤中全钼含量的扩展不确定度为(0.660±0.03)mg/kg(K=2)。结论通过分析影响测量不确定度的主要来源,对测定全过程的重复性、曲线拟合、标准溶液、样品定容体积、样品称量、玻璃量具及样品消解过程影响不确定度的因素进行分析,首先,应严格控制样品消解过程中的各种条件,如消解温度、消解时间等,以减少样品损失;其次,可以采用微波消解、高压消解等技术来优化前处理方式,以提高测量结果的准确性和可靠性。

Objective To find better conditions and methods to improve the accuracy and reliability of the measurement by evaluating and analyzing the total molybdenum uncertainty in soil.Methods The content of total molybdenum in soil was determined by inductively coupled plasma mass spectrometer with three acid digestion.Results The detection limit of the method was 0.011 mg/kg,the correlation coefficient R of the calibration curve was 0.9999,the recovery was 97.8%-105.6%,and the precision of the method was 2.49%.The extended uncertainty of the method for the determination of total molybdenum content in soil was(0.660±0.03)mg/kg(K=2).Conclusion By analyzing the main sources affecting the uncertainty of measurement,the factors affecting the uncertainty of the whole process of determination,such as repeatability,curve fitting,standard solution,sample constant volume,sample weighing,glass measuring tools and sample digestion process were analyzed.Firstly,various conditions during the digestion process,such as digestion temperature and digestion time,should be strictly controlled to reduce the sample loss.Secondly,microwave digestion,high pressure digestion and other technologies can be used to optimize the pre-treatment mode to improve the accuracy and reliability of the measurement results.