邻二氮杂菲分光光度法测定镁合金中铁含量测量结果的不确定度评定

Analysis of the Uncertainty for the Determination of Iron in Magnesium Alloy by Orthopenanthroline Spectrophotometry

对邻二氮杂菲分光光度法测定镁合金中铁含量的不确定度来源进行了辨别,并在此基础上对测定过程中的不确定度分量进行了合理评定。测量不确定度主要来源于试样称量、标准溶液配制、校准曲线拟合、各种玻璃量器的使用及测量重复性。依据不确定度评定的步骤,分析和计算得到了各分量标准不确定度及合成标准不确定度,最后合成标准不确定度乘以95%置信概率下的扩展因子2获得测量结果的扩展不确定度。

The source of measurement uncertainty was discussed for the determination of iron in magnesium alloy by orthopenanthroline spectrophotometry.The components of measurement uncertainty were then evaluated correctly. The measurement uncertainty mainly derived from the mass of sample,the preparation of standard solution,the fitting of calibration curve,the application of glass containers and the repeatability of measurements.Based on the evaluation procedure of uncertainty,the standard uncertainty of each component and combined standard uncertainty were analyzed and calculated.Finally, the expanded uncertainty was obtained via multiplying the combined standard uncertainty by 2 which was the expansion factor at 95% confidence level.