硝酸铵氧化滴定法测定锰铁中锰含量的不确定度评定

Evaluation of uncertainty in the determination of manganese in ferromanganese by ammonium nitrate oxidation titrimetry

通过分析影响硝酸铵氧化滴定法测定锰铁中锰含量不确定度的各种因素和评定各个不确定度分量,计算出合成标准不确定度,最终给出置信因子为2时的扩展不确定度。评定结果表明,样品测量重复性引入的不确定度对总不确定度的影响最大,其次是用标准物质标定硫酸亚铁铵标准滴定溶液、滴定时消耗硫酸亚铁铵标准滴定溶液体积和称量引入的不确定度。因此为了保证测量结果的准确性和可靠性,应通过规范实验人员操作来降低随机误差对测量不确定度的影响。

By analyzing the factors that affect the uncertainty in the determination of manganese in ferromanganese by ammonium nitrate oxidation titrimetry and evaluating each uncertainty component,the combined standard uncertainty was worked out,and the expanded uncertainty was obtained with the confidence coefficient of 2.The results showed that the uncertainty caused by sample measurement repeatability had greatest influence on total uncertainty.The uncertainties,including that introduced by the calibration of ammonium ferrous sulfate standard titration solution by certified reference materials,the volume consumption of ammonium ferrous sulfate standard titration solution during titration and the process of weighing,also had great influence.Therefore,in order to guarantee the accuracy and reliability of results,the operation of experimenters should be specified to reduce the influence of random error on determination uncertainty.