对氨基二甲基苯胺比色法测定的地下水中硫化物 不确定度的评定

采用不确定度连续传递模型对对氨基二甲基苯胺分光光度法测定的地下水中硫化物的不确定度进行了评定，在标准曲线拟合这一关键步骤上采用双误差曲线拟合，并与最小二乘法的拟合结果进行比较。结果表明，对于含较高浓度硫化物的水样，由双误差拟合出来的结果比最小二乘法拟合的结果更为准确。在采用双误差曲线拟合对实际样品进行定量时，应选择合适浓度范围内的标准曲线，使测定浓度落在标准曲线的较高浓度部分，使结果更为准确、合理。

Uncertainty evaluation for the determination of sulfides in groundwater samples by para-amino aniline photometric method

The measurement uncertainty of the analytical results of sulfides in groundwater samples by para-amino aniline photometric method was evaluated using continuous propagation model of uncertainty. At the key step of standard curve fitting, the authors adopted the double-error curve fitting in comparison with the least square method. The results show that, for the higher concentration samples, the results of double-error curve fitting are more accurate, and when double-error curve fitting is adopted to quantify the actual samples, the appropriate concentration range of standard curve should be selected, in which the concentration of the samples falls into the range of higher concentration, so that the results are more accurate and reasonable.