水中COD测量不确定度的评定

Evaluating the Uncertainty Determination of Chemical Oxygen Detection in Water Sample by Titration

建立了水中COD测定的不确定度模型,并给出了各不确定度分量的灵敏度系数。从模型可见影响COD测量不确定度值的主要因素来自于硫酸亚铁铵浓度、水样滴定消耗硫酸亚铁铵、空白滴定消耗硫酸亚铁铵和水样移取等引进的不确定度分量。计算了各不确定度分量值并给出了扩展不确定度。

In this paper we create a model to evaluate the uncertainty in determination of chemical oxygen demand in water sample by titration,and give sensitivity coefficient of each uncertainty component.It appears that the final value of COD is directly from the uncertainty components which include (NH_4)_2Fe(SO_4)_2 concentration,titration of sample against (NH_4)_2Fe(SO_4)_2 (V_1),titration of blank against (NH_4)_2Fe(SO_4)_2 (V_0) and transfer volume of sample.We calculate each uncertainty and give the expanded uncertainty.