测量不确定度评定改进方法探讨——以自配氨氮和EDTA标准溶液为例

On methods to improve the evaluation of measurement uncertainty——Taking self-prepared ammonia nitrogen and EDTA standard solution as an example

不确定度评定方法在中级及以下实验室中很难得到应用,尤其在数学建模方面存在较大难度。这类实验室很少报告测量不确定度,配制的标准溶液的标定数值往往仅为平均值。一些实验室在进行不确定度评定时,往往以偏微分各量的平方和之平方根的方式计算非完全独立不确定度分量。实际上,这种计算方式是错误的。基于全微分的不确定度数学模型已经建立起来了。以平方和的平方根作为不确定度独立分量的求和方式,对自配的氨氮和EDTA标准溶液开展不确定度评定。结果表明,该方法简洁、准确、实用,有利于不确定度评定方法的应用推广。

It is difficult to use uncertainty assessment methods in intermediate and lower-level laboratories,especially in mathematical modeling.These laboratories rarely report measurement uncertainty,and the calibration values of the prepared standard solutions are often only averaged.Some laboratories often calculate non completely independent uncertainty components in the form of the square root of the square sum of partial differential quantities when evaluating uncertainty.In fact,this calculation method is incorrect.Therefore,this paper establishes a mathematical model for uncertainty based on total differentiation and perform uncertainty evaluation on self-prepared ammonia nitrogen and EDTA standard solutions by summing the square root of as the independent component of uncertainty.The results indicate that this method is concise,accurate,practical and conducive to the application and promotion of uncertainty evaluation methods.