原子荧光法测定地表水中砷的测量不确定度评定

Evaluation of Uncertainty of Measuring Arsenic in Surface Water by Atomic Fluorescence Spectrometry

识别测量过程中不确定的来源,分析各个分量的产生,计算合成标准不确定度,测得地表水样中砷的浓度为0.43 mg/L,扩展不确定度U95=0.01 mg/L(k=2)。结果表明,合成标准不确定度主要来自仪器分析过程,但样品前处理引入的不确定度的影响也不能低估。因此,在评定类似的化学分析的测量不确定度时,应充分考虑前处理过程的影响,优化实验步骤,减少该过程输入的不确定度分量。

Origins of uncertainty in the measuring process were identified,the production of each component was analyzed,and the combined standard uncertainty was calculated and reported as well.As is detected at a concentration of 0.43 mg/L in the surface water and 0.01 mg/L of the expanded uncertainty,U95（k=2）,is obtained in the method.The result indicates that the combined standard uncertainty mainly derives from instrument analysis,while the contribution from the uncertainty of pretreatment could not be underestimated.Therefore,the effect of pretreatment should be considered adequately and the experimental procedures can be optimized to decrease the contribution from the uncertainty of pretreatment while evaluating uncertainty in measurement of similar chemical analysis.