全自动间断化学分析仪测定生活饮用水中六价铬的不确定度评定

Uncertainty evaluation of determination of hexavalent chromium in drinking water by automatic discontinuous chemical analyzer

目的评定全自动间断化学分析仪测定生活饮用水中六价铬的不确定度。方法建立了全自动间断化学分析仪测定生活饮用水中六价铬的数学模型,并对不确定度的来源进行了分析和评估,获得了六价铬含量的测量不确定度。结果本方法的测量结果为0.232 mg/L,取包含因子k=2(95%置信概率),扩展不确定度U=0.003 mg/L。结论不确定度来源主要有标准溶液、标准溶液配制、标准曲线拟合、重复性测量和仪器引入的不确定度。其中标准物质的不确定度和标准曲线拟合的不确定度相对较大。本研究为全自动间断化学分析仪测定生活饮用水中六价铬的含量及进行不确定度评价提供了理论基础。

Objective To evaluate the uncertainty of the determination of hexavalent chromium in drinking water by automatic discontinuous chemical analyzer.Methods A mathematical model for the determination of hexavalent chromium in drinking water by auto discrete analyzer was established.The source of uncertainty was analyzed and evaluated,and the uncertainty of measurement of hexavalent chromium content was obtained.Results The measurement result of this method was 0.232 mg/L,the coverage factor was k=2(95% confidence probability),and the expanded uncertainty was U=0.003 mg/L.Conclusion The uncertainty is mainly caused by standard solutions,standard solution preparation,standard curve fitting,repeatability measurement and the instrument,and the main sources are standard solution and standard curve fitting.This study provides theoretical basis for using automatic discontinuous chemical analyzer determining exavalent chromium in drinking water and uncertainty evaluation.