水中高锰酸盐指数测定不确定度的评定

摘要

合理评定测量结果的不确定度是分析实验室必须重视的问题。通过酸性高锰酸钾氧化法测定水中高锰酸盐指数的实例,确立高锰酸盐指数测量的不确定度数学模型。讨论了高锰酸盐指数测定值不确定度的各种因素,对各不确定度分量进行分析和量化,求得其扩展不确定度。结果表明,影响其测量不确定度的主要因素是测量熏复性。在高锰酸盐指数值为4.17 mg/L的水样测定中,扩展不确定度为0.08 mg/L。%The reasonable evaluation of uncertainty in measurement results is a matter of especial importance for assay laboratory.Through the example of determination permanganate index in water by acidic potassium permanganate method,the mathematical model of uncertainty is established.Based on analysis and quantification of the factors influencing the uncertainty in measurement result of permanganate index in water,the expanded uncertainty is calculated.The result shows that repeatability of testing is the key factor affecting the uncertainty.When the permanganate index is 4.17mg/L,the expanded uncertainty is 0.08mg/L.