酸性高锰酸钾滴定法测定生活饮用水中耗氧量的不确定度评估

Acidic potassium permanganate titration of oxygen consumption in drinking water assessment of uncertainty

目的建立酸性高锰酸钾滴定法测定生活饮用水中耗氧量的不确定度分析方法,找出其主要影响因素。方法建立不确定度的数学模型,系统分析计算不确定度的各个分量[1]。结果按GB/T5750.7-2006(1.1)酸性高锰酸钾滴定法测定生活饮用水中的耗氧量,当结果为0.88 mg/L时,其扩展不确定度为0.05μg/L(k=2)。结论把握好样品测量过程中的主要环节,严格控制恒温时间和终点偏倚,以及保证测量重现性良好是降低测量不确定度的关键。

Objective To establish acidic potassium permanganate titration of oxygen consumption in drinking water uncertainty analysis methods to identify the main factors.Methods A mathematical model of uncertainty,system analysis and calculation of the various components of uncertainty[1].Results According to GB/T5750.7-2006（1.1） acidic potassium permanganate titration of oxygen consumption in drinking water,when the result is 0.88 mg/L,its expanded uncertainty of 0.05 μg/L（k=2）.Conclusion a good grasp of the sample measurement process in key areas,strict control of temperature and end time bias,and to ensure good reproducibility of measurement is the key to reduce the measurement uncertainty.