摘要
目的探讨检验过程中不同因素对连续流动分析仪测定饮用水中高锰酸盐指数检测结果的影响,评定该法的不确定度。方法依据《测量不确定度要求的实施指南》CNAS-GL05:2011、《测量不确定度评定与表示》JJF 1059.1-2012及实际检测过程,建立数学模型,确定实验过程中不确定度的来源,对标准贮备液的配制、标准曲线的绘制和拟合、实验重复性、测量仪器以及样品加标回收6个分量进行评定。结果本次实验测得饮用水中高锰酸盐指数的含量Cx=(1.17±0.03)mg/L,标准合成不确定度为1.200%,取置信水平P=95%,k=2,则扩展不确定度Ux=0.03 mg/L,其中6个分量的不确定度分别为0.02%,0.23%,1.10%,0.30%,0.17%和0.21%。结论标准曲线拟合引入的不确定度贡献最大,在实验过程中,应当特别注意;测量重复性对总不确定度的贡献次之,在评定不确定度时,应尽可能进行重复性实验。
Objective To discuss the impact of different factors on permanganate index measured by continuous flow analyzer in drinking water and evaluate the uncertainty of this method. Methods According to Application Guidance of Requirements for Measurement Uncertainty（CNAS-GL05：2011） and Evaluation and Expression of Uncertainty in Measurement（JJF 1059.1-2012） and actual detection process, the mathematical model was established. The preparation of standard stock solution, standard curve drawing and fitting, experimental repeatability, measuring instrument and standard added recovery were determined as the sources of uncertainty of measurement to be evaluated. Results In the measurement, the permanganate index in drinking water was Cx=（1.17±0.03）mg/L, with the combined standard uncertainty of 1.20%. If the confidence level P=95% and k=2, the expanded uncertainty was Ux=0.03 mg/L. The uncertainty of the six components mentioned above was 0.02%, 0.23%, 1.10%, 0.30%, 0.17% and 0.21%, respectively. Conclusions In the measurement, the maximum contribution to uncertainty is caused by standard curve fitting and should be paid more attention to. The experimental repeatability takes the second place to the uncertainty and the repetitive measurement should be conducted as more as possible in the uncertainty evaluating.
出处
《疾病预防控制通报》
2017年第6期74-76,82,共4页
Bulletin of Disease Control & Prevention(China)
