离子色谱法测定饮用水中高氯酸盐不确定度评定

Evaluation of uncertainty in the determination of perchlorate in drinking water by ion chromatography

高氯酸盐是饮用水中新型的污染物,危害人体健康,新颁布的《生活饮用水卫生标准》(GB 5749-2022)已列为扩展指标。通过评定离子色谱法测定饮用水中高氯酸盐的不确定度,确定影响结果准确性的因素。以《生活饮用水标准检验方法第5部分:无机非金属指标》(GB/T 5750.5-2023)为依据,采用离子色谱法测定饮用水中高氯酸盐,并对引入各步骤的不确定程度进行分析和计算。并评估其扩展不确定度。经测定水中高氯酸盐含量为0.101 mg/L,扩展不确定度为0.005 mg/L(k=2)。测量不确定度主要从六个方面引入,分别是标准物质本身、标准使用液配制、系列标准工作液配制、试样重复性测定、加标回收率及主要设备。其中对总不确定度影响最大的为标准系列工作液配制过程引入的不确定度。

Based Perchlorate is a new type of pollutant in drinking water,which is harmful to human health.The newly promulgated“Standards for Drinking Water Quality”(GB 5749-2022)has been listed as an expanded indicator.The uncertainty of determination of perchlorate in drinking water by ion chromatography was evaluated,and the factors affecting the accuracy of the result were determined.On the Standard Test Method for Drinking Water Part 5:Inorganic Nonmetallic Indicators(GB/T 5750.5-2023),the perchlorate in drinking water was measured by ion chromatography,and the uncertainty introduced in each step was analyzed and calculated.And evaluate its expanded uncertainty.The perchlorate concentration in drinking water was 0.101 mg/L and the extended uncertainty was 0.005 mg/L(k=2).The measurement uncertainty is mainly introduced from six aspects,namely,the standard material itself,the preparation of standard working fluids,the preparation of series of standard working fluids,the determination of sample repeatability,the recovery rate and the main equipment.The most important factor affecting the total uncertainty is the uncertainty introduced in the preparation process of standard series working fluids.