目的通过对GB/T 5750.5—2006《生活饮用水标准检验方法无机非金属指标》中硫酸盐的仲裁法———硫酸钡比浊法测定结果的不确定度评定,对该法作为仲裁法的适宜性进行评价。方法根据硫酸钡比浊法的测定方法,对测定过程中的所有不确定度分量进行评定,给出一水样测定结果的扩展不确定度。结果对一水样给出测量结果为250 mg/L,扩展不确定度为42 mg/L(k=2)。结论硫酸钡比浊法的测量结果不确定度过大,硫酸盐含量的可能分布区间为208~292 mg/L,对于卫生标准限值附近的硫酸盐含量不能准确测定,不适于作为生活饮用水中硫酸盐含量测定结果的仲裁法。对测定结果进行不确定度评定有助于选择适宜的仲裁检验方法。 Objective To assess the uncertainty of the results of determination of barium sulphate turbidimetry by the arbitration method of sulfate in GB / T 5750.5-2006 “Standard Test Method for Inorganic and Non-metallic Materials of Domestic Drinking Water” Suitability for evaluation. Methods Based on the determination of barium sulfate turbidimetric method, all the uncertainty components in the determination process were evaluated, and the extended uncertainty of the determination results of a water sample was given. Results The results for a water sample were given as 250 mg / L with an extended uncertainty of 42 mg / L (k = 2). Conclusion The uncertainty of the measurement results of barium sulfate turbidimetric method is too large. The possible distribution range of the sulfate content is 208 ~ 292 mg / L, which can not be accurately determined for the sulfate content near the sanitary standard limit, which is not suitable for drinking water Arbitration Method for Determination of Sulfate Content. Uncertainty assessment of measurement results help to choose the appropriate arbitration test method.