全国实验室生活饮用水中硝酸盐氮测定的能力验证研究

目的通过能力验证计划,对全国实验室的生活饮用水中硝酸盐氮含量检测能力进行分析和评价。方法能力验证计划中使用的被测样品参考二级标准物质制备方法制备,采用单因子方差分析法和t检验法分别对其进行均匀性检验和稳定性检验。将全国多个行业系统所属的608家实验室提交的结果进行迭代稳健统计分析,采用Z比分数评定各参加实验室的测试结果。结果获得满意结果的实验室541家,结果满意率为89.0%;可疑结果的有20家,结果可疑率为3.3%;离群结果的有47家,结果离群率为7.7%。结论能力验证统计结果表明,国内实验室的生活饮用水中硝酸盐氮检测能力总体较好,少部分实验室的检测能力有待改进提高。

Proficiency testing for determination of nitrate nitrogen in drinking water among laboratories in China

Objective To evaluate the capacity of national laboratories for determination of nitrate nitrogen in drinking water using Proficiency Testing Program.Methods The preparation methods of the Secondary Standard Materials were used as the reference for the sample preparation in this Proficiency Testing Program.The homogeneity and stability of the samples were tested by Single Factor Analysis of Variance (ANOVA) and T-test.The results provided by 608 participating laboratories from multiple trade were analyzed by robust statistics and assessed using the Z-score.Results A total of 541 laboratories,or 89.0％ of total participating laboratories,obtained satisfactory results.Results provided by 20 laboratoties,or 3.3％ of total participating laboratories,were found to suggest doubts in their capacities.Finally,there were 47 laboratories,constituting 7.7％ of total participating laboratories,with results that were found to be outliers.Conclusion The capacity of national laboratories for determination of nitrate nitrogen in drinking water has been ranked as satisfactory according to statistical analysis of the Proficiency Testing Program results.Only a small portion of the participants require further improvement in their capacities.