生活饮用水中镉检测的实验室间比对

Interlaboratory comparison for determination of cadmium in drinking water

目的 通过实验室间比对项目的实施,对省市级疾病预防控制中心实验室生活饮用水中镉的检测能力进行分析和评价。方法 实验室间比对项目中使用的比对样品参考二级标准物质制备方法制备,分别采用单因子方差分析法(F检验法)、线性拟合趋势分析法、平均值一致性检验法(t检验法)对其进行均匀性检验、稳定性检验及模拟运输短期稳定性检验。在采用核密度图法检验实验室检测结果分布情况基础上,采用配制值和方法精密度分别确定指定值和能力评定标准差,对实验室检测结果进行统计分析,采用Z值评定各参加实验室的检测能力。结果 共31个省(自治区、直辖市)409家实验室参加该项实验室间比对项目,获得满意结果的实验室383家(93.6%),可疑结果有4家(1.0%),离群结果有22家(5.4%)。结论 409家省市级疾病预防控制中心实验室生活饮用水中镉检测能力总体较好,少部分实验室的检测能力有待改进提高。

OBJECTIVE To analyze and evaluate the testing capability of cadmium in drinking water in the laboratories of the provincial and municipal centers for disease control and prevention across the country by implementing the interlaboratory comparison project.METHODS The preparation method of the secondary standard materials were used as the reference for the sample preparation in the interlaboratory comparison project. The homogeneity and stability of the samples and short-term stability for simulated transportation were tested by single factor analysis of variance(ANOVA) and linear regression and mean consistency test(t test). On top of using the kernel density estimation to test the distribution of laboratory test result, we adopted precision statistical method to analyze the laboratory test result and used Z-score to evaluate the testing ability of each participating laboratory.RESULTS A total of 409 laboratories throughout the country participated in the proficiency testing program. 383 laboratories(93.6%) of participating laboratories, obtained satisfactory result.Results provided by 4 laboratories(1.0%) of total participating laboratories, were found suspicious in their capacities. Finally, there were 22 laboratories(5.4%) of total participating laboratories, with result found to be outliers.CONCLUSION The statistical result of the interlaboratory comparison project show that the testing capability of cadmium in drinking water has been ranked as satisfactory in the laboratories of the provincial and municipal centers for disease control and prevention across the country, and the testing capability of a small number of laboratories requires further improvement.