An interlaboratory comparison exercise was performed to assess the technical proficiency of laboratories in measuring the organochlorine pesticides in drinking water. The homogeneity and stability of the samples to be used in the test were evaluated, the assigned value and the standard deviation were determined according to ISO Guide 35 and ISO standard 17043, and the results showed that the samples were homogeneous and stable for the study period. The test samples (previously verified, as pesticide-free) and the fortifying solution were distributed to nine laboratories in Mexico and analyzed using their own established analytical methods. The pesticides in the fortifying solution were aldrin, β-endosulfan, heptachlor, lindane (γ-HCH), and p,p′-DDE. The assigned values and reference standard deviations were compared with those obtained by each laboratory to determine the z-score for each pesticide and laboratory, and the results are shown graphically for each pesticide. The acceptable z-scores obtained by the participating laboratories were 20 %, 20 %, 20 %, 40 %, and 16.7 % for aldrin, β-endosulfan, heptachlor, lindane, and p,p′-DDE, respectively. This study also provides a summary of the sample preparation and chromatographic techniques used by the participating laboratories, which highlights the technical problems revealed by the interlaboratory exercise.

中文翻译：

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饮用水中有机氯农药的测定：墨西哥实验室技术能力测试

进行了实验室间比较练习，以评估实验室在测量饮用水中有机氯农药方面的技术熟练程度。对用于试验的样品的均匀性和稳定性进行了评价，根据 ISO Guide 35 和 ISO 标准 17043 确定了指定值和标准偏差，结果表明样品在研究期内均质稳定. 测试样品（之前经过验证，不含农药）和强化溶液被分发到墨西哥的九个实验室，并使用他们自己建立的分析方法进行分析。强化溶液中的农药为艾氏剂、β-硫丹、七氯、林丹 (γ-HCH) 和 p,p'-DDE。将指定值和参考标准偏差与每个实验室获得的值进行比较，以确定每种农药和实验室的 z 值，并以图形方式显示每种农药的结果。参与实验室获得的可接受的 z 分数分别为艾氏剂、β-硫丹、七氯、林丹和 p,p'-DDE 的 20%、20%、20%、40% 和 16.7%。本研究还总结了参与实验室使用的样品制备和色谱技术，突出了实验室间活动揭示的技术问题。艾氏剂、β-硫丹、七氯、林丹和 p,p'-DDE 分别为 7%。本研究还总结了参与实验室使用的样品制备和色谱技术，突出了实验室间活动揭示的技术问题。艾氏剂、β-硫丹、七氯、林丹和 p,p'-DDE 分别为 7%。本研究还总结了参与实验室使用的样品制备和色谱技术，突出了实验室间活动揭示的技术问题。