This work presents the results from stability studies for several electrolytic conductivity (EC) reference materials submitted to repeated use conditions, as required by the last version of the ISO 17034 standard. Eight batches of reference materials, composed of water or water/ n -propanol and HCl or KCl (at different concentrations), were studied, with nominal EC values ranging from 5 to 12,825 µS·cm −1 . The materials were submitted to a simulation of repeated use, with the manipulation of bottles once a week and their storage under refrigeration with air gaps inside them. They were then analyzed once a month by the EC primary measurement method. The measurement results were evaluated to check for deviations from conventional long-term stability monitoring and for variation trends using normalized error and linear regression statistical tests. The results indicated that the repeated use simulation caused deviations in the EC for the 100 and 500 µS·cm −1 reference materials and variation trends in the EC for the 5000 and 12,825 µS·cm −1 reference materials. From the results, the uncertainty related to stability monitoring under repeated use conditions was calculated for each reference material.

中文翻译：

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通过初级测量方法在重复使用条件下对电解电导率标准物质的稳定性监测

这项工作展示了根据 ISO 17034 标准的最新版本的要求，在重复使用条件下提交的几种电解电导率 (EC) 参考材料的稳定性研究结果。研究了八批由水或水/正丙醇和 HCl 或 KCl（不同浓度）组成的参考材料，其标称 EC 值范围为 5 至 12,825 µS·cm -1 。这些材料进行了重复使用的模拟，每周对瓶子进行一次操作，并在冷藏条件下储存，内部有空气间隙。然后通过 EC 主要测量方法每月对其进行一次分析。使用归一化误差和线性回归统计测试对测量结果进行评估，以检查与常规长期稳定性监测的偏差和变化趋势。结果表明，重复使用模拟导致 100 和 500 µS·cm -1 参考材料的 EC 偏差以及 5000 和 12,825 µS·cm -1 参考材料的 EC 变化趋势。根据结果​​，计算了每种参考物质在重复使用条件下与稳定性监测相关的不确定度。