In this work, the development and optimization of a secondary method for pH measurement using a differential potentiometric cell are described. The method was optimized and validated by measurement of three certified primary buffer solutions (CRMs) with nominal pH values of 4.005, 6.865 and 9.180 at 25 °C. The method was applied to assess homogeneity and stability of phosphate buffer solution with nominal pH of 7.000 at 25 °C which will be used as test item in proficiency testing schemes for pH measurement of testing laboratories. The experiments carried out and described in this article proved that this particular design of secondary differential potentiometric cell requires small volume of solutions, is fast, accurate and precise and is suitable for the characterization of secondary buffer solutions and assessment of homogeneity and stability of buffer solutions.

在这项工作中，描述了使用差分电位计进行pH测量的辅助方法的开发和优化。通过在25°C下测量标称pH值为4.005、6.865和9.180的三种认证的一级缓冲溶液（CRM），对该方法进行了优化和验证。该方法用于评估标称pH为7.000的磷酸盐缓冲溶液在25°C下的均匀性和稳定性，该溶液将在测试实验室的pH测量能力验证计划中用作测试项目。本文进行并描述的实验证明，这种次级差分电位计单元的特殊设计需要小体积的溶液，快速，