Standard Reference Materials: Standardization of pH Measurements (1988 Edition)

摘要

One of the most widely performed analytical measurements in chemical laboratories is that of pH using the glass electrode. In order to ensure the consistency of these measurements, the National Bureau of Standards has recommended an operational scale of pH, maintained in terms of the pH(S) of a series of standard solutions. Certified samples of buffer materials, from which the standard reference solutions of reproducible pH can be prepared, as well as solutions in the case of rainwater, are issued by the National Bureau of Standards as Standard Reference Materials. The report is concerned primarily with a discussion of the method used at NBS for the assignment of pH(S) values to these standard solutions, a description of the NBS measurement facilities for pH, and a summary of the characteristics of the buffer materials. A brief discussion of the types of electrodes used and the calibration of pH instrumentation is also presented.