TECHNICAL POSSIBILITIES OF METERS TO GUARANTEE COMPARABLE pH VALUES

摘要

The retraceability of a measurement is a basic requirement for the meaningfulness of a measured value. With pH measurements all measuring results are based on the pH values of a number of standard buffer solutions defined according to NBS/NIST. The pH values of the solutions are guaranteed by the proficient compounding of the solutions. In practice the user himself compounds the standard buffer solutions or uses ready solutions offered by different manufacturers. Apart from the standard buffer solutions, various Technical Buffer Solutions or other standard solutions are used, the pH values of which also refer to the defined standard solutions. The pH values of all non-primary buffer solutions have to be secured against standard buffer solutions by careful pH measurements.