Calibration of pH glass electrodes by direct strong acid/strong base titrations under dilute conditions Original Research Article

The calibration of an electrode assembly composed of a set of two glass electrodes and a reference electrode, using strong acid/strong base titrations, was performed with an automatic titration system, to which was connected an automatic electrode switcher, controlled by a personal computer. Analysis of the data by the Gran method or by derivative methods reveals that the acquisition of reliable calibration parameters depends on the indicator electrode, particularly so for diluted solutions (1.0 × 10−3 M) of the strong acid. These discrepancies are attributed to the time of operation of the glass electrodes, but are not a caveat to the use of calibrations with very dilute solutions of strong acid, a practice that must be followed in water mixed media.