Potentiometric Method of pH Measurement:

The pH is determined by measurement of the emf of a cell comprising an indicator electrode (an electrode responsive to hydrogen ions such as glass electrode) immersed in the test solution and a reference electrode (usually a saturated calomel electrode, SCE) contact between the test solution and the reference electrode is achieved by means of liquid-junction, that form the elements of a reference electrode. The emf of this cell is measured along with pH. Thus procedure for stepwise calibration of pH meter and measurement of pH of a test sample.