This topic has been chosen from the book, Analytical Chemistry ", written by G. D. Christan and others. Topic: Potentiometric electrodes and potentiometry. Learning objectives: Types of electrodes and electrode potentials from the Nernst equation. Liquid junctions and junction potentials. Reference electrodes. Accuracy of potentiometric measurements. The pH glass electrodes. Standard buffers and the accuracy of pH measurements. The pH meter. Ion-selective electrodes. The selectivity coefficient.