Membrane Electrodes - Potentiometric Methods of Analysis

Membrane Electrodes

If metallic electrodes were the only useful class of indicator electrodes, poten- tiometry would be of limited applicability. The discovery, in 1906, that a thin glass membrane develops a potential, called a membrane potential, when oppo- site sides of the membrane are in contact with solutions of different pH led to the eventual development of a whole new class of indicator electrodes called ion- selective electrodes (ISEs). Following the discovery of the glass pH electrode, ion- selective electrodes have been developed for a wide range of ions. Membrane electrodes also have been developed that respond to the concentration of molecu- lar analytes by using a chemical reaction to generate an ion that can be monitored with an ion-selective electrode. The development of new membrane electrodes continues to be an active area of research.