ULTRAMICROELECTRODES IN ELECTROCHEMISTRY

In the 1950s and 1960s fundamental developments in electrochemical methods included voltammetry and low signal techniques. A generation later, the discovery of the unusual properties of ultramicroelectrodes has opened new possibilities of analyzing electrode processes. The changes in mass transport conditions bring about extremely high current densities at ultramicroelectrodes, whereas the currents themselves become very small. This little‐noticed phenomenon allows for many electroanalytical applications that are not possible with conventional electrodes, especially experiments in solutions with very low electrolyte concentrations, in nonpolar solvents, in solids, and even in gases. In addition, two factors— changes in the experimental time scale at low scan rates because of the size of the electrode, and insignificant iR effects at very high scan rates—make it possible to study very fast homogeneous and heterogeneous electrode processes. Copyright © 1993 by VCH Verlagsgesellschaft mbH, Germany