ULTRAMICROELECTRODES IN ELECTROCHEMISTRY

In the 1950s and 1960s fundamental developments in electrochemical met hods included voltammetry and low signal techniques. A generation late r, the discovery of the unusual properties of ultramicroelectrodes has opened new possibilities of analyzing electrode processes. The change s in mass transport conditions bring about extremely high current dens ities at ultramicroelectrodes, whereas the currents themselves become very small. This little-noticed phenomenon allows for many electroanal ytical applications that are not possible with conventional electrodes , especially experiments in solutions with very low electrolyte concen trations, in nonpolar solvents, in solids, and even in gases. In addit ion, two factors-changes in the experimental time scale at low scan ra tes because of the size of the electrode, and insignificant iR effects at very high scan rates-make it possible to study very fast homogeneo us and heterogeneous electrode processes.