Microelectrodes mass transport regime

Classical experiments performed with microelectrodes derive from the mass transport regimes and include steady-state voltanunetry, fast scan cyclic voltammetry and... 

If microelectrodes (hemispherical or inlaid-disc types) are used, the mass transport rate due to radial diffusion to the electrode is enhanced so that the current contribution of chemical steps is decreased relative to the diffusive transport. This statement can be easily verified on any EQrrE sequence at a macroelectrode of radius a 100 /zni the diffusion-controlled two-electron wave is observed when two one-electron electrode processes occurs at the same potential. At microelectrodes in steady-state regime the time scale is too short for the overall reaction and the number of electrons measured on the limiting current gradually declines to unity with decreasing electrode radius. On the other hand, the change in the current as a function of the electrode radius can be used to determine the rate constants of involved chemical steps. 

It was around the same time that the first reports on microelectrode arrays appeared. Both experimental and theoretical works (3-27) have demonstrated the advantages of such electrode assemblies, which result from the specific mass transport of electroactive materials or diffusion regimes taking place at their interface. These include the following ... 

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