The electrochemical behavior for pure platinum microelectrode and its alloys (Pt-Ir (20%, m/m); Pt-Rh (10%, m/m)) microelectrodes were studied in aqueous solution containing 6.00 x 10-3 mol L-1 [K4Fe(CN)6] + 1 mol L-1 KCl. The electrodes were prepared as flat microdisc with r e = 30 to 150 mm. The true steady state condition was not obtained for any of the microelectrodes used. The near-steady state equations were used in all experiments and the average curve represents the steady state current up to the first half part of the I/E curve for microelectrodes with r e 70 mm, which represents a kind of transition dimension from microelectrode to semi-microelectrode. In spite of these observations, the mathematical equations normaly used to evaluate the linear and radial diffusion contribution to the total current of a cyclic voltammogram showed a good agreement with experimental results for all microelectrodes used in this work.
Microelectrodes; cyclic voltammetry; near-steady state condition
