Volume 46, Number 6 (November - December 2001)

Key words: undiluted liquids, gravitational convection, voltammetry, microelectrodes

The influence of the electrodes radius and the orientation of the microelectrode vs the gravitational field on the wave heights and steady-state currents for undiluted simple alcohols has been examined. Methanol, 1-propanol, 1-butanol and 1-pentanol have been selected for the examination. The dependencies obtained for the methanol have particular analytical imporatnce, since in the previous papers it has been shown that those steady-state currents strongly depended on the concentration of dissolved electroactive and electroinactive analytes. The gravitational convection becomes substantial for the microelectrode radius greater than 5 mm, therefore, in analytical flow applications, it may neccesary to make an extra calibration when the orientation of the electrode is changed. Gravitational convection is the result of the formation of a more dense (compared to the alcohol bulk) ionic microlayer at the electrode surface.