STEPPED-POTENTIAL VOLTAMMETRIES AT STATIONARY ELECTRODES .1. DIFFERENTIAL STAIRCASE, DIFFERENTIAL-PULSE AND SQUARE-WAVE VOLTAMMETRIES

Differential pulse voltammetry (DPV) and related techniques are examin ed. The proposed treatment is valid for any pulse method performed at stationary plane or spherical electrodes in the case of simple reversi ble reactions with both redox forms soluble in solution. The behaviour of the waves in DPV depends on the ratio R of the duration of the imp ulses to the duration of the steps of the potential staircase on which the impulses, of amplitude \Delta E\, are added. The waves behave as in differential pulse polarography performed at a renewable mercury dr op electrode only if R > 0.8. Square-wave voltammetry, where R = 0.5, and differential staircase voltammetry, where Delta E = 0, appear as p articular cases of the DPV. All these methods can be analysed satisfac torily in a simple way.