Adsorption of charged species at the interface between two immiscible electrolyte solutions (ITIES) is simulated taking into account both the mutual influence between the potential dependent surface excess charge and the potential distribution between the two phases and the partition equilibrium of the surface- active molecules. The electrical potential profiles are calculated assuming a single adsorption plane separating two electrical diffuse layers following the modified Verwey–Niessen model (MVN). The interfacial boundary potential is obtained from the electroneutrality condition. The interplay between adsorption and partition under steady-state conditions is addressed yielding voltammetric responses for the adsorption–desorption processes along with the faradaic response.