Interfacial tension was used to study the electrochemical properties of the interface between LiCl in water and tetraalkylammonium tetraphenylborate in 1,2-dichloroethane. The interfacial tension decrease with decreasing of the size of the cation of the organic supporting electrolyte on the order TBA(+) < THA(+) < THpA(+) < TOA(+). The decrease of interfacial tension is also observed at the electrocapillary maximum the potential of which (potential of zero charge) shift towards more positive values in the order TBA(+) > THA(+) > THpA(+) > TOA(+). This fact maybe an evidence that there is an increase of adsorption when the alkyl chain length of the organic cation is reduced. (C) 2004 Elsevier Ltd. All rights reserved.