This study describes the electrochemical behavior of the ionophore carboxylic "lasalocid A" at the water vertical bar 1,2-dichlorotehane interface. It was carried out by means of cyclic voltammetry and ac impedance spectroscopy. The cyclic voltammetry studies showed that this ionophore is able to facilitate transfer of divalent metal ions across a liquid vertical bar liquid interface, and the differential capacitance measured as a function of ionophore concentration shows that lasalocid is absorbed at the interface and that it breaks the charge stratification when it transfers the metal ion across the interface. The interfacial complexation of the heavy metal and the transport across biological membranes is probably a key question in the heavy metal accumulation in a biological cell. Therefore the liquid vertical bar liquid interface could be a good model to mimic the metal transfer across a hydrophobic environment. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.008212jes] All rights reserved.