This paper aims to understand the differences in the oxidation of ferrocene in several scenarios. The first scenario focuses the direct oxidation of ferrocene in an aqueous conventional support electrolyte and the second one is when ferrocene is directly placed in mineral oil, forming an oil phase and causing an oil/water interface. Additional experiments were also conducted in an emulsion, which was constituted by ferrocene in oil and mixed with conventional electrolytes and tetrabutylammonium chloride (TBAC). A Boron-Doped Diamond Electrode (BDD) was used as the working electrode. We observed an approximately 0.07 V shift when the ferrocene oxidation was conducted at the oil/water interface compared with the direct oxidation in the conventional aqueous phase. This potential shift was also calculated using the Density Functional Theory (DFT) as a theoretical tool. An additional comparison was conducted related to the interface and emulsions, finding that the ionic strength is the most determining factor in these types of electrochemical studies. Finally, Tafel plots indicated that the reaction mechanisms and reaction geometry are different when the electrode is placed at the interface versus directly in the aqueous phase. (C) 2016 Elsevier Ltd. All rights reserved.