The effect of boron doped diamond (BDD) surface termination, immediately after cathodic and anodic electrochemical pre-treatments, on the electrochemical response of a BDD electrode in aqueous media and the influence of the different supporting electrolytes utilized in these pre-treatments on the final surface termination was investigated with [Fe(CN)(6)](4-/3-), as redox probe, by cyclic and differential pulse voltammetry and electrochemical impedance spectroscopy The cyclic voltammetry results indicate that the electrochemical behavior for the redox couple [Fe(CN)(6)](4-/3-) is very dependent on the state of the BDD surface, and a reversible response was observed after the cathodic electrochemical pre-treatment. whereas a quasi-reversible response occurred after anodic electrochemical pre-treatment. Differential pulse voltammetry in acetate buffer also showed that the potential window is very much influenced by the electrochemical pre-treatment of the BDD surface. Electroactivity of non-diamond carbon surface species (sp(2) inclusions) incorporated into the diamond structure was observed after cathodic and anodic pre-treatments Electrochemical impedance spectroscopy confirmed the cyclic voltammetry results and indicates that the BDD surface resistance and capacitance vary significantly with the electrolyte and with the electrochemical pre-treatment. caused by different surface terminations of the BDD electrode surface (C) 2010 Elsevier Ltd All rights reserved.