Boron-doped diamond (BDD) has been extensively studied by their ability to oxidize a wide range of contaminants in liquid mixtures. These electrodes have a wide potential window margin for water discharge and stability for extended periods of time (1,2). However their electrochemical activity depends on the surface composition and the degree of crystallinity. On the other hand, electrochemical oxidation techniques have received great importance in the electrochemical desulfurization of organic sulfur compounds (3,4). In the present work electrochemical oxidation of DBT and 4,6-DMDBT was studed using BDD electrode in acetonitrile-water medium (electrolyte). Also was studied the oxidation of above compounds mentioned on the preoxygenated diamond surface by VMC, Chronoamperometry and electrolysis at constant potentials. The results showed that the oxygenated species on the surface of the BDD electrode influence the electrode-analyte interactions, the kinetics and the mechanism of the oxidation process. The analysis of the extracts after the electrochemical oxidation of DBT and 4,6-DMDBT by GC / MS and HPLC-MS / MS showed that the oxidation is selective. At potentials lower than 1.75V, the main product is the formation of sulfoxide, while at potentials greater than 1.75V it is the corresponding sulfone. A mixture of sulfoxide, sulfone and other oxidation products was obtained due to the opening of the aromatic ring for potentials greater than 2.0 V and prolonged electrolysis times.

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