1 This paper is in press for publication in Electrochemical Acta Electrochemical behaviour of gamma hydroxybutyric acid (GHB) at a platinum electrode in acidic medium R. Jiménez-Pérez b , J.M. Sevilla b , T. Pineda b , M. Blázquez b , J. González-Rodriguez *a a School of Life Sciences, Faculty of Science, University of Lincoln, Brayford Pool, Lincoln, LN67TS, UK b Departamento de Química Física y Termodinámica Aplicada, Universidad de Córdoba, Campus de Rabanales, Ed. Marie Curie, E-14071 Córdoba, España. Abstract. Gamma Hydroxybutyric Acid (GHB), when studied in a platinum electrode using cyclic voltammetry, presented three oxidation peaks in acid solutions that correspond to the oxidation of the alcohol group to the corresponding aldehyde and carboxylic acid (succinic acid). An anodic scan of GHB yielded two characteristic waves, which indicates an oxidation process dependent on the chemical environment on the surface of the electrode. The cathodic scan presented an inverted oxidation peak with an onset partially overlapping with the tail of the cathodic peak for the reduction of the platinum oxide formed initially during the anodic scan. This inverted peak can be observed at a potential close to +0.2V (vs Ag/AgCl at pH 2) and separated 0.4 and 0.8 V from the two other oxidation peaks obtained during the anodic scan and in such conditions that the surface is particularly activated to favour this electrochemical process. The response obtained in the electronic current for the different peaks when GHB concentration and scan rate were changed allows inferring that these are the result of a potential dependent mechanism. Keywords: GHB, electrochemical oxidation, platinum electrode, Forensic Science.