NOVELTY - The process for activating a diamond-based electrode in a framework using an assembly equipped with a reference electrode, a work electrode & a counter electrode to restore an electrochemical reactivity of the electrode, comprises subjecting the electrode in the presence of a deaerated aqueous solution containing a non-electroactive ionic electrolyte to an equilibrium potential alternately of cathodic and anodic polarization and of increasing amplitude until an anodic and cathodic current density of 10 mu A/cm2 to 1 mA/cm2 is obtained.    USE - The process is useful for activating a diamond-based electrode in a framework using an assembly equipped with a reference electrode, a work electrode and a counter electrode to restore an electrochemical reactivity of the electrode, where the electrode is useful for electrochemical analysis and trace element detection in biotechnology and grafting applications and for effluent pollution control in chemical, metallurgical, agroalimentary and urban water industries (all claimed).    ADVANTAGE - The process is capable of quickly and continuously activating the diamond-based electrode thus improving the electrochemical reactivity and stability of the electrode without any damage.    DETAILED DESCRIPTION - The process for activating a diamond-based electrode in a framework using an assembly equipped with a reference electrode, a work electrode and a counter electrode to restore an electrochemical reactivity of the electrode, comprises subjecting the electrode in the presence of a deaerated aqueous solution containing a non-electroactive ionic electrolyte to an equilibrium potential alternately of cathodic and anodic polarization and of increasing amplitude until an anodic and cathodic current density of 10 mu A/cm2 to 1 mA/cm2 is obtained. The diamond-based electrode is constituted of mono, macro, micro, nanocrystalline or ultrananocrystalline diamond, and comprises a diamond doped by a doping agent. Alternation between cathodic and anodic polarization for each potential is carried out with a speed of 50-150 mV/s. The work electrode corresponds to the diamond-based electrode. An INDEPENDENT CLAIM is included for an activated diamond-based electrode.    DESCRIPTION OF DRAWING(S) - The diagram shows a determination of a potential window of an electrode.