We report for the first time a novel electrochemical treatment applied to a glassy carbon electrode (GCE) during p‐nitrophenol (PNP) oxidation and dedicated to the limitation of electrode passivation by nitrophenol compounds oxidation. We propose an electrochemical process of direct phenol oxidation by starting the electrolysis at a very low potential,− 1.2 V/SCE, in order to generate a soluble monomer, p‐aminophenol, on the electrode surface. Then, p‐aminophenol elaborated on the electrode surface in the place of oligomers, gives benzoquinone as a by‐product and no film formation was observed. Furthermore, the presence of ap‐NiTSPc (film of nickel tetrasulfonated phtalocyanine) coating permitted to increase two times the electrode sensitivity without passivation, too.