The present disclosure relates to a sensor for detecting hydrogen ions in an aqueous solution comprising a support, a reference electrode, a working electrode and a counter electrode supported by said support, the reference electrode being made of a material comprising silver and silver chloride, the counter electrode being made of a conductive material. The working electrode comprises a substrate and a layer made of an inherently electrically conductive polymer of the polythiophene or polyaniline (PANI) or polypyrrole class.