Arylated gold NPs were coated on the surface of a glassy carbon electrode (GCE, 0.07cm 2 ) using 2 drops of 0.5 µL (1 µL) of the suspension of gold NPs which was previously well homogenized and sonicated. The nanoparticle-coated GCE was dried at 35 ͦ C. The behavior of the modified electrode thus obtained was measured cyclic voltammetry (CV) in a 0.1 M NaOH basic medium in a potential range between -0.1 and 1.5 V vs ECS. We investigated the catalytic properties of modified nanoparticles for the oxidation of ethanol at different concentrations of 0, 0.5, 1, 1.5, 2 and 2.5 M ethanol. A three-electrode electrochemical cell with a volume of 20 mL electrolyte containing the 0.1M NaOH solution was used. The reference, the counter and the working electrodes were saturated calomel, stainless steel grid and the coated GCE 3 mm diameter. GCE was polished, washed with ethanol and dried with compressed air prior to each use.