In order to prepare the modified electrode, the GCE was first polished with 0.3 and 0.05 μm alumina slurry on a polishing cloth. Then, it was thoroughly rinsed with water and sonicated in de-ionized water for 5 min.Finally, it was dried in air for 30 min. The electrodeposition of gold nanoparticles onto GCE surface was performed according to the previously published papers. To this end, GCE first was immersed into a deoxygenated solution of 0.5 M H2SO4 in the presence of 0.1 mM HAuCl4 and 0.1 mM KI for a few seconds.Then, a step potential from 1.1 to 0.0 V was applied to the GC electrode for 45 s in three successive steps(15 + 15 + 15 s). The obtained AuNPs/GCE was thoroughly rinsed with deionized water and placed inside 0.1 M H2SO4 solution. Then, cyclic voltammetry was carried out to clean and activate the surface of modified electrode by scanning the potential between 0–1.6 V for 10 cycles at a scan rate of 0.1 V.S−1.