In this study, gold nanoelectrodes were fabricated via electrical deposition of gold nanoparticles (NPs) onto FTO electrodes using cyclic voltammetry (CV) in 1 M H3PO4 solution at a scan rate of 100 mV.s−1 in the potential range of 0–1.4 V and −0.5–0.6 V. The fabricated FTO/AuNP electrodes were characterised by UV–vis, scanning electron microscope, energy-dispersive X-ray spectroscopy, as well as CV and linear sweep voltammetry; the presence of gold on the electrode surface and its electrochemical properties were confirmed towards hydroquinone. The electrodes with the best electrochemical properties were chosen for arsenic(III) determination. The fabricated FTO/AuNP electrodes in the potential range of 0–1.4 V exhibited the high sensitivity with limit of detection (LOD) of 3.04 ppb and limit of quantitation (LOQ) of 9.23 ppb, whereas the FTO/AuNP electrode fabricated in the potential range of −0.5 V–0.6 V displayed the enhancement sensitivity with LOD = 0.623 ppb and LOQ = 1.89 ppb.