Abstract: Para aminobenzene sulfonic acid(p-ABSA) was deposited onto the surface of a glass carbon electrode(GCE) through the electrochemical deposition. Cation-exchange properties of the deposited p-ABSA were then employed to confine ferric ion(Fe3+) within the polymeric layer. Ferrocyanide ions([Fe(CN)6]4-) can react with the adsorbed Fe3+ forming Prussian blue(PB). PB crystals were formed by alternative adsorption of Fe3+ and reaction with [Fe(CN)6]4-. The crystal shows high catalytic activity toward the electrochemical reduction of hydrogen peroxide. Cyclic voltammetry, electrochemical impedance spectroscopy and typical amperometric response method were employed to characterize the electrochemical properties of the PB modified electrode. The experimental parameters(applied potential, pH, and interfering substances) influencing the performance of the PB modified electrode were investigated in details. Under optimal conditions, the PB modified electrode exhibits a wider linear range of 0.97~32.33 mmol/L with the fast response less than 5 s and a low detection limit of 0.48 mmol/L(S/N=3).

Key words: Prussian blue, p-aminobenzene sulfonic acid, ferric ion, ferrocyanide, hydrogen peroxide