The electrochemical detection of H202 was investigated on a cobalt-oxide nanoparticles modified glassy carbon electrode in phosphate buffer solution (pH 7). Cyclic voltammetry at potential range - I I to I I V from CoCI2 natural queous solution produced a well defined cobalt oxide nanopaparticles deposited on the surface of glassy carbon electrode. The surface of resulting electrode was characterized with SEM. The formation of cobalt oxyhydroxide film was investigated by cyclic voltammetry in alkaline and natural aqueous solution. The modified electrode showed well defined and stable redox couples in both alkaline and natural aqueous solution. The modified electrode showed excellent electrocatalytic activity For oxidation of hydrogen peroxide. The response to I12O2 on the modified electrode was examined using cyclic voltammetry and amperometry. The amperometric detection of hydrogen peroxide is carried out at 0 75 V vs Ag/AgCl reference electrode in phosphate butler solution with p1.1 7.4. The detection limit(S/N=3) was 0.4 nM with linearity up to 6 orders of magnitude and sensitivity of 4.86LA/l.IM.cm2. The response time of the electrode to achieve 95% of the steady- state current is < 2 s The immobilization of cobalt oxide nanopanicles on the surface of GC electrode appears to be a highly efficient method for the development of a new class of sensitive, stable and reproducible hydrogen peroxide electrochemical sensor
