Electrochemical detection of trace amount of arsenic(III) at glassy carbon electrode modified with cobalt oxide nanoparticles

TLDR: In this paper, a novel cobalt oxide nanoparticles based sensor for the detection of trace amount of As3+ ion in aqueous solution has been developed for detecting arsenic in a glassy carbon electrode.

Abstract: Novel cobalt oxide nanoparticles based sensor for the detection of trace amount of As3+ ion in aqueous solution has been developed. Cyclic voltammetry at potential range −1.1 to 1.1 V from aqueous buffer solution (pH 7) containing CoCl2 produced a well-defined cobalt oxide (CoOx) nanoparticles deposited on the surface of glassy carbon electrode. The resulting electrode surfaces and its morphology were examined with both cyclic voltammetry and scanning electron microscope (SEM) techniques. The modified electrode shows excellent catalytic activity toward arsenic oxidation at wide pH range, 5–11. The response to As3+ on the modified electrode was examined using cyclic voltammetry and hydrodynamic amperometry. The amperometric detection of arsenic is carried out at 0.75 V versus Ag/AgCl reference electrode in phosphate buffer solution with pH 7. The detection limit (S/N = 3) was 11 nM with linearity up to 4 orders of magnitude and sensitivity of 111.3 nA/μM. The response time of the electrode to achieve 95% of the steady-state current is