Graphite nanopowder chemically modified electrode for hydrogen peroxide sensing

Environmental and Analytical Chemistry Division, School of Advanced Sciences, Vellore Institute of Technology University, Vellore-632 014, Tamilnadu, India E-mail : askumarchem@yahoo.com Chemically modified electrodes (CMEs) are the recent impeccable achievements of electrochemists. The point lies in making simpler CMEs without any complicated methods of preparations. Here in, we present a graphite nanopowder (GNP) coated glassy carbon electrode (GCE), designated as GCE/GNP, for simple electrochemical sensing of H2O2 in pH 7 phosphate buffer solution. Note that H2O2 is extensively used in cosmetics and food products (as preservative in milk) and if the usable concentration exceeds certain limit then it may lead to severe health hazards. Thus, simple and low cost detection methodologies are most needed for the real sample analysis. Meanwhile, carbon nanomaterial have attracted great interest among researchers due to their unique structures, good electrical, mechanical, and chemical properties. GNP is one of such carbon nanomaterial which is very cheap and easy available in market. Here in we report a GCE/GNP modified electrode, without any enzyme and addition redox mediator, as a sensor for H2O2 . CV of the GCE/GNP showed a H2O2 -reduction peak at –0.5 V vs Ag/AgCl in pH 7 phosphate buffer solution. Control experiments with activated charcoal modified and unmodified glassy carbon electrodes failed to show any such marked H2O2 reduction signal. Furthermore, GCE/GNP was subjected to amperometric i–t curve technique which gave significant response to H2O2 -sensing. Biochemicals like cysteine, ascorbic acid, uric acid, dopamine and nitrate were also tested for interference