Graphite nanopowder chemically modified electrode for hydrogen peroxide sensing

Abstract

Environmental and Analytical Chemistry Division, School of Advanced Sciences, Vellore Institute of Technology University, Vellore-632 014, Tamilnadu, India E-mail : [email protected] 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.