ORIGINAL PAPER Microwave-assisted functionalization of glassy carbon spheres: electrochemical and mechanistic studies Malingappa Pandurangappa & Thippeswamy Ramakrishnappa Received: 21 January 2009 / Revised: 18 March 2009 / Accepted: 18 March 2009 / Published online: 25 April 2009 # Springer-Verlag 2009 Abstract Functionalization of glassy carbon spheres have been carried out by microwave irradiation in the presence of modifier molecules through oxidation followed by amidation reaction. The glassy carbon spheres were initially catalyzed by treating with concentrated nitric acid to introduce surface-bound carboxylic groups, and its subse- quent amidation reaction in the presence of p-nitroaniline yields p-nitroanilide-functionalized substrate materials. These derivatized glassy carbon spheres have been electro- chemically characterized by immobilizing them on bppg electrode and studying its voltammetric behavior. X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy studies have revealed that the modifying molecules are surface bound and covalently attached on the carbon substrate. Keywords Microwave irradiation . Functionalization . Glassy carbon spheres . Voltammetry . X-ray photoelectron spectroscopy . p-Nitroaniline Introduction The surface chemistry of graphite and related conducting forms of carbon is of much interest to electrochemists, surface scientists, synthetic chemists, and material scientists in recent years due to its unique properties like chemical inertness, high mechanical strength, good electrical con- ductivity, high surface activity, and wide potential window [1]. In recent years, a lot of emphasis has been laid toward the functionalization of carbon substrate materials, primar- ily due to their potential applications in separation science, adsorption studies, enhancing catalysis, trace metal ion analysis, electroanalysis, chemical sensors, and other electronic components [2, 3]. A few methods such as electrochemical reduction, thermolysis, photolysis, and chemical reduction of diazonium salts have been developed and used for the surface functionalization of different forms of carbon substrates through the reactive intermediates of aryldiazonium salts [4–8]. The resulting reactive species formed such as aryl radical or cationic species can react with the carbon surface, resulting in covalently bonded species [9]. Most of these reactions are based on the use of conventional chemical techniques like refluxing and/or sonication in organic solvents or mineral acids or reducing agents, often making use of high temperatures/pressures, long reaction times, and highly reactive species [10–12]. Consequently, alternative functionalization approaches are highly desirable to enable new protocols easy to execute and scale up. Microwave-assisted organic synthesis enhan- ces the rate of reactions, improves product yield, has low reaction times, as well as shows energy efficiency [13]. A novel fabrication method for the patterned carbon nano- tubes (CNTs) conducting arrays by consecutive condensa- tion reaction and their photolithographic application has been reported [14]. The oxidized nanotubes were treated with long-chain alkylamines via acylation, and the resulting functionalized material is soluble in organic solvents [15]. The lipophilic and hydrophilic dendrimers were covalently attached on oxidized CNT via amidation or esterification reactions [16]. The multiple rapid functionalization of CNTs through 1,3-dipolar cycloaddition of aziridines using microwave energy was reported by Brunetti and coworkers [17]. J Solid State Electrochem (2010) 14:687–695 DOI 10.1007/s10008-009-0834-1 M. Pandurangappa (*) : T. Ramakrishnappa Department of Studies in Chemistry, Bangalore University, Central College Campus, Dr. Ambedkar Veedhi, Bangalore 560 001, India e-mail: mprangachem@gmail.com