Electroanalysis with Carbon Film-based Electrodes

As electrode materials for analytical applications, carbon-based electrodes have been widely employed as detectors for high performance liquid chromatography (HPLC), capillary electrophoresis (CE) and various biosensors. Carbon materials usually shows wider potential window compared with those of novel metals such as platinum and gold electrode. These electrodes are chemically stable, highly conductive and low cost. A recent review article has well described the electrochemistry of certain carbon-based electrodes [1]. Glassy carbon (GC) and highly oriented pyrolytic graphite (HOPG) have been traditionally utilized for various electroanalytical methods. Later, carbon paste electrodes have been used mainly to develop enzymatic biosensors because carbon paste is low cost and the electrode can be fabricated only by printing and various biomolecules can be modified only by mixing with carbon ink. In the last 20 years, electrochemical measurements using boron-doped diamond (BDD) electrodes have become more intensively studied by many groups [2–4]. A BDD electrode shows extremely wider potential window due to its chemical stability and lower background noise level than other electrode materials. Due to such unique performances, BDD electrodes are advantageous in terms of detecting various species including heavy metal ions (Pb2+, Cd2+) [5], chlorinated phenols [6], histamine and serotonin [7, 8], and even nonmetal proteins [9]. The BDD electrodes have also been employed to fabricate modified electrodes including As3+ detection with iridiumimplanted BDD [10], DNA modified BDD [11] and cytochrome c modified BDD [12]. In spite of excellent performance of BDD electrodes, high temperature between 400–700° C is needed for BDD fabrication, which limits the substrates only to inorganic materials such as silicon wafer, metals and glass plate. More recently, nanocarbon materials including carbon nanotubes (CNTs), carbon nanofibers (CNFs) and graphene nanosheet have been more intensively studied with a view to using them as electrode materials for fuel and biofuel cells [13–15]. For electroanalytical application CNT and graphene have been employed to fabricate various Electroanalysis with Carbon Film-based Electrodes Shunsuke Shiba, Tomoyuki Kamata, Dai Kato and Osamu Niwa