Development Of Nanoelectrodes For Electrochemical Applications

The demand for direct, selective and rapid determination of chemical and biological analytes has led to a growing interest in electrochemical sensor devices. Particularly the use of nanomaterials and nanoelectrodes has received increased interest due to their enhanced electrochemical properties. In this thesis these enhanced properties are exploited in order to develop multiple sensing applications.Firstly a sensitive microband based sensor is described for the detection of trinitrotoluene and for its discrimination from other nitroaromatic compounds. Square wave voltammetry was used to identify characteristic reduction peaks for these compounds and a calibration plot for the quantification of TNT was also produced.In order for nanowire based sensors to realise their full potential, the contributions of capacitive charging currents must be overcome. A metallic shield layer embedded within the nanowire devices passivation layer is presented as a means of substantially reducing these currents. This is the first instance of a fabrication method such as this being used in this fashion.Finally the thesis describes the development of methods using platinum nanowires for the analysis of hydrogen peroxide as a means of detecting a number of analytes. Mediatorless glucose detection is successfully achieved by entrapping glucose oxidase in an electropolymer at the nanowire surface and then detecting hydrogen peroxide produced as a result of the glucose / glucose oxidase interaction. The development of a method for quantifying hydrogen peroxide in milk for food base applications is also presented. The fabrication of interdigitated array electrodes is also described and these were employed to detect hydrogen peroxide as a product of the oxygen reduction reaction as a method for the reagentless quantification of dissolved oxygen in acidic solutions.