Dopamine adsorption and electrochemistry on carbon electrodes

Scanning Electrochemical Cell Microscopy (SECCM) has been used to gain knowledge of dopamine (DA) electrochemistry on carbon surfaces. This work expands the scope of application of SECCM to study functionalised carbon surfaces, such as glassy carbon (GC), and study microscopically complex structured surfaces such as the wall of a carbon fibre. In this work, SECCM is used in amperometric static mode to functionalize GC with two different electrolyte media: acidic and basic. Using voltammetric hopping mode to both anodised and pristine surface regions of GC during the same SECCM experiment, DA adsorption and electrochemical behaviour was evaluated with the aid of Fast Scan Cyclic Voltammetry (FSCV). The electrochemical behaviour of DA was then correlated to the results of a range of characterisation techniques to determine the effect of surface properties after anodisation on DA adsorption and electron transfer kinetics. The later part of the thesis demonstrates SECCM hopping mode voltammetric analysis of a complex and rough surface such as a carbon fibre wall. Carbon fibre electrodes are widely used for in vivo analysis but understanding of the electrochemical heterogeneity of the carbon fibre wall is lacking. Finally, the thesis demonstrates a novel SECCM cleaning protocol to prevent the accumulation of DA oxidation products in the SECCM meniscus together with a particular approach for studies of DA adsorption kinetics. Overall, this work opens up a wide range of different possibilities for SECCM to study not only complex electrode surfaces but also complex electrochemical systems such as DA adsorption and electro- oxidation