ABSTRACT
From a thermodynamic point of view, electrochemical oxidation is predicted to be a universal method for the detection of biochemical compounds; however, in practice, only a small fraction of these species are oxidized directly at conventional electrodes in the potential range of common electrolytes. Unfavorable electron-transfer kinetics in combination with passivation of electrode surfaces by either the test compounds or their oxidation products (and intermediates) places this limitation on the use of electrochemical oxidation in analytical biochemistry. An obvious strategy is to employ a catalyst to accelerate the electron-transfer kinetics. One objective of this chapter is to demonstrate that some surface-modified and composite electrodes not only lower the potential of oxidation of various classes of biochemical compounds into a range accessible in aqueous solution but also are sufficiently stable for practical analytical methodology.
