Chapter 13
Dynamic Electrochemistry Transduction Methods
13.1 Introduction
Electrochemical reactions can be monitored under either equilibrium or non-equilibrium conditions. Equilibrium conditions are characteristic of potentiometric sensors in which the response is represented by the electromotive force of the cell. The overall reaction rate under equilibrium conditions is zero.
Under non-equilibrium conditions, the electrochemical reaction proceeds in a definite direction as either oxidation or reduction. Consequently, reactants are consumed and products form by electron transfer reactions that give rise to an electrical current flowing through the cell. In many electrochemical methods, the current measured at a given electrode potential represents the analytical response as the current is dependent on the reactant concentration. These methods are known as amperometric methods. In certain methods the potential is varied over a particular region in order to record a current-potential curve on which the current is measured at a particular potential so as to obtain good sensitivity and minimal interference. A method in which the current-potential curve is recorded for analytical purposes is termed a voltammetric method.
A series of dynamic electrochemistry methods require rigorous control of the electrode potential, which function as the independent variable (the excitation signal) whilst the current is the dependent variable. That is the reason why such methods are classified ...
