Introduction

A working definition of the field of electrochemistry is the study of charged chemical and biological material. The field of electrochemistry appears to have begun over 200 years ago, with the discovery by Galvani that a frog's limbs responded to the touching of its nerves by a scalpel with a severe twitch when the scalpel was electrically charged by a nearby source (Bockris & Reddy, 1998).

Much of electrochemistry involves the study of the properties of ionic solutions first studied by P. Debye and E. Hückel in the 1920s. The modern field of electrochemistry is separated into two related but distinct aspects: ionic solutions and electrode kinetics. Of course, in the problems of interest in this book, the two are related; however, Bockris and Reddy (1998) point out that the two fields today are significantly different, with the field of what they call “electrodics” branching out to applications in the automobile industry, the study of batteries, and fuel cells.

In this chapter, the essential principles of electrochemistry are presented, enabling a thorough understanding of the chemical principles involved in the study of electrokinetic phenomena to follow. Many biofluids are aqueous mixtures of electrolytes, which are species that are either positively or negatively charged. The mixtures of interest are aqueous and are usually dilute in the electrolyte species. An example of a common electrolyte mixture is phosphate buffered saline (PBS), which contains five different ionic species in an aqueous solution.