3] Ion-exchange chromatography

Abstract

Over the years, electrophoretic techniques were the leading bioanalytical tools for biopolymers. Slab gel electrophoresis has yielded spectacular results, in resolving closely related nucleic acids of high molecular mass. Isoelectric focusing and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) have served well the analytical needs of life scientists and biotechnologists in protein analysis. Electrophoresis has undergone the same metamorphosis as did liquid chromatography at the advent of high-performance liquid chromatography (HPLC). As a result, capillary zone electrophoresis (CZE) has emerged as an instrumental bioanalytical technique of formidable potential. In future, one may expect growing competition between high-performance ion-exchange chromatography also in the form of capillary electrochromatography and capillary electrophoresis. This chapter discusses the employment of ion-exchange chromatography in the analysis of biological macromolecules. A brief review of the fundamentals is followed by a discussion of the various modes of ion-exchange chromatography. Then the stationary phases employed in the ion-exchange columns, which is the heart of the chromatographic system, are described with particular attention given to the novel ion exchangers introduced for high-speed protein separations. Details regarding the methodology and method development are interspersed throughout the text.