ABSTRACT
Both natural and synthesized amino acids are complex mixtures of substances that resemble each other closely. Their initial solutions may contain tens, hundreds, or even thousands of components, many of which are closely related to the desired product in terms of their physical-chemical properties. Ion-exchange chromatography continues to be a popular method for the preparation and analysis of amino acids. For four decades, ion-exchange equilibria of amino acids have been the subject of numerous experimental and theoretical investigations. Amino acids constitute a particularly important class of bifunctional compounds; the two functional groups in an amino acid are, respectively, basic and acidic, the compounds are amphoteric, and in fact exist as zwitterions or inner salts.
