ABSTRACT
Previous chapters have examined the use of affinity chromatography in the isolation of substances and in their analysis. However, this method can also be used to study the interactions between two or more chemicals. When employed for this purpose, this approach is often referred to as analytical affinity chromatography, quantitative affinity chromatography, or biochromatography [1-3]. One way this might be performed is by using the format given in Figure 22.1, in which the ligand of interest is immobilized in an affinity column while injections are made of a complementary solute in the mobile phase. By examining the elution time or volume of the solute after it has passed through the column, it is possible to obtain information on the equilibrium constants that describe the analyte’s binding to the affinity ligand. If additional agents are also present in the mobile phase, data can be obtained on how these agents affect the solute-ligand interaction. Furthermore, information on the rates
Figure 22.1 Reaction model for the study of solute-ligand binding by affinity chromatography, where A is the injected or applied analyte, I is a competing agent added in a known concentration to the mobile phase, and L is the immobilized ligand. The terms KA and KI are the association equilibrium constants for the binding of A and I to L, respectively. (Reproduced with permission from Hage, D.S., J. Chromatogr. B, 768, 3-20, 2002.)
of these binding processes can be acquired by examining the shape of the solute’s elution profile. As will be seen later, all of these approaches have been used in the study of biological interactions.
