Noninvasive Determination of Ligand Concentration of Chromatography Columns for Protein Separations

Abstract

A simple, nondestructive method for characterizing ionizable groups on a polymer matrix is presented. It is based on the pH transition formed by a step change in the ionic strength of buffer solutions. Either height or duration of the pH transition excursion was shown to be linearly proportional to the amount of groups determined by elemental analysis. The method can be applied to ion-exchange groups, but also to any other group of ionizable character, such as chelating groups. Recently, it was shown that the method can be extended to estimate the amount of immobilized protein.