Separation Science and Technology, Vol.35, No.11, 1719-1742, 2000
A methodology for the characterization of ion-exchange resins
Tremendous strides have been made in the field of stationary phase synthesis over the course of the last decade. Although important research has been carried out to elucidate the characteristics of various resins, there is currently a lack of understanding regarding the effect of the various resin materials on preparative modes of chromatography. To describe preparative chromatography, one needs to have appropriate isotherm and transport models. In this article a methodology is presented to enable the identification of appropriate transport models to describe the chromatographic behavior of solutes in preparative ion-exchange systems. The methodology involves simple pulse experiments to estimate the various transport parameters followed by the construction and analysis of various dimensionless groups to identify the dominant transport mechanisms in a given resin. Following this, one can identify an appropriate transport model to describe the chromatographic behavior of solutes on the resin material. This model is then employed in concert with the steric mass action (SMA) isotherm and is validated using experimental data. The results presented provide significant insight into the identification of dominant transport mechanisms on various ion-exchange resin systems.