DISPLACEMENT EFFECT IN MULTICOMPONENT CHROMATOGRAPHY

The study of interference effects is of fundamental importance in understanding multicomponent chromatography. In this work, a displacement effect is examined and shown to be able to explain the dominating interference effects in three major modes of chromatography—frontal, elution, and displacement—involving competitive isotherms. It is concluded that the concentration profile of a component usually becomes sharper due to the displacement effect from another component, while the concentration front of the displacer is usually diffused. Five factors that escalate the displacement effect in multicomponent elution were investigated. A binary elution with a competing modifier in the mobile phase was also discussed. This study was carried out using computer simulations based on a general nonlinear multicomponent rate equation model that considers axial dispersion, external mass transfer, intraparticle diffusion, and Langmuir isotherms. The use of the general model helps the visualization of the multicomponent interactions in chromatography under mass transfer conditions. Copyright © 1990 American Institute of Chemical Engineers