INVESTIGATION OF DISPLACER EQUILIBRIUM PROPERTIES AND MOBILE-PHASE OPERATING-CONDITIONS IN ION-EXCHANGE DISPLACEMENT CHROMATOGRAPHY

One of the major advantages of displacement chromatography is the simu ltaneous concentration and purification that can be effected during th e process. The steric mass-action model of non-linear ion-exchange chr omatography is employed to investigate the affects of mobile phase sal t concentration and displacer equilibrium properties on the concentrat ion of proteins in isotachic displacement zones. The results indicate that the salt microenvironment in displacement zones plays a major rol e in determining the concentration of the displaced proteins. The para meters which affect the salt microenvironment are both the initial sal t concentration in the carrier as well as the induced gradient produce d during the displacement process. For a given breakthrough volume, th e induced gradient is determined by the ratio of the steric factor to the characteristic charge of the displacer. These results indicate tha t the use of relatively low salt concentrations in the carrier along w ith displacers with relatively high steric factor to characteristic ch arge ratios will produce significant concentration of the proteins dur ing the purification process.