INTRAPARTICLE PROTEIN DIFFUSION EFFECT ON GRADIENT ELUTION CHROMATOGRAPHY

The diffusion of proteins in adsorbent particles is an important step in gradient elution processes used for protein purification. A mathema tical model, which takes into account the combined effects of axial di spersion, film mass-transfer resistance, intraparticle diffusion and a dsorption equilibrium, was used to simulate the gradient elution proce ss in a diethylaminoethyl ion-exchange chromatography. The effects of three important factors: intraparticle diffusivity, adsorbent particle diameter, and linear gradient slope on the separation of beta-lactogl obulin A and beta-lactoglobulin B were investigated individually. The restricted diffusion correlation was used to estimate protein intrapar ticle diffusivities in polymer matrices using the molecular weight of the protein and the polymer concentration (Boyer, P. M. and Hsu, J. T. AIChE J. 1992, 38, 259). The combined effects of these three factors on the resolution of beta-lactoglobulin A and beta-lactoglobulin B sep aration were also studied. A general strategy for design and optimizat ion of gradient elution process for biochemical separations was sugges ted based on our investigation.