Intraparticle protein diffusion effect on gradient elution chromatography

Abstract

The diffusion of proteins in adsorbent particles is an important step in gradient elution processes used for protein purification. A mathematical model, which takes into account the combined effects of axial dispersion, film mass-transfer resistance, intraparticle diffusion and adsorption equilibrium, was used to simulate the gradient elution process 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 β-lactoglobulin A and β-lactoglobulin B were investigated individually. The restricted diffusion correlation was used to estimate protein intraparticle 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 β-lactoglobulin A and β-lactoglobulin B separation were also studied. A general strategy for design and optimization of gradient elution process for biochemical separations was suggested based on our investigation.