Specific and nonspecific adsorption in affinity chromatography.: Part II.: Kinetic and mass transfer studies

The partition coefficient, adsorption equilibrium inside particles, adsorption kinetics, and mass transfer effects have keen studied for asparaginase on Sepharose 4B activated with cyanogen bromide and with hexamethylenediamine and L-(+)-chlorosuccinamic acid as the spacer arm and ligand, respectively, for temperature and pH ranges of 298-302 K and 7.5-8.6, respectively, and for an ionic strength value of 0.05 M NaCl. A dynamic model has been developed to describe the adsorption. This model allowed us to obtain values of the diffusion coefficients and the forward surface interaction rate constants (D-e approximate to 10(-8) cm(2)/s, k(1) approximate to 10(-4) mL mg(-1) s(-1)). The forward surface interaction rate constant does not vary with the pH; however, an Arrhenius-type variation was observed with temperature. The values obtained for these constants range between 3.78 x 10(-4) and 6.80 x 10(-4) mt mg(-1) s(-1). The diffusion coefficient increases with pH (7.5-8.6). Additionally, within the temperature range studied, this coefficient was seen to follow Arrhenius-type behavior, allowing for a determination of the activation energies of the diffusion process for the different pH values (7.95-16.03 kcal/mol).