Study of the mass transfer kinetics of BSA on a TSK-GEL DEAE-5PW anion exchanger in a wide concentration range

The adsorption isotherms of bovine serum albumin (BSA) on TOSOHAAS TSK-GEL DEAE-5PW were determined in a pH = 7.5 buffer for a 1.0 mL/min flow rate and at pH 6.0 for 1.0, 2.0, and 3.0 mL/min flow rates. The isotherm data were derived from the breakthrough curves obtained by step series frontal analysis (FA) method. The sample concentrations ranged from ca. 0.2 to 3 mg/mL. From the Scatchard plots, it was found that the bi-langmuir isotherm model fits the adsorption isotherm data better than the single Langmuir isotherm model at both pH = 7.5 and 6.0, for flow rates up to 2.0 mL/min. The rate of the mass transfer kinetics was determined for each breakthrough curve by using a lumped kinetic model. An average rate coefficient of mass transfer kinetics was derived. This rate coefficient depends linearly on the average sample concentration.