APPLICATION OF THE SHOCK LAYER THEORY TO THE DETERMINATION OF THE MASS-TRANSFER RATE COEFFICIENT AND ITS CONCENTRATION-DEPENDENCE FOR PROTEINS ON ANION-EXCHANGE COLUMNS

The extension of the shock layer theory to systems having a slow mass transfer kinetics and a concentration-dependent rate coefficient is di scussed. Experiments were carried out with bovine serum albumin on two anion exchangers, TSK-GEL-DEAE-5PW and Resource-Q. The adsorption iso therm data, determined by single-step frontal analysis, could be fitte d to simplified bi-langmuir equations with very small residuals. A lum ped kinetic model (solid film linear driving force model, with rate co efficient k(f)) was used to account for the mass transfer kinetics. Th e profile of each breakthrough curve (BC) was fitted to the curve calc ulated with this transport model and the rate coefficient k(f) obtaine d by identification. A linear dependence of k(f) on the average: conce ntration of the step of the BC was found. The shock layer thicknesses (SLT) calculated for different relative concentrations agreed very wel l with the experimental results. This justifies the use of the SLT for : the direct determination of rate coefficients.