Modeling of equilibrium and kinetics of human polyclonal immunoglobulin G adsorption on a tentacle cation exchanger

Adsorption of human immunoglobulin G (IgG) on a commercial cation exchanger with a grafted polymer layer was investigated at pH 4.5 and in the NaCl concentration range of 0-150 mM. Adsorption equilibrium was determined in static batch experiments and verified in batch uptake experiments. Parameters of the Langmuir isotherm were estimated for each salt concentration separately. The batch uptake experiments provided also the estimates of effective pore diffusion coefficients of IgG for individual protein and salt concentrations. The values of the effective pore diffusion coefficient depended strongly on both factors. They increased by about 5-15 times with the NaCl concentration and decreased about three times with the protein concentration. The quality of the estimated parameters was confirmed by frontal experiments described by the general rate model of chromatography.