| 초록 |
A packed-bed chromatographic model developed in this study includes adsorption isotherms considering steric mass action as well as non-linearity in liquid/solid phases, adsorption kinetics and mass transport. Sensitivity and elasticity of model parameters (e.g., steric/shape factors, adsorption heat coefficient, effective protein charge, equilibrium constant, mass transfer coefficient, axial dispersion coefficient and bed voidage) are analyzed for a BSA(bovine serum albumin)-salt system in a low protein concentration range where linear adsorption isotherms are shown. The adsorption heat coefficient, the shape and steric factors have little effect on adsorption isotherms and the retention time. However, the effective protein charge which is related to pH and ionic strength affects the retention time significantly even for a slight change. Due to a steric hindrance of protein binding sites and a salt shielding effect neutralizing the surface charges on the protein, the effective protein charge could depend upon the salt concentration (or ionic strength). |
