MODELING OF LIQUID-CHROMATOGRAPHY EQUILIBRIA

Liquid chromatography models based on continuity equations are very powerful in describing the phenomena encountered in the separation process of biomolecules, especially in mass overload conditions, since these models are able to handle non-linear adsorption problems. Nevertheless, they remain useless unless they are fed with the appropriate equations, i.e. the adsorption isotherms, describing the basic thermodynamical equilibria between the biomolecules in the flowing mobile phase and the stationary phase. Modelling of liquid chromatography equilibria is therefore of major importance. This review presents the different ways to express adsorption isotherms, competitive or not, in reversed phase chromatography. The modelling of protein isotherms on ionic surfaces is also considered since ion exchange chromatography is being nowadays increasingly used for biopolymer separations.