Effects of adsorption kinetics and surface heterogeneity on band spreading in perfusion chromatography—a network model analysis

A network model was used to simulate the band-spreading of an eluting solute from a perfusive column under retained conditions. The computer experiments were carried out over a wide range of Peclet numbers. The effects of pore size distribution (PSD), pore inter-connectivity and linear adsorption/desorption kinetics were taken into account in the simulations. Surface heterogeneity effects were also discussed. Among these parameters investigated, adsorption/desorption kinetics was the most important parameter, which influenced the transit-time moments and, in turn, the band-spreading as well as band-tailing results significantly over the whole range of Peclet numbers investigated. In addition, pore inter-connectivity and PSD also play an important role in determining the band-spreading results. However, their effects are only important in the molecular diffusion- and convection-controlled regimes. Under strongly retained conditions, contribution of hydrodynamics can be neglected. Furthermore, surface energetic heterogeneity resulting from the wide pore size distributions could exacerbate both band spreading and band tailing; the effects on band tailing being more significant than those on band spreading.