Molecular dynamic theories in chromatography

The molecular dynamic model of chromatography is a microscopic model that consists of two fundamental processes: (i) the random migration of the molecules in the mobile phase, and (ii) the random adsorption-desorption of molecules on the stationary phase. The diffusion and drift of the molecules in the mobile phase is usually described with a simple one-dimensional random walk. The adsorption-desorption process is modeled most of the time by a Poisson process that assumes exponential sojourn times of the molecules in both the mobile and the stationary phases. The molecular dynamic model of chromatography can simply be used to characterize the chromatographic process on heterogeneous stationary phases. It has been applied to reversed phase, chiral, size-exclusion, and ion-exchange separations. (c) 2008 Elsevier B.V. All rights reserved.