Stochastic simulation of the partition mechanism with a heterogeneous surface phase

A three-dimensional stochastic model of chromatography has been used to determine the effect of multiple sites on the partition mechanism. The effect of additional sites on mass transfer rates, zone profiles, and their statistical moments are investigated as a function of the partition coefficient, diffusion coefficient, and interfacial barrier to mass transfer. These studies have demonstrated that changes in the partition coefficient alone are not sufficient to alter the system response from that of a single site. Changes in the diffusion coefficient and the barrier to mass transfer do cause changes in the response compared to that of a single site. The zone profiles produced by the systems become more asymmetric as the difference between the diffusion coefficients or the barriers to mass transfer increases. The site with the slower mass transfer rate plays the dominant role in the total system response.