Modeling the chromatographic response of inverse size-exclusion chromatography

The pore-size distribution of a liquid-saturated porous medium can be determined by inverse size-exclusion chromatography under suitable conditions. A pair of coupled partial differential equations describes the mathematical model quantifying the limitations of longitudinal dispersion, intraparticle diffusion and adsorption. A temporal moment solution technique is usually used to obtain the moments of the elution curve with simplifying assumptions on the boundary conditions. The moments are then used to-determine the chromatographic response and the pore-size distribution. A computational procedure based on the finite-difference method has been developed to solve the model. The validity of the moment technique to solve these equations has been investigated by comparing the solution obtained by the numerical method with that obtained by the moment technique. The effect of the simplification of the boundary condition is examined and the elution curves for the cases of linear and non-linear adsorption of the solute are determined. (C) 2001 Elsevier Science Ltd. All rights reserved.