Theoretical analysis of the behavior of an heterogeneously packed chromatographic column

The properties of a chromatographic column packed with a nonhomogeneous mix ture of two slightly different packing materials are studied by calculating the migration, the broadening, and the shape alteration of a rectangular b and moving under nonlinear conditions along such a column. For the sake of simplicity, the column bed is assumed to be an alternate set of coaxial ann ular columns of the two materials. A two-dimensional implementation of the equilibrium-dispersive model permits the study of problems of this type, re quiring two space dimensions for their modeling, such as this nonhomogeneou s column with cylindrical symmetry, a nonplanar injection with a cylindrica l symmetry, or a cylindrical central injection. The axial and radial profil es of the band inside the column and its elution profiles are calculated. T hese profiles depend on both the radial and the axial dispersion coefficien ts and on the relative difference between the separation factor of the two materials. (C) 1998 Elsevier Science B.V. All rights reserved.