Frontal Chromatography for Nonassociable and Micellar Systems

The continuous flow model of chromatography for computer simulations is developed and applied for nonassociable, dimerizing, and micellar systems. This model is more realistic than the discontinuous flow model, since the former takes into account the infinitesimal flow of the mobile phase. The frontal and zonal chromatograms of sucrose, a nonassociable solute, are determined on a Sephadex G-10 column as a function of the total sucrose concentration. The derivative of the frontal chromatogram at the leading boundary completely overlaps with that at the trailing boundary and has the same shape with the zonal chromatogram. Therefore the number of plate can be calculated from the observed derivative chromatogram. For some dimerizing systems the dimerization constant can be estimated from the concentration dependence of the derivative at the trailing boundary, if an appropriate correction is applied. Some characteristic parameters obtained from the derivative chromatogram of the micellar system provide information on the aggregation pattern. The observed results outlined above can be semiquantitatively predicted by the continuous flow model and by the discontinuous flow model, if the void volume and the number of plate are regarded as adjustable parameters in the latter model.