On influence of sample loading conditions on peak shape and separation efficiency in preparative isocratic counter-current chromatography

The cell model theory of CCC is extended to develop analytical solutions for various sample loading conditions (non-impulse loading with separate feed stream and with the mobile phase flow, impulse and non-impulse periodic loading). Equations are presented allowing the simulation of the chromatograms for various sample loading conditions. These equations can help to predict the influence of sample loading conditions on the separation of a given feed mixture and select a suitable compromise between the productivity and the resolution in the isocratic preparative and production CCC separations. It is shown that: when the sample loading time is about 2% of the mean residence time, the effect of loading time can be neglected; the loading time about 20% of the mean residence time seems to be quite acceptable; proper selection of the conditions for the sample loading can allow increasing the productivity by an order of magnitude ensuring, a desirable separation.