Controlled-cycle counter-current chromatography.

The application of the technique of controlled-cycle operation to counter-current chromatography is suggested and evaluated. The operating cycle as applied to a chromatographic column would consist of two individually timed periods: (1) Flow period: a specified volume of mobile phase is fed into one end of the column, conveyed through it, and discharged out of the other end of the column. (2) Delay period: an equilibrium concentration distribution between the phases is allowed to be reached. Mathematical description of controlled-cycle chromatography, using an idealized model, is given and theoretical chromatograms of three-component samples for conventional continuous and controlled-cycle operations are compared. It is shown that for certain conditions the controlled-cycle operation could provide by an order of magnitude greater efficiencies (measured with number of theoretical plates) than conventional operation of a chromatographic column.