Rolet-Menet

Analytical Chemistry Laboratory, Unit of Formation and Research (UFR) of Pharmaceutical and Biological Sciences, Paris, France 

Before any use, the column is first filled with stationary phase and then rotated at the desired rotational speed. The mobile phase is then pumped into the cartridge at the desired flow rate and pushes out of the column a certain volume of stationary phase. Hydrostatic equilibrium is reached when the mobile phase is expelled at the column outlet. The retention of stationary phase, Sp, is defined as 5p = vy t, where Vg is the stationary phase volume in the column after equilibrium and V, the total volume of the column. 

The value of Sp depends on several parameters, including the hydrodynamic properties of the channels, the centrifugal force (Sp increases to reach a maximum with the centrifugal force), the Coriolis force defined by the clockwise or counterclockwise column rotation (higher retention of stationary phase is obtained with counterclockwise rotation), the mobile-phase flow rate (Sp decreases linearly with mobile-phase flow-rate), the physical properties of the solvent system (such as viscosity, density, interfacial tension), the sample volume, the sample concentration, the tensioactive properties of the 

Van Buel, Van der Wielen, and Luyben have proposed a model to explain the considerable pressure drop arising in the column during CPC separation. The overall pressure drop is the sum of the hydrostatic pressure drop term and the hydrodynamic pressure drop terms over the individual parts of the system. The hydrostatic contribution is caused by the difference in density between the liquids in the ducts and in the channels (APstat = nlApu/R, where n is the number of channels, I the height of stationary phase in the channel, Ap the density difference between the phases. 

Source From Pressure drop in centrifugal partition chromatography, in Centrifugal Partition Chromatography  

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J.-M. Menet and M. C. Rolet-Menet, Characterization of the solvent systems used in countercurrent chromatography, in Countercurrent Chromatography, (J. M. Menet and D. Thiebaut, eds.), Marcel Dekker, Inc., New York, 1999. 

Menet, J.-M. Rolet, M.-C. Thiebaut, D. Rosset, R. Ito, Y. Fundamental chromatographic parameters in countercurrent chromatography influence of the volume of stationary phase and the flow-rate. J. Liq. Chromatogr. 1992,15, 2883-2908. 

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