Correlating physical properties of aqueous-organic solvent systems and stationary phase retention in a centrifugal partition chromatograph in descending mode.

Abstract

The performance of the Centrifugal Partition Chromatography (CPC) as a liquid-liquid chromatographic technique depends strongly on the two-phase solvent system used. Thereby the individual influence of the retention of the stationary phase, the coalescence, and the dispersion of the mobile phase in the chambers must be understood to select appropriate solvent systems and reach high separation efficiencies. In this study, an optical measurement system was used to investigate the influence of the physical properties of the Arizona solvent systems on the stationary phase retention in descending mode. Therefore, physical properties like density, viscosity, and interfacial tension were measured as well as the stationary phase retention. Using dimensionless numbers, a correlation between the stationary phase retention and the influencing parameters could be determined. The correlation was validated using data from the literature. Additionally, the solvent systems were modified by additives to identify the validity of the correlation. It was proven that the dimensionless numbers Capillary number (Ca) and Morton number (Mo) can be used to predict the stationary phase retention of other liquid-liquid solvent systems as well as for different operating conditions.