The Influence of Temperature on Stationary Phase Retention in Countercurrent Chromatography: Integrating Experiment...

The selection of a biphasic solvent system is the first and most important step for a successful countercurrent chromatography (CCC) separation. The partitioning coefficient of targets and their related impurities on one side, and the stationary phase retention on the other, are among the parameters used for solvent system selection. At constant temperature, the stationary phase retention of a selected solvent system in any CCC instrument is dominated by the rule of Du's plot, which describes the correlation between stationary phase retention and flow rate. In a biphasic liquid system, physico-chemical properties such as density, viscosity, and interfacial tension between two phases are temperature dependent. In this article, the effect of temperature on the retention of several typical solvent systems was investigated using a high-speed CCC (HSCCC) instrument. The results showed that temperature changes could induce density, viscosity, and interfacial tension variation of the biphasic system with consequent changes in the system's hydrodynamic behavior. As the temperature increased, the density and viscosity of the selected solvent system decreased. This led to a variation in the interfacial tension between two phases depending on the solvent system composition. The stationary phase retention increased when the temperature increased for the tested solvent systems. Based on the obtained results, an improved Du's plot was suggested, accounting for the contribution of operating temperature. The prospect of this article provides hands-on strategies for the development of high-performance separation method for HSCCC.