Solvent selection in countercurrent chromatography using small-volume hydrostatic columns
Abstract
The preparative chromatographic technique called countercurrent chromatography (CCC) faces two major problems: first, to find the appropriate biphasic liquid system for the desired purification, and second, to retain enough liquid stationary phase inside the CCC column so that the preparative separation can be achieved. In this study, a small-volume (38 mL) hydrostatic CCC column with rotary seals working at pressures as high as 70 bar and rotor rotation speeds as high as 3000 rpm was used to quickly estimate the separation properties of a given biphasic liquid system. The usefulness of this technique was demonstrated in the direct measurement of octanol-water partition coefficients. This approach can be used to purify milligram quantities of materials, but more importantly, the results obtained (solute partition coefficients) can be directly transposed to methods using larger CCC columns -- both hydrostatic and hydrodynamic -- for larger loads using the same biphasic liquid system.