Deep eutectic solvents in countercurrent and centrifugal partition chromatography

• Application of deep eutectic solvents (DES) in liquid-liquid chromatography.
• DES-based solvent systems as promising water-free biphasic solvent systems.
• Separation of hydrophobic substances by a centrifugal partition extractor (CPE).
• CPE column suitable for separations using DES-based biphasic solvent systems.

Deep eutectic solvents (DESs) were evaluated as solvents in centrifugal partition chromatography, a liquid-liquid chromatography separation technology. To this end, the partition coefficients of ten natural compounds of different hydrophobicity were determined in non-aqueous biphasic systems containing DES. The influence of the composition of DESs and the presence of water in the biphasic system on the partition coefficient were also examined. In addition, several process relevant physical properties of the biphasic system, such as the density and viscosity of the phases, were measured. A mixture of three to four hydrophobic compounds was successfully separated in a centrifugal partition extractor using a heptane/ethanol/DES biphasic system.