Separation of xanthohumol from hop extracts by supercritical fluid chromatography

Supercritical fluid chromatography (SFC) was utilised for separating xanthohumol from hop extract. A mixture of CO2 and a modifier were employed as the mobile phase to increase the solvent strength of CO2. Different columns were utilized as the stationary phase. Pressure range was from 220 bars to 270 bars. Three different temperatures (30 °C; 45 °C; 60 °C), different CO2 mass flow-rates, measured at atmospheric conditions (2.5 g/min; 3.1 g/min; and 3.6 g/min) and a gradient concentration modifier were used for this separation. Pure ethanol, a mixture of ethanol and 0.25% of citric acid, and ethyl acetate were applied as modifiers for the mobile phase. Two different hop extracts, one rich in xanthohumol and another one rich in alpha acids, were mixed and used to perform the experiments. Isolation of xanthohumol from hop extract was achieved by SFC. Optimal parameters for that separation will be shown as well as the effect of those process parameters.