Experimental Study On The Purification Of Solanesol By Supercritical Fluid Chromatography

Supercritical fluids are often used as the mobile phase in supercritical fluid chromatography due to their gas-like mass transfer and liquid-like solvating properties. Supercritical fluid chromatography(SFC)is a kind of new technique widely used in the separation field with high efficiency and little environmental hazard, such as the separation of natural products or herbal drugs, and the removal of the impurities.Solanesol is a valuable product with remarkable medical effects such as diminishing inflammation, hemostaria and antibacterial. It is also an important medicine monomer or intermediate for the synthesis of vitamin K₂ and coenzyme Q₁₀. The further application of traditional separation technology of solanesol is limited by complicated operating steps, large discharge capacity and unavoidable solvent residue. In this paper, solanesol in the tobacco extract was purified by SFC.Firstly, the tobacco was extracted by SC-CO₂/ethanol to obtain the extract. Then, the extract was saponified and dewaxed in sequence to remove some impurities in the mixture. Experimental results show that the pretreatments play great roles in the following steps of further purification.After that, the purification of solanesol from the mixture was conducted with the use of the SFC. ZORBAX SB-C18(250mm×9.4mm I.D., 5μm)was chosen as the stationary phase, and the SC-CO₂/methanol as the mobile phase. The influences of the flowrate of the mobile phase and the content of modifier in the mobile phase on the purification process, and the effects of the pressure and temperature on the selectivity and resolution of the solanesol and the impurities were experimentally investigated. Experimental results obtained in this condition indicated that the content of solanesol increased from 7.93% up to 47.98%.At last, the five-parameter mean-field lattice model was used to describe the relations of the capacity factor with the density and temperature of the mobile phase. The parameters were estimated by fitting the experimental data into the model. The comparison indicates that the capacity factor predicted by the model are in good agreement with the experimental data, with a AARD% of 4.87%.