Application of Supercritical Fluid Extraction and Chromatography to Assay Fat-Soluble Vitamins in Hydrophobic Ointment

The determination of retinol palmitate and tocopherol acetate in a hydrophobic ointment by a coupled supercritical fluid extraction (SFE) and supercritical fluid chromatography (SFC) system is described. The ointment, triturated with diatomaceous earth powder, was subjected to SFE with carbon dioxide, and the extract containing fat-soluble vitamins was trapped on a trimethylsilyl silica-gel column by reducing the fluid pressure. The trapped components were analyzed on an octadecylsilyl silica-gel column by SFC using carbon dioxide containing ethanol as a mobile phase and UV absorption monitoring at 284nm. In this method, retinol palmitate and tocopherol acetate in preparations could be determined within ten minutes without any manual products after placing the sample into the system.