Supercritical fluid extraction and supercritical fluid chromatography of vitamin E in pharmaceutical prepartions

Abstract

Vitamin E contained in solid pharmaceutical and dietetic products was extracted from samples by supercritical fluid extraction and determined by supercritical fluid chromatography. Experimental studies on factors affecting extraction quantitatively were conducted in order to select the most appropriate conditions. Samples were weighed (0.5–1 g) in polymer cartridges and were extracted by CO₂ using a constant flow (2 ml min^–1) during 10–30 min at 400 atm and 60 °C. The extracts were collected into glass vials containing dichloromethane and subsequently transferred to calibrated flasks where they were diluted with 10 ml of dichloromethane . One microlitre of standard and sample solutions was injected, and the chromatography was carried out at 60 °C and with pressure-programming from 100–450 atm. A flame ionization detector was used in the determination. The proposed method is rapid and there is no interference from other constituents of the samples, providing analytical recoveries of 94–102%. Use of CO₂ as both extractant and mobile phase reduces the use of organic solvents to only the small volume necessary to dilute the extracts.