Determination of sunscreen agents in cosmetic products by supercritical fluid extraction and high-performance liquid chromatography

A rapid supercritical fluid extraction (SFE) procedure for the isolation of five of the most common sunscreen agents (2-ethylhexyl-p-dimethylaminobenz oate, 2-hydroxy-4-methoxybenzophenone, 2-ethylhexyl-p-methoxycinnamate, 4-m ethylbenzylidene camphor and 4-tert.-butyl-4'-methoxydibenzoylmethane) from cosmetic products is described. Investigation of the factors affecting the extraction efficiency in SFE indicated that sunscreen recoveries were affe cted mainly by the supercritical CO2 pressure and by the trapping method. T he sunscreens were analyzed by reversed-phase high-performance liquid chrom atography after a 10-min extraction of the cosmetic product with CO2 at 250 bar and 40 degrees C, using sequential glass surface and C-18 sorbent as c ollection system. A quantitative comparison of SFE with a liquid extraction procedure was performed on commercial cosmetics. The SFE method yielded re coveries higher than 94.8% compared with conventional liquid extraction and exhibited a precision better than 5.3% relative standard deviation. Moreov er, SFE minimized sample handling, reduced the consumption of harmful solve nts and afforded a more effective purification of the cosmetic matrices. (C ) 2000 Elsevier Science B.V. All rights reserved.