Determination of Antioxidants in Human Skin by Capillary Zone Electrophoresis and Potentiometry

This study reports on the determination of water-soluble antioxidants from human skin by potentiometry and capillary zone electrophoresis. A rapid and simple capillary electrophoretic method was developed for the determination of ascorbic acid, uric acid, and glutathione. The limits of detection were 1.5 µ mol L−1 for uric acid, 4.5 µ mol L−1 for glutathione, and 9 µ mol L−1 for ascorbic acid with spectrophotometric detection at 190 nm. The procedure was used to analyze aqueous extracts from human skin. The results by both methods were in good agreement. Uric acid was shown to be a major component in the extract by capillary zone electrophoresis. The uric acid might also be primarily responsible for the potentiometric signal.