Simultaneous determination of lycopene and beta-carotene with high-performance liquid chromatography

Lycopene and -carotene, two strong antioxidant carotenoids, enter our bodies mostly through vegetables and fruits. Determination of the serum carotenoid levels may be used both to assess body antioxidant status and to validate vegetable and fruit consumption questionnaires. The aim of this study was to design and setup a rather simple, reliable and less expensive high-performance liquid chromatography (HPLC) -based method for simultaneous determination of serum lycopene and -carotene levels. After examining various chromatographic conditions, the following method was found to be most reliable. َAfter protein precipitation with ethanol, the carotenoids were extracted using n-hexane, which was then evaporated under nitrogen flow at 40°C. The sediment was reconstituted with a mixture of mobile phase (methanol: acetonitrile: tetrahydrofurane, 50:45: 5, v/v/v) and diethyl ether (2:1, v/v), 20µL of which was injected to the column Novopack C18. With a flow rate of 1. 5mL/min at 472nm, retention times of lycopene and -carotene were 5. 1 and 8. 6 minutes, respectively, and the run time was 11 minutes. The percent recoveries (mean±SD) of lycopene and beta-carotene were 95. 5%±7. 8 and 95. 2±7. 0, respectively, and their intra- and inter- measurement variations 1. 6% and 5. 75% and 3. 0% and 3. 5%, respectively Quality control tests indicated high sensitivity and precision of the method. The method is quite suitable for use in research and, particularly, in population studies, although it has, like any other method, its own limitations. Furher studies are needed in this area.