Improvements in the separation of beta-carotene and lycopene by column chromtography

Abstract

Improvements in the Separation of /3-Carotene and Lycopene by Column ChromatographyAn excellent experiment for demonstrating column chromatography is the separation of /3-carotene and lycopene in carrot and tomato paste, respectively. The following is a modification of the experiment as written in Fieser and Williams.1 Three grams each of carrot and tomato paste were placed in a beaker with 15 mL of 95% ethanol.2 The mixture was well stirred with a glass rod for several minutes and filtered using vacuum filtration, and the residue was pressed with another piece of filter paper to get out as much liquid as possible. The alcohol extract was discarded and the dehydrated residue was placed in a 50-mL flask along with 10 mL of dichloromethane.3 The mixture was refluxed for 5 min and then filtered using vacuum filtration. The residue was returned to the flask and the procedure was repeated twice more. The dichloromethane extracts were combined, washed once with saturated sodium chloride solution, dried over sodium sulfate, and evaporated to dryness. The oily residue was taken up in 2 mL of low-hoiling petroleum ether.4 A 150 X 11-mm column of activity I alumina was prepared using low-boiling petroleum ether. The carotanoid mixture was applied to the alumina column in a narrow band using petroleum ether to wash down the sides of the column. After several milliliters of petroleum ether were passed through the column (the carotanoids should remain in a narrow band at the top of the column), the solvent was changed to 10% diethyl ether-petroleum ether. The /3-carotene separated as a distinct yellow band from the orange lycopene. Once all the /3-carotene was eluted off, the solvent was switched to 50% diethyl ether-petroleum ether in order to elute off the lycopene. The solvent was evaporated from the two fractions and approximately 0.2 mL of dichloromethane was added to each residue. Thin-layer chromatography was done using silica gel plates and 5% chloroform-cyclohexane as the eluting solvent. The /3-carotene gave a distinct yellow spot with an Rf of 0.4, and lycopene gave an orange spot with an /?f of 0.2. This experiment requires about 3.5 h.

Topical Delivery of Lycopene using Microemulsions: Enhanced Skin Penetration and Tissue Antioxidant Activity

“…Lycopene was extracted from commercial tomato paste as previously described 15, 16. Because lycopene is easily degraded, samples were protected from light and heat.…”

Microscale yeast mediated enantiospecific reduction of vanillin, and the absolute configuration of (-)-(R)-[alpha]-deuteriovanillyl alcohol: A bioorganic chemistry experiment

“…Literature Cited Experiments for the isolation and analysis of carotenoids from carrot and/or tomato pastes are popular in instructional chemistry laboratories (1)(2)(3)(4)(5) but often require 3.5-5 h. We have developed an experiment for the isolation and separation of fS-carotene and lycopene from tomato paste on the microscale level that affords the isolation of two compounds from a single common foodstuff and requires less than 3 h to complete. The compounds can be rapidly analyzed.…”

Analytical and Preparative Chromatography of Tomato Paste Carotenoids

“…A modified version of the extraction method was used (Ronman, 1985). Tomato paste (150 g) was stirred vigorously with 750 mL ethanol (95%) followed by vacuum filtration.…”