ANALYSIS OF CAROTENOIDS BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY AND SUPERCRITICAL FLUID CHROMATOGRAPHY

The first part of this paper describes the chemical structures and the importance of carotenoids for health. Sample preparation for extracting the carotenoids from fruits and vegetable matrices is detailed in terms of pre-extraction treatment (enzyme inactivation. addition of antioxidants and acid neutralizers), extraction conditions with solvents or supercritical fluids and saponification. In the second part, HPLC and SFC separation methods are described. The efficiencies of different inorganic packings (silica, magnesium oxide, calcium hydroxide, alumina), bonded silica packings (cyano, octadecyl) and chiral phases (cellulose, cyclodextrins) are discussed. The choice of an appropriate method depending on the type of pigment to be separated (xanthophylls, catotenes, cis-trans isomers) is discussed. The effects of the mobile phase (specific interactions, hydrogen bonding) and of the stationary phase (nature and type of linkage: monofunctional or polyfunctional, end-capping of residual silanols) on the solute retention are reported and explained on the basis of the differences between the chemical structures of the pigments.