Reversed-phase gradient high-performance liquid chromatographic procedure for simultaneous analysis of very polar to nonpolar retinoids, carotenoids and tocopherols in animal and plant samples.

A reversed-phase gradient high-performance liquid chromatographic (HPLC) procedure, which utilizes gradient elution and detection by a photodiode-array detector, has been developed to analyze simultaneously very polar retinoids, such as 4-oxo-retinoyl-beta-glucuronide, retinoyl beta-glucuronide and 4-oxo-retinoic acid; polar retinoids, such as retinoic acid and retinol; nonpolar retinoids, such as retinyl esters; along with xanthophylls, monohydroxy carotenoids, hydrocarbon carotenoids, and tocopherols. The procedure has been applied to the simultaneous analysis of retinoids, carotenoids, and tocopherols present in human serum and liver, rat serum and tissues, and for carotenoids in a number of fruits and vegetables. Bilirubin present in human serum can also be simultaneously analyzed. By this gradient HPLC procedure, 3.4-didehydroretinyl ester (vitamin A2 ester) has been identified as a minor constituent in a human liver sample. Lycopene was identified as a major carotenoid in one specimen of papaya fruit, and 5,6,5',6'-diepoxy-beta-carotene was characterized as a major carotenoid in one specimen of mango fruit.