A ROUTINE METHOD FOR THE SIMULTANEOUS MEASUREMENT OF RETINOL, ALPHA-TOCOPHEROL AND 5 CAROTENOIDS IN HUMAN PLASMA BY REVERSE-PHASE HPLC

We describe a simple isocratic HPLC method for the accurate and precis e measurement of retinol, alpha-tocopherol and the major carotenoids i n plasma using UV detection. Reference ranges for retinol, alpha-tocop herol and five carotenoids are determined in a healthy population grou p. The most abundant carotenoids found in plasma were beta-carotene, l ycopene, lutein and cryptoxanthin. Retinol, alpha-tocopherol and carot enoids were determined simultaneously using two internal standards, re tinol acetate for retinol and tocopherol acetate for alpha-tocopherol and carotenoids. The use of echinenone as an internal standard for car otenoids was investigated. The protective effect of an antioxidant (as corbic acid) on the stability of samples and extracted material is doc umented. The method is useful for the routine measurement of plasma re tinol, alpha-tocopherol and carotenoids and could also be used in larg e scale epidemiological studies. (C) 1998 Elsevier Science B.V.