Simultaneous measurement of serum retinol, tocopherols, carotenes, and carotenoids by high performance liquid chromatography

An isocratic, high‐performance liquid chromatography method is presented for the simultaneous analysis of retinol, tocopherols, carotenes, and other carotenoids. The method employs detection at two wavelengths (292 and 450 nm) and three internal standards, which are: retinyl acetate, alpha‐tocopheryl acetate, and retinyl palmitate. The use of the internal standards is important for accurate quantitation, especially to correct for recovery of beta‐carotene. The long‐term (n = 81, over three months) precision of the method ranged from a coefficient of variation of 8.2% for retinol to 16% for lycopene. This assay system provides accurate, precise, and rapid analysis and is suitable for longitudinal and cross‐sectional large‐scale epidemiological studies of these vitamins.