Determination of nine carotenoids, retinol, retinyl palmitate and α-tocopherol in control human serum using two internal standards

In the determination of the carotenoids in 39 samples of human serum from Spanish control subjects, those most abundant were found to be β-cryptoxanthin, lycopene, lutein and β-carotene; the least abundant carotenoids were zeaxanthin and α-carotene. Lutein and zeaxanthin, when analysed separately, were present at a ratio of about 3:1 in all the sera studied. One xanthophyll, identified as canthaxanthin, was detected in all serum samples. Other carotenoids, such as γ-carotene and β-apo-8′-carotenal, were found in only some of the samples. Retinol and α-tocopherol were determined simultaneously, as was the tocopherol/cholesterol ratio. Retinyl palmitate was measured in only one of the control subjects, although its elution produced no interference with β-carotene or cis-β-carotene. As internal standards, retinyl acetate was used for retinol and tocopherol acetate for α-tocopherol and the carotenoids.This investigation was partially funded by grant 89/0110 from the Fondo de Investigaciones Sanitarias (FIS), Spain.Peer reviewe