| Abstrakt: |
In this report we describe a modified reverse phase HPLC method that avoids the solvent evaporation step and allows simple and rapid determination of retinol, α-tocopherol, α-carotene and β-carotene and achieves complete separation of α- and β-carotene. Retinyl acetate, α-tocopheryl acetate and retinyl palmitate in ethanol were added to serum as internal standards. Serum was then deproteinized with an equal volume of ethanol, and the lipid was extracted with ethyl acetatebutanol (1:1 v/v). A portion of this solution was injected into a C18 reverse phase chromatographic column and absorbencies of the vitamins and internal standards were measured at 292 nm for tocopherols, 325 nm for retinoids and 450 nm for carotenoids; peakheight ratios were used to quantify each vitamin. The analytical recoveries for retinol, α-tocopherol α- and β-carotene at various concentrations tested were 95103, 9098, 9299 and 9496%, respectively. The intra- and interassay variations for low and high concentrations of retinol, α-tocopherol, α- and β-carotene ranged from 2.4 to 6.7 for intraassay and from 4.3 to 8.5 for interassay replication. The detection limits were 1.25 (0.04), 19 (0.44), 0.35 (0.006) and 0.94 (0.017) μg/dL (δmol/L) for retinol, α-tocopherol, α- and β-carotene, respectively. © 1998 John Wiley & Sons, Ltd. |
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