Simultaneous high-performance liquid chromatographic determination of retinol by fluorometry and of tocopherol by ultraviolet absorbance in the serum of newborns.

The simultaneous determination of retinol and tocopherol by isocratic HPLC in 100 microl serum from preterm newborns is described. Retinol (tR 2.02+/-0.04 min) and retinyl acetate were detected fluorometrically, and were baseline-resolved in 4 min. Tocopherol (tR 8.4+/-0.16 min) and tocopheryl acetate were detected by UV absorbance. Intra- and inter-assay RSD were: retinol, 5.6 and 8.1, and tocopherol, 3.6 and 6.7, respectively. This method is fast, selective and highly sensitive for retinol. It permits the measurement of serum concentrations of retinol and tocopherol with good accuracy and precision.