Simultaneous determination of retinol and retinyl esters in serum or plasma by reversed-phase high-performance liquid chromatography

Abstract

The authors propose a single-run liquid-chromatographic determination, with ultraviolet detection at 330 nm, for serum retinol and retinyl esters. The vitamin A derivatives are extracted according to the Bligh-Dyer procedure. With 200 μl of serum, the lower detection limit is 50 μg/liter for retinol and about 100 μg/liter for retinyl esters. Within-run precision (CV) was 2.3% for retinol, 4.3% for retinyl palmitate. Day-to-day precision (CV, n=20) for retinol was 4.9% in the course of a month. The method can be used for the assessment of vitamin A absorption tests and for the determination of serum retinol (normal, subnormal, and above-normal concentrations). Serum retinyl esters can only be measured in conditions where concentrations exceed 100 μg/liter.