Sensitive Analysis of Retinyl Esters by Isocratic Adsorption Chromatography

Summary: A sensitive method for the determination of retinyl esters, including their geometric isomers, by isocratic adsorption HPLC is described. The development of a special recycling System allows the Separation of all-trans-, 13-ciy, \\-cis- and 9-ctf-retinyl palmitate,-stearate,-oleate,-palmitoleate and-linoleate with short retention times and high sensitivity. Extraction of the retinyl esters from various organs with mobile phase avoids additional evaporation Steps. The method was evaluated by the determination of retinyl esters in small tissue samples such äs tongue, trachea and inner ear. This is the first report of the detection of retinyl esters in these tissues, which are known tp depend on an adequate vitamin A supply. The main ester in all cases was retinyl palmitate, followed by retinyl stearate and oleate