Simultaneous quantification of retinol, retinal, and retinoic acid isomersby high-performance liquid chromatography with a simple gradiation

A new method of high-performance liquid chromatography (HPLC) analysis to q uantify isomers of retinol, retinal and retinoic acid simultaneously was es tablished. The HPLC system consisted of a silica gel absorption column and a linear gradient with two kinds of solvents containing n-Hexane, 2-propano l, and glacial acetic acid in different ratios. It separated six retinoic a cid isomers (13-cis, 9-cis, all-trans, all-trans-4-oxo, 9-cis-4-oxo, 13-cis -4-oxo), three retinal isomers (13-cis-, 9-cis-, and all-trans) and two ret inol isomers (13-cis- and all-trans). Human serum samples were subjected to this HPLC analysis and at least, all-trans retinol, 13-cis retinol, and al l-trans retinoic acid were detectable. This HPLC system is useful for evalu ating retinoic acid formation from retinol via a two-step oxidation pathway . Moreover, it could he applied to monitoring the concentrations of various retinoids, including all-tuans retinoic acid in human sera. (C) 2001 Elsev ier Science B.V. All rights reserved.