A reversed-phase high-performance liquid chromatographic method to analyzeretinal isomers

A high-performance liquid chromatographic (HPLC) procedure was developed to separate all-trans-, 13-cis-, 11-cis- and 9-cis-retinal isomers. Two rever sed-phase Vydac C-18 columns in series were used with an isocratic solvent system of 0.1 M ammonium acetate-acetonitrile (40:60, v/v) as mobile phase and all-trans-9-(4-methoxy-2,3,6-trimethylphenyl)-3,7-dimethyl-2,4,6,8-nona tetraene-1-ol (TMMP) as internal standard. Prior to HPLC, the retinal isome rs were efficiently extracted in their original isomeric conformation using dichloromethane-n-hexane in the presence of formaldehyde. This technique i s suitable for the assay of 11-cis- and all-trans-retinal isomers in retina . (C) 1999 Elsevier Science B.V. All rights reserved.