Separation and identification of geometric isomers of 3-hydroxyretinoids and occurrence in the eyes of insects

The 9-cis, 11-cis, 13-cis and all-trans isomers of 3-hydroxyretinal oxime, and the 11-cis, 13-cis and all-trans isomers of 3-hydroxyretinol have been resolved by high pressure liquid chromatography (HPLC) and identified by their spectral properties. The antimony chloride reaction product of 3-hydroxyretinol is spectrally indistinguishable from that of retinol. Heads of insects from 8 genera of Diptera and Lepidoptera were found to contain 3-hydroxyretinoids. The most abundant isomers of 3-hydroxyretinal are 11-cis and all-trans.