The surface pressure-area isotherms of all-trans retinal, 9-cis retinal, 13-cis retinal, all-trans retinol and all-trans retinyl acetate at air/water interface have been studied. The spectroscopic studies of the monolayers of the pigments are also discussed. The monolayers were first compressed to the required surface pressure and were then transferred to air-quartz and air-lipid interfaces. The spectra of monolayers of isomeric retinals show a red shift of 15 ± 1 nm as compared to their solution spectra, whereas the monolayers of trans-retinol and retinyl acetate show a blue shift of 35 ± 2 nm relative to their solution spectra. These shifts have been explained on the basis of exciton model. The deposition of multilayers of trans-retinol and retinyl acetate has also been achieved and the optical density is found to vary linearly with the number of layers.
ASJC Scopus subject areas
- Sensory Systems