Abstract
Vitamin A aldehyde is stable in the alkaline solution at low temperature, but the aldehyde was decomposed by heating with alkali, yielding a large amount of decomposition products, in which a trace of a compound considered to be vitamin A alcohol was detected. It is assumed, therefore, that not only the estimation but also the identification of vitamin A aldehyde are impossible when the aldehyde treated under the similar condition was used for the hydrolysis of vitamin A esters. The isomerization of vitamin A aldehyde was resulted even at room temperature when the aldehyde was treated with alcoholic hydrochloric acid. The substance showing the absorption spectra corresponding to those of anhydrovitamin A and some of other oxidized products are also formed in the above alcoholic hydrochloric acid solution upon heating. Vitamin A aldehyde is comparatively stable under day light, a fluorescent lamp, or quartz-mercury lamp, but this substance was gradually oxidized in process of hours of exposure. For the decomposition activities of these irradiation, the quartz-mercury lamp has the strongest, followed by the fluorescent lamp, and day light was the weakest in activity.
