抄録
After thorough examination of the fundamental conditions of color reaction, chromatography and removal of the effects of inter-mingled carotenoids and steroids, we succeeded in determining chemically the vitamin D value of liver oil, the procedure of which was described in detail.
Of the fundamental conditions the following facts were confirmed by our studies.
The maximal absorption of the colored reaction product lies at about 500 mμ. E value is dependent of the concentration of antimony trichloride, 200 mg./ml. being the most adequate. After addition of the reagent the E value rises to a maximum and then decreasing gradually.
The time arriving to the maximum is dependent of the tempera-ture. The maxium E values are propotional to the amount of D, within 10μg. Using activated alumina “BL6” as an adsorption column and 10% acetone in petroleum benzine as a developing solvent, the separation of A and D is practically complete, as long as the amount does not exceed 50μg. As intermingled peroxide in solvent destroys vitamin D, it must be removed previously, if the reagent is not free from it.
A specific pigment “X” could be isolated fom red pepper, which behaves chromatographically in the same way as vitamin A and it makes possible to observe the position of vitamin A. By the treat-ment of maleic anhydride in dioxane, vitamin D remains unchanged by heating at 80°C for 10 minutes but is destroyed completely by heating at 100°C for 30 minutes. Carotenoids and steroids are destroyed considerably by heating at 80°C for 10 minutes but the destruction does not go further after heating at 100°C for 30 minutes. The difference of the extictions after heating at both conditions agree quite well with the extinction of added vitamin D alone. The added vitamin D is practically completely recovered throughout the whole treatment.
