Abstract
Eight kinds of commerical acid clays were tested. They were dried at 105-110℃, packed in a chromatographic column, 6 cm in height and 0.7 cm in diameter, and washed preliminarily with 15 ml of 7% ethanol-hexane (using 96% ethanol) followed by 10 ml of 10% ethyl ether-hexane. Four out of the eight clays gave good results. In the chromatography using one of these activated acid clays, four kinds of developing solvent systems (n-hexane, carbon tetrachloride, benzene, 10% ethyl ether) were tested. The recoveries of added vitamin D_2 were better when n-hexane and 10% ethyl ether-hexane were used then carbon tetrachloride and benzene were used. When n-hexane alone was used as a developing solvent, vitamin D_2 was present in the 4-50 ml of the effluents. The amount of vitamin A which could be introduced onto the column was found not to exceed 7,000-8,000 I.U.
