Abstract
The concentration of vitamin A in the benzene layer, described in the previous report, was found to depend upon the volume of water used for the separation of the benzene layer in the extraction process of unsaponifiable matters. A constant volume of benzene together with vitamin A palmitate was shaked with various volumes of ethanol and water, and the concentration of vitamin A palmitate in the benzene layer was observed. When the ratio of ethanol : benzene : water was 20 : 50 : 20 and 50 : 50 : 100,the concentration of vitamin A palmitate was 1.1 and 3.3% higher than the initial concentration, respectively. The use of 20 ml of ethanol and 40〜80 ml of water, when 50 ml of benzene was used, gave the best results for constancy of the concentration of vitamin A palmitate in the benzene layer. However, when 50 ml of ethanol was used, a large quantity of water or benzene was necessary to be employed. The use of 20 ml of ethanol, 50 ml of benzene and 60 ml of water gave assay values similar to those obtained by the J.P. VII method for several kinds of preparations.
