抄録
Studies on the determination of fatty acid esters of ascorbic acid (AsA) contained in oily preparations were made. Alkaline solution is usually used for hydrolysis of the esters of fatty acid, however, it was not suitable for the determination of fatty acid esters of AsA, because oxidation of AsA was enhanced during the hydrolysis. But the decomposition of AsA was also observed during the hydrolysis with concentrated acids. Ascorbic acid monostearate (AsA-MS) or ascorbic acid dipalmitate (AsA-DP) was found to be completely hydrolysed in 2% hydrochloric acid in ethanol. The hydrolysate of esters showed blue color by 2-nitro-4-methoxyaniline method as well as AsA. AsA-MS itself also showed the color without hydrolysis. Using this method, 95% recovery was obtained for AsA-DP in a vanishing cream.
