Abstract
For detemining vitamin D in liver oil, the majority of steroids is removed by precipitating in methanol cooled with dry ice, and the vitamin is determined 15 seconds after adding antimony reagent containing acetyl chloride, whereby no effect of a slight amount of steroids remaining is observed. The procedure is thus remarkably simplified. Vitamin D in the eluate from alumina chromatography seemed to have changed into some other substance of a different absorption maximum without losing the recovery of the vitamin activity. Vitamin A is likewise shown to undergo a partial change, appearing partially in the vitamin D fraction in alumina chromatography. Therefore in those cases, where much vitamin A is present together with a small amount of vitamin D, the effect of vitamin A is unavoidable.
