抄録
A simple colorimetric method for vitamin D is described, whereby steroids in the unsaponifiable matter are precipitated with cooled methanol and vitamin A is removed by superfiltrol chromatography. Vitamin D is photometerically determined soon after adding antimony reagent. In the presence of more than 500μg of vitamin A, the correction for it is necessary. The limitation of this method for concentration ratio of A/D in I.U. is markedly higher than that of alumina method, the optimum limit of A/D of the former being 20 (but is roughly determinable even at the ratio of 1000), whereas that of the latter about 0.8. In cases, where A/D is below 4,the values of liver oils determined by both methods agree well, but when A/D is above 46,the values with alumina method are remarkably higher than those with superfiltrol method, the former method being distinctly influenced by impurities.
