Abstract
Saponification, extraction of unsaponifiable matter, precipitation of steroid, followed by single chromatography through a column, packed with partially activated Superfiltrol Grade No. 19,separates vitamin D quantitatively from other components, especially 10〜20 fold of synthetic vitamin A, thus leads to a simple and practical determination of vitamin D in commercial multivitamin preparation. But, when natural vitamin A concentrate, a practical source of this vitamin so far, is used, some unknown substance in its unsaponifiable fraction often causes overestimated result. Because such unknown substance shows rather simillar behavior to vitamin D in its adsorptivity and color reaction. Nevertheless, interference due to such substance can be eliminated practically by using the corrected E_<500mμ> value. E_<500mμ>(corrected)=E_<500mμ>(uncorrected, 120 seconds after addition of SbCl_3)-E_<500mμ>(120〜130 seconds after addition of SbCl_3) Experimental error is found to be 5% or less. Detailed report will be published later.
