Preformed Vitamin A in Mixed Feeds

Vitamin A in Mixed Feeds

“…The presence of appreciable amounts of vitamin A alcohol such as might be provided by a saponified fish oil concentrate, can be detected readily by comparison of the apparent vitamin A content after complete elution of the carotene with the amount of vitamin A ester eluted prior to the carotene. In agreement with Narod and Verhagen (5) oxidation products of vitamin A are retained by magnesia (Table VI).…”

“…at the stage of analysis contained the quantity of material shown in Table I. To each portion analyzed, 5 ml. of the Folin-Denis reagent and 10 ml.…”

Pharmaceuticals and Natural Drugs

“…Rice et al (206) have discussed the present status of the antimony trichloride procedure. Practically quantitative separation of vitamin A from its oxidation products and from carotenoids is reported by Narod and Verhagen (174), using a magnesia-Celite adsorption column. Paper chromatographic techniques have been applied to the separation of vitamin A in mixtures by using filter paper impregnated with alumina (65).…”

Food

“…Methods have been described for the determination of the vitamin A-active pigment, carotene, itself (63,147,SOI,373) in alfalfa and similar grasses, and together with preformed vitamin A in mixed feeds (86,265). By the appropriate choice of the developing solvent it has been found possible to separate ßcarotene from certain of its stereoisomers (31).…”