Adsorption experiments with vitamin A concentrates

Abstract

Chromatographic analysis of rich vit. A concentrates controlled by spectroscopic examination of their alcohol solutions and of their SbCl3 blue colors shows that 5 main fractions may be obtained. In order of adsorption on alumina or Ca(OH)2 they are:[long dash](a) Strongly adsorbed material giving a violet or violet-blue with SbCl3, probably largely vit. oxidation products. (b) The main fraction, consisting of highly conc. vit. A characterized by a 328 m[mu] absorption band, and corresponding to Karrer''s so-called [beta]-vit. A. (c) A small amt. of strongly colored red material, apparently produced by polymerization from the vitamin during adsorption, and with a band at 328 m[mu] and a smooth inflexion near 430 m[mu]. Mol. wt. detns. suggest that it contains polymerized material. (d) A small amt. of the so-called [alpha]-vit. A (hepaxanthin) of Karrer et al., which shows an absorption max. at 270-280 m[mu], is probably another decomposition product of vit. A. (e) A very small amt. of a bright yellow substance with 3 absorption bands at 348, 369, and 389 m[mu].