Studies on the reaction of certain carotenoids with antimony trichloride.
نویسندگان
چکیده
Since both carotene and vitamin A yield a blue color with SbCla, attempts to determine t,he vitamin quantitatively in a mixture depend, among other things (1, 2)) upon the accuracy with which the blue color due to carotene can be estimated. Values published for the blue equivalent of carotene range from 3.5 to 13, calculated as micrograms of apparent vitamin A per 100 y of carotene (3). This discrepancy does not result in serious errors in the analysis of mixtures relatively rich in vitamin A, but in materials such as eggs, concentrates for animal feeding, or aliquots of mixed human diets the blue color from carotenoids may constitute a major fraction of the total absorption, and hence the proper evaluation of this component becomes critical. The color due to vitamin A reaches maximum intensity in 2 to 5 seconds after the addition of a SbC13 reagent (4), whereas that from the carotenoids forms more slowly (5-7) and varies with the pigment. Concentrates from summer butter have been observed to react more slowly than those from winter butter (8). The present study deals with variations in the intensity and rate of formation of the blue color when SbC& reacts with derivatives of carotene. It has been recognized that extraction and saponification procedures normally employed in analyses may result in either an oxidation or isomerization of the pigment (9-12).
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عنوان ژورنال:
- The Journal of biological chemistry
دوره 169 1 شماره
صفحات -
تاریخ انتشار 1947