A Colorimetric Method for Determination of Vitamin A and Carotene by Perchloric Acid.

Abstract

A method is described for the quantitative colorimetric estimation of vit. A and carotene in each other''s presence. The method is based on the fact that the purple-red color developed by vit. A (max. absorption 525-530 m[mu]) and the bluish-green color developed by carotene (max. . absorption 725-760 m[mu]) in the presence of perchloric acid, may be stabilized in a soln. of amyl acetate. In a mixture of vit. A and carotene, carotene may be estimated directly by determining its absorption at 750 [mu]; the amts. of vit. A may be calculated by subtracting from the absorption, measured at 525 m[mu], the absorption value which corresponds to carotene at this wave length.