A proposed method of analysis for vitamin A acetate and vitamin A palmitate bulk

An ethyl acetate solution of Vitamin A Acetate and Palmitate can be determined calorimetrically with the addition of concentrated hydrochloric acid in the proper ratio; one part of ethylacetate-Vitamin A solution to four parts of acid. A purplish-blue color is produced which reaches its maximum intensity within one minute and lasts for ten minutes. This color can be read in the Ilett-Summerson colorimeter using glass filter #54. Like many colorimetric determinations, this method is valid within certain concentration limits of sample, 20-225 milligrams of Vitamin A per final 5 milliliter aliquot