Reagents Carr-Price

Water-Soluble Annatto Extracts Transfer 2 mL or 2 g of sample into a 50-mL separatory funnel, and add sufficient 2 N sulfuric acid to make the solution acidic to pH test paper (pH 1 to 2). Dissolve the red precipitate of norbixin by mixing the solution with 50 mL of toluene. Discard the water layer, and wash the toluene phase with water until it no longer gives an acid reaction. Remove any undissolved norbixin by centrifugation or filtration, and dry the solution over anhydrous sodium sulfate. Transfer 3 to 5 mL of the dry solution to the top of an alumina column prepared as described above. Elute the column with toluene, three 10-mL volumes of dry acetone, and 5 mL of Carr-Price Reagent (see Solutions and Indicators) added to the top of the column. The orange-red band of norbixin immediately turns blue-green. 

Compound 2, m.p. 134 - 135°C, showed a M at m/e 414. The NMR, UV, and JR spectra suggested the presence of a steroid. The color reactions developed with the Liebermann-Burchard and Carr-Price reagents were also in accord with a steroid structure. Compound 2 was identified as sitosterol by comparing its m.p. and NMR, IR, UV, and MS spectra data with those of an authentic sample (Aldrich Chemical Company, Inc., Milwaukee, WI). 

Antimony(ni) chloride (Carr-Price reagent) for vitamins A and D, carotenoids, steroid sapogenins, steroid glycosides and terpene derivatives. 

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