Ferric chloride impregnated silica gel for thin layer chromatography of steroids

Abstract

Silica gel G is mixed with an aqueous solution of ferric chloride, and the resulting slurry spread onto glass plates. After spotting, development, and drying, the plates are sprayed with sulfuric acid. Cholesterol, ergosterol, and Δ5 pregnen 3β ol 20 one produce colored spots (pink violet, greenish black, and pink violet, respectively) without further treatment, but some other steroids require heating at 70°C for full color development. Other colors generated are: estrone, orange; Δ4 androsten 3,17 dione, blue green; androsterone, light brown; and 5α androstan 17β ol 3 one, tan. After prolonged heating at 70°C, 6 keto cholestanol produces an orange brown spot. Color reactions are more reproducible than they are when the ferric chloride is sprayed on the plate.