A Test to Differentiate Irradiated Cholesterol From Non-Irradiated Cholesterol and Irradiated Ergosterol From Non-Irradiated Ergosterol.

Abstract

Cholesterol dissolved in chloroform gives with a mixture of sulphuric and selenious acids (125 mg. of sodium selenite in 25 cc. of concentrated sulphuric acid) a purple color in the upper chloroform layer and a red-brown color in the lower acid layer, which displays no green fluorescence. Solid cholesterol, irradiated with the mercury arc lamp for 30 minutes at a distance of 16 inches, when dissolved in chloroform gives with the sulphuric and selenious acid mixture a dark wine-red color in the chloroform layer, and a still darker wine-red color in the acid layer with the absence of green fluorescence. This reaction takes place in the 1.0% and in the 0.5% solution. In the 0.25%, 0.10%, 0.025% and 0.01% solutions the color reaction is negative. The chloroform layer is more or less purple, while the acid layer is brown and free from fluorescence. Ergosterol, non-irradiated and dissolved in chloroform, gives with sulphuric acid a colorless chloroform layer and a brownish red, cherry red or orange color in the acid layer in direct light and a green fluorescence in transmitted light. With the sulphuric acid-selenious acid mixture the chloroform layer also remains uncolored, while the acid layer gives a brown color in direct light and no green fluorescence in transmitted light. Solid ergosterol, irradiated with the mercury lamp for 30 minutes at a distance of 16 inches, dissolved in chloroform and treated with sulphuric or sulphuric-selenious acid, gives a greenish blue color in the chloroform layer in the 1.0% and in the 0.5% solution. The acid layer, however, does not differ in color from that obtained with non irradiated ergosterol. In the 0.25%, 0.1%, 0.025% and 0.01% solutions of irradiated ergosterol the color responses were the same as those obtained with the same concentrations of non-irradiated. ergosterol.