APPLICATION OF THIN-LAYER CHROMATOGRAPHY USING SILICA GEL WITHOUT BINDER TO THE IDENTIFICATION OF STEROIDS

The thin-layer chromatography using silica gel without binder for rapid identification of steroids is described. The advantage of the present method over that using alumina thin-layer without binder is its precise resolving power, and in comparison with the thin-layer of silica gel with binder, it possesses the additional advantages of simplicity and speed. The spots on the thin-layer can easily be detected with the reagent by impregnating one side of the thin-layer perpendicular to the developing direction. The spots or zones can also be de- tected by impregnation with only a simple solvent in which the compounds to be iden- tified are insoluble. The specifications and reagents used in the present investigation are as follows: Silica gel for chromatography: 18-250 mesh and below 250 mesh; grade Ⅰ/Ⅱ. Dimensions of thin-layer; 120×60×0.6mm. Solvents for development: benzene-Ethyl acetate (7:3, 5:5, 4:6, 1:9). Reagents for detection: (1) aqueous solution of 3% phosphomolybdic acid; (2) aqueous solution of 2,4-dinitrophenylhydrazine. A series of 20 steroid compounts are chromatographed on the thin layer of silica gel without binder.