EXPERIMENTS ON THE USE OF SILICIC ACID FOR STEROID CHROMATOGRAPHY

Abstract

Mixtures of pure sterols, and extracts of hydrolyzed urine, were chromatographed on columns of silicic acid. The results were observed spectrometrically using a sulphuric acid – methanol color reagent. Dry silicic acid retained or altered the sterols. When the silicic acid contained free water the sterols were distributed between the surface of the solid and the developing solvent. The adherence to the solid phase decreased with increase of free water and with increased solubility of the sterol in the solvent. As the free water was increased liquid–liquid partition was observed. The adherence of the sterol to the silica surface increased with the number of hydroxyl groups in the sterol molecule. Silicic acid columns are therefore particularly suited to the separation of sterols that differ in their number of hydroxyl groups and to the detection of the production of artifacts by loss of the hydroxyl group.