[63] Preparation and assay of cholesterol and ergosterol

摘要: Publisher Summary In preparation of colloidal cholesterol suspension 0.5 g. is added in 10 ml. warm acetone and poured into 100 boiling water with vigorous stirring. Floating particles sediment are filtered. The residual removed by vacuo when it desirable to eliminate this component from the reaction mixtures. Colloidal ergosterol prepared same manner. Cholesterol assayed Liebermann-Bulchard reaction. samples be adjusted 80% (v/v) ethanol-acetone (1:1) deproteinize mixtures extract cholesterol. This conveniently carried out transferring mixture a centrifuge tube rinsing vessel small aliquots ethanolacetone until desired amount has been tube. precipitate extracted approximately vol. for 5 minutes bath (40 50 °) effect complete recovery When completely dry, chloroform pipette each Then 2 cold acetic anhydride-sulfuric acid reagent sample mixed swirling. tubes placed 16 18 ° bath, color allowed develop 15 minutes. blue-green measured immediately at 625 mu compared standard curve over range 0.1 mg. Standards included assay.