Separation of steroids by countercurrent chromatography using supercritical fluid carbon dioxide

Since the introduction of the modem apparatus and technology of countercurr ent chromatography (CCC), researchers have found numerous applications in t he analyses and preparations of natural products. Selection of appropriate solvent systems is a basic and important task for separation in CCC. Recent ly, we provided an alternative choice of the solvent system by replacing th e liquid mobile phase with supercritical-fluid carbon dioxide (SFCO2). In t his work, three steroids - progesterone, Delta(4)-androstene-3,17-dione, an d (+)-4-cholesten-3-one were separated as test compounds using SFCO2 as the mobile phase and methanol-water (30/70 v/v) solution as the stationary pha se.