SEPARATION OF EPIMERIC PAIRS OF C-24 ALKYLSTEROLS BY REVERSED-PHASE HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY OF THE FREE STEROLS AT SUBAMBIENT TEMPERATURE

Separation of most of the common biologically occurring epimeric pairs of C-24 alkylsterols was obtained by reversed-phase HPLC of non-derivatized free sterols at subambient temperatures. Base line separation occurred in most cases with an analysis time frequently as rapid as 30 minutes with a solvent system of methanol and isopropanol. Several pairs of C-24 ethylsterols were separated poorly by this system but were satisfactorily resolved with a mobile phase of methanol, although analysis times were as long as 90 minutes. A method was also developed for concurrent resolution of important metabolic intermediates in cholesterol metabolism: cholesterol, desmosterol, lathosterol, and 7-dehydrocholesterol.