Separation of pairs of C-24 epimeric sterols by glass capillary gas liquid chromatography.

Paris of C-24 epimeric sterols have been very difficult to separate by physical emthods. We report here the partial or complete separation of the trimethylsilyl ethers of nine pairs of C-24 epimeric sterols by gas liquid chromatography on a glass capillary column coated with SP-2340. The trimethylsilyl ethers of the epimeric pairs of sterols with saturated side chains and a pair with two double bonds in the side chain were completely separated from each other by GLC. The epimeric pairs with a double bond at C-22 showed partial separation. The 24β-epimer with a saturated side chain eluted before the corresponding 24α-epimer. This order was reversed for pairs of C-24 epimeric sterol trimethylsilyl ethers containing a double bond in the side chain at C-22.