GAS-CHROMATOGRAPHIC SEPARATION OF BILE-ACID 3-GLUCOSIDES AND 3-GLUCURONIDES WITHOUT PRIOR DECONJUGATION ON A STAINLESS-STEEL CAPILLARY COLUMN

A method for the gas chromatographic (GC) separation of the 3-glucosid e and 3-glucuronide conjugates of bile acids without the necessity for a hydrolytic step is described. The bile acid glycosides were derivat ized to their complete methyl ester trimethylsilyl (Me-TMS) or methyl ester dimethylethylsilyl (Me-DMES) ether derivatives, which in turn we re chromatographed on an inert and thermostable stainless-steel capill ary column, Ultra ALLOY-1 (HT), coated with a thin film (0.15 mu m) of chemically bonded and cross-linked dimethylsiloxane. They exhibited a single peak of the theoretical shape without any accompanying peaks d ue to thermal decomposition, even at oven temperatures of 320-330 degr ees C. Excellent GC separation of isomeric bile acid glycosides was ac hieved by the combined use of suitable derivatives and column. This me thod, which does not need the prior deconjugation of the glycosidic mo iety, could be usefully applied to biosynthetic and metabolic studies of bile acids in biological materials.