Characterization of bile acid methyl ester acetate derivatives using gas-liquid chromatography, electron impact, and chemical ionization mass spectrometry.

The gas-liquid chromatographic retention times on 0.5% SP-525 for 48 bile acids and related compounds as their methyl ester acetate derivatives are given. Ion tables for electron impact spectra have been compiled that permit direct access to ion structures for any given ion mass. Chemical ionization yields highly simplified mass spectra with two or three ions predominating for each compound. When the relative retention times of bile acids as their methyl ester acetates are combined with selective ion monitoring techniques in chemical ionization mass spectrometry, the retention time and ion mass number form a coordinate system which can be a powerful tool in the characterization of bile acid mixtures.