Liquid chromatographic separation of bile acids.

The recent revival in interest in the role of bile acids in biological systems has emphasised the importance of analysing individual bile acids for the presence of closely related impurities. An assessment of the value of modern, high-performance liquid chromatography for this application has shown that mixtures of underivatised bile acids may be resolved by reversed-phase chromatography. Separation of isomeric acids and those differing in the extent of hydroxyl substitution is possible by this approach. Mixtures of amino acid conjugates of bile acids may also be resolved by this method. The use of an ultraviolet absorbance detector, operating at a wavelength in the region of 210 nm, results in a detection limit in the order of 50 ng.