A direct method for the separation and quantification of bile acid acyl glycosides by high-performance liquid chromatography with an evaporative light scattering detector

A direct method for the separation and quantification of a series of bile acid acyl glycosides using high-performance liquid chromatography coupled to an evaporative light scattering detector (HPLC–ELSD) is described. Complete separation of each of 15 bile acid acyl 24-α-glucosides and their 24-β-anomers and 24-β-galactosides was achieved by the stepwise gradient elution mode on a C18 column using a mixture of acetonitrile–methanol (8:2, v/v) and 1% aqueous acetic acid as the mobile phase. 24-β-Galactosides were always eluted faster than the corresponding 24-β-glucosides, which eluted after the corresponding 24-α-anomers. Calibration curves of different 24-β-galactosides were linear over a range of 0.2–40 nmol of injected amount and the detection limits (S/N > 3) were from 0.08 to 0.1 nmol. The present HPLC–ELSD method may provide an insight into the separation and quantification of the biologically interesting neutral bile acids.