Simultaneous determination of free and conjugated bile acids in human gastric juice by high-performance liquid chromatography.

A high-performance liquid chromatographic procedure has been developed for the simultaneous assay of the major free bile acids and the corresponding glycine and taurine conjugates in man. No preliminary fractionation into the free, glyco- and tauro-conjugated forms was required. An Ultrasphere ODS column with UV detection at 210 nm and methanol-acetate buffer gradient elution were used. The retention volume of the conjugates was dependent on the sodium acetate concentration in the mobile phase. The method is applicable to the quantification of intragastric bile acids with satisfactory sensitivity, selectivity and precision. Unconjugated and conjugated bile acids present in the gastric juice of patients with bile reflux gastritis were determined directly after Sep-Pak C18 cartridge purification.