An improved gas-chromatographic method for the determination of sulfated and unsulfated bile acids in serum

This study has been aimed at improving some steps in the gas-liquid chromatographic determination of sulfated bile acids. The best conditions for the enzymatic hydrolysis with cholylglycine hydrolase of sulfolithocholylglycine and sulfolithocholyltaurine are described. Recoveries of more than 85% were obtained after prolonging the incubation to 12 h. A single-step procedure for solvolysis and methylation of bile acids was achieved by using, as a water scavenger, 2,2-dimethoxypropane added directly to the hydrolysis mixture. This procedure avoided the difficulty of the extraction of sulfated bile acids from aqueous solutions.