title: High-performance liquid chromatography of bile pigments: separation and characterization of the urobilinoids.
abstract: The detailed analysis of faecal bile pigments by high-performance liquid chromatography is described. Non-aqueous reversed-phase systems with acetonitrile-dimethyl sulphoxide or acetonitrile-dimethyl sulphoxide-methanol as the mobile phase on C1, C8 or C18-bonded silica are used for the group separation of verdinoids, violinoids and urobilinoids. A silica column, with acetonitrile-water-tetraethylene-pentamine as mobile phase, separates the laevorotatory stercobilin (C33H46N4O6) and half-stercobilin (C33H44N4O6) from the optically inactive urobilin (C33H42N4O6). The diastereoisomers are resolved by converting the urobilinoids into their dimethyl esters before chromatography on a silica column with n-heptane-methyl acetate-methanol containing 1% of diethylamine as the solvent system.
mesh_terms: D000743:Anemia, Hemolytic / Q000378:metabolism*; D001654:Bile Pigments / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D005243:Feces / Q000032:analysis*; D006801:Humans; D014557:Urobilin / Q000145:classification / Q000302:isolation & purification*
chemical_list: D001654:Bile Pigments; D014557:Urobilin