title: Determination of dopamine-3- and 4-O-sulphate in human plasma and urine by anion-exchange high-performance liquid chromatography with fluorimetric detection.
abstract: A high-performance liquid chromatographic (HPLC) method is reported for the determination of dopamine-3- and -4-O-sulphate isomers in human plasma and urine using an anion exchanger coupled with post-column hydrolysis and fluorimetric detection. Samples of plasma or urine are partially purified on Dowex 1 and Dowex 50 columns and separated using HPLC. These compounds are then hydrolysed and determined automatically by the p-aminobenzoic acid method in a continuous-flow reaction system. As the p-aminobenzoic acid method is very specific for dopamine, it is also possible to determine the isomers by injecting 5-20 microliter of urine or 100-200 microliter of deproteinized plasma directly into the HPLC system without clean-up. The detection limit of the method for both isomers is 0.3 pmol. In normal subjects, the plasma levels of dopamine-3- and -4-O-sulphate are 26.5 (S.D. 11.1) and 2.68 (S.D. 0.34) pmol/ml, and their urinary excretion rates are 1.73 (S.D. 0.56) and 0.27 (S.D. 0.04) nmol/min, respectively. Thus the two isomers are present in both plasma and urine and their urinary excretions reflect directly their plasma levels.
mesh_terms: D002851:Chromatography, High Pressure Liquid; D004298:Dopamine / Q000031:analogs & derivatives* / Q000032:analysis / Q000097:blood / Q000652:urine; D006801:Humans; D007536:Isomerism; D007700:Kinetics; D013050:Spectrometry, Fluorescence
chemical_list: C022807:dopamine 4-O-sulfate; C007558:dopamine 3-O-sulfate; D004298:Dopamine