High-performance liquid chromatographic determination of dopamine sulfoconjugates in urine after l-DOPA administration

A procedure was developed for the separation and determination of dopamine-3-O-sulfate (DM-3-S) and dopamine-4-O-sulfate (DM-4-S) in the urine of subjects administered l-DOPA. The method consists of sample preparation using cation- and anion-exchange resins followed by determination of the sulfates by high-performance liquid chromatography. The addition recoveries were 96 ± 2.9% (S.D.) for DM-3-S and 93 ± 3.0% (S.D.) for DM-4-S. Twenty samples could be measured per day. When every 2-h urine specimen from normal subjects was analysed after l-DOPA administration (0.5 g), the maximum excretion of each sulfate was observed in the second 2-h specimen. For the first 6 h 7.5 ± 1.5% (S.D.) of the administered l-DOPA was excreted as DM-O-sulfates. During this time, the ratio of DM-4-S to the DM-O-sulfates was 11.7 ± 0.58% (S.D.).