Validity of liquid chromatography with electrochemical detection for measuring dopamine in human plasma

We tested the validity of liquid chromatography with electrochemical detection (LCEC) for measuring dopamine levels in human plasma, by adding known amounts of dopamine standard to human plasma, and by comparison with levels obtained using the catechol-O-methyltransferase radioenzymatic (COMT-RE) assay technique. The correlation between the obtained dopamine concentrations and picograms of added standard was 1.00 and the correlation between the two assay techniques across 32 plasma samples was 0.97. These results demonstrate that LCEC validly measures human plasma dopamine.