Separation of serotonin from catechols by capillary zone electrophoresis with electrochemical detection

Capillary zone electrophoresis with electrochemical detection is demonstrated with columns having only 9-microns inner diameter. Amperometric detection limits of 0.7 amol are reported for serotonin. The difficult problem of resolving serotonin and dopamine--two neurotransmitters of interest having similar electrophoretic mobilities--is addressed by chemical means to improve selectivity. These include buffer modification with 2-propanol and a system employing borate complexation of the catechol in combination with sodium dodecyl sulfate micelles.