Determination of octopamine in human plasma by capillary electrophoresis with optical fiber light-emitting diode-induced fluorescence detection

A new analytical method based on capillary electrophoresis (CE) separation and optical fiber light-emitting diode (LED)-induced fluorescence detection has been developed for the determination of octopamine. Naphthalene-2,3-dicarboxaldehyde (NDA) was used for precolumn derivatization of octopamine. The separation and determination of the derivative was performed using a laboratory-built CE system with an optical fiber LED-induced fluorescence detector. Optimal separation was obtained at 20 kV using a background electrolyte solution consisting of 25 mM sodium borate (pH 9.2). High sensitivity detection was achieved by the optical fiber LED-induced fluorescence detection using a purple LED as the excitation source. The limit of detection (signal/noise=3) for octopamine was 5.0 x 10(-9)M. A calibration curve ranging from 1.0 x 10(-8) to 5.0 x 10(-7)M was shown to be linear. Using this method, the levels of octopamine in human plasma from healthy donors were determined.