Quantification of noradrenaline and dopamine in Portulaca oleracea L. by capillary electrophoresis with laser-induced fluorescence detection

In this paper, a rapid and sensitive method is described for the quantification of noradrenaline (NA) and dopamine (DA) in Portulaca oleracea L. After derivatization in a dark ultrasonic bath for 4 h, fluorescein isothiocyanate (FITC) derivatives of NA and DA were separated by capillary zone electrophoresis (CZE) in 5.5 min and detected with laser-induced fluorescence. In the concentration range (0.05-2.00 muM), the calibration curves reveal linear relationships between the peak-area for each analyte and its concentration (correlation coefficients: 0.9970 for NA and 0.9998 for DA). The recoveries are in the range of 94.6-97.3%. The detection limits for NA and DA are 1.02 and 0.34 nM, respectively. (C) 2002 Elsevier Science B.V. All rights reserved.