Capillary zone electrophoresis hyphenated with laser-induced fluorescence detection for sensitive determination of noradrenaline and dopamine with 5-(4, 6-dichloro-s-triazin-2-ylamino) fluorescein as fluorescent label

A new capillary zone electrophoresis method with laser-induced fluorescence detection is presented for the determination of noradrenaline (NA) and dopamine (DA). The fluorescent reagent, 5-(4,6-dichloro-s-triazin-2-ylamino) fluorescein, which readily reacts with amine group under mild conditions, was initially used to label the two compounds. Under optimized separation and labeling conditions, linear relationship between peak area and analyte concentration was obtained with high sensitivity (nM level). The applicability of the method for complex sample analysis was validated by determining the two compounds in a human serum and an herb, Portulaca oleracea L with recoveries ranging from 89% to 102%.