Capillary electrophoresis-laser-induced fluorescence detection of rat brain catecholamines with microwave-assisted derivatization

Abstract

In this study, a rapid and sensitive method is described for the catecholamines detection in rat brain. CE with LIF detection for the determination of FITC derivatized catecholamines (dopamine, epinephrine, and norepinephrine) was demonstrated. Conventional water bath and microwave-assisted derivatization methods were employed and a significant reduction in the derivatization time from 2 h for the conventional water bath at room temperature (ca. 25°C) to 2 min for the microwave-assisted derivatization was achieved. Online sample concentration of field-amplified sample stacking (FASS) method was employed to achieve higher sensitivities (the detection limits obtained in the normal injection mode ranged from 2.6 to 4.5 ng L⁻¹ and in the FASS mode ranged from 22 to 34 pg L⁻¹). Furthermore, this microwave-assisted derivatization CE-LIF method successfully determined catecholamines in rat brain with as low as 100 ng L⁻¹ (FASS mode) to 10 μg L⁻¹ (normal injection mode). This CE-LIF method provided better detection ability when compared to the best reports on catecholamines analyses.