Capillary electrophoresis with inhibited electrochemiluminescent detection for the trace analysis of epinephrine and dopamine

In this paper, a novel electrochemiluminescent (ECL) detection approach was developed for highly sensitive detection of ECL inhibitors based on the ECL inhibition of Ru(bpy)32+/2-(Dibutylamino)ethanol (DBAE) system. A microfluidic ECL detection cell was fabricated to couple with the capillary electrophoresis system, the electrochemical system and the postcolumn injection system. Both Ru(bpy)32+ and DBAE solutions were injected directly to the working electrode surface by a micro-infusion system to obtain a high and stable ECL signal. The performance of this setup was demonstrated by the analysis of two typical ECL inhibitors, dopamine and epinephrine. Under the optimal conditions, the limit of detection (LOD) for dopamine and epinephrine was 50nM and 5nM respectively. The proposed method was also successfully used for the trace analysis of dopamine and epinephrine in human serum samples.