Ultrasensitive electrochemiluminescence biosensor for dopamine based on ZnSe, graphene oxide@multi walled carbon nanotube and Ru(bpy)32+

A ultrasensitive electrochemiluminescence (ECL) biosensor was designed for the detection of dopamine using ZnSe quantum dots and Ru(bpy)32+ as the signal probes, and graphite oxide and multi-walled carbon nanotube as the supporting matrix. The biosensor exhibits efficient and stable anodic ECL signal (at 1.10 V vs. Ag/AgCl) in phosphate buffer solution (pH 9.0) containing Tripropyl amine. The ECL emission decreases with adding dopamine, which can be attributed to the quenching effect from interaction between ZnSe and dopamine. The possible reaction mechanism of the ECL system is studied, and a method for the determination of dopamine is proposed. Under the optimal experimental conditions, the ECL emission decreases linearly with the logarithm of dopamine concentration in a wide linear range from1 × 10−9 to 1 × 10-5 mol L−1 with a detection limit of 6 × 10-10 mol L-1 (S/N = 3). The biosensor is also successfully applied to detect dopamine in human blood serum samples.