Electrochemical detection of dopamine in the presence of ascorbic acid using PVP/graphene modified electrodes.

Graphene (GR) was synthesized through electrochemical reduction of graphene oxide and characterized by spectroscopic and electrochemical techniques. Polyvinylpyrrolidone (PVP)/graphene modified glassy carbon electrode (PVP/GR/GCE) was prepared and applied for the fabrication of dopamine (DA) sensors without the interference of ascorbic acid (AA). Compared to bare GCE, an increase of current signal was observed, demonstrating that PVP/GR/GCE exhibited favorable electron transfer kinetics and electrocatalytic activity towards the oxidation of dopamine. Furthermore, PVP/GR/GCE exhibited good ability to suppress the background current from large excess ascorbic acid. Amperometric response results show that the PVP based sensor displayed a wide linear range of 5×10(-10) to 1.13×10(-3) mol/L DA with a correlation coefficient of 0.9990 and a detection limit of 0.2 nM (S/N=3). The determination of dopamine in urine and human serum samples were studied.