Fabrication of nano Fe₃O₄-reduced graphene oxide composite modified glassy carbon electrode and its application for the determination of dopamine

The nano Fe₃O₄-reduced graphene oxide composite modified glassy carbon (Fe₃O₄-rGO/GC) electrode was fabricated by electrochemical reduction method, and used for the determination of dopamine (DA).The nano Fe₃O₄-rGO composites were characterized by SEM, TEM and cyclic voltammetry. The electrochemical behavior of DA was investigated in pH=7.0 phosphate buffer saline (PBS) by cyclic voltammetry. Compared with bare GC electrode and rGO-modified (rGO/GC) electrode, the electrochemical active area and the oxide peak current i_pa of Fe₃O₄-rGO/GC electrode increase significantly, owing to the synergistic action between nano Fe₃O₄ and rGO. The oxide peak current i_pa shows good linear relationship with the concentration of DA in the range of 6×10^-8-2×10^-6 mol/L and 2×10^-6-8×10^-5 mol/L. The detection limit is 4.0×10^-9 mol/L (signal-noise ratio S/N=3).The determination of DA hardly interfere with the coexistence of ascorbic acid and uric acid. The proposed method is further applied to the determination of DA in DA injections with satisfied results, and the recovery of DA is 97.1%-103.9%.