N-Doped carbon nanorods as ultrasensitive electrochemical sensors for the determination of dopamine

Nitrogen-doped carbon nanorods (N-CNRs) are prepared by a direct carbonization method using polyaniline nanorods as the carbon precursor. The electrochemical behavior of the N-CNRs-Nafion modified electrode is evaluated in connection with dopamine and ascorbic acid by cyclic voltammetry and differential pulse voltammetry. Experimental results indicate that the N-CNRs modified electrode has improved current response and fast electron transfer kinetics. The linear response for the selective determination of dopamine in the presence of ascorbic acid is obtained in the range of 0.008 μM to 15.0 μM with a detection limit of 8.9 × 10−9 M (S/N = 3) by differential pulse voltammetry under optimum conditions. The N-CNRs-Nafion modified electrode exhibits a wide linear range, very low detection limit and anti-interference ability. Meanwhile, a kinetic reaction process and a reaction mechanism for the N-CNRs are also proposed.