An Ultrasensitive Electrochemical Sensor Pd/MWCNTs-N-S for Detection of Dopamine

Dopamine (DA) is an important catecholamine neurotransmitter in human metabolism that is associated with various critical diseases. Accurate detection of DA is of great significance for the diagnosis of these diseases. Here, we constructed a sensitive electrochemical sensor, S, N co-doped multi-walled carbon nanotubes (MWCNTs-N-S) loaded with Pd nanoparticles (Pd/MWCNTs-N-S). The linear range of the Pd/MWCNTs-N-S sensor is from 0.0001 to 2.0 mM, and the limit of detection (LOD) is 4.37 nM (S/N = 3) for DA detection. The improved detection performance of this sensor is attributed to the optimization of MWCNTs carrier structure and surface properties by N, S co-doping, as well as the significant improvement of electrochemical surface area (ECSA) for the commendable dispersion of Pd nanoparticles (3.79 nm). What is more, the Pd/MWCNTs-N-S sensor also exhibits good reproducibility, stability, and anti-interference ability. Overall, this study presents a straightforward strategy for the potential applications of Pd-based double co-doped MWCNTs sensors.