A Sensitive and Selective Electrochemical Sensor Based on N, P-Doped Molybdenum Carbide@Carbon/Prussian Blue/Graphite Felt Composite Electrode for the Detection of Dopamine

Abstract In this paper, a composite electrode of N,P-doped Mo2C@C/Prussian blue (PB)/graphite felt (N,P-Mo2C@C/PB/GF) was prepared by a simple method and used for sensitive and effective detection of dopamine (DA). N,P-doped Mo2C nanospheres were prepared by using phosphomolybdic acid (PMo12) as an initiator to promote the polymerization of polypyrrole. Such nanospheres were used to accelerate the deposition process of PB from K3[Fe(CN)6] and FeCl3 in solution. The N,P-Mo2C@C/PB nanohybrid was then anchored to GF in order to obtain the electrochemical sensor. Two linear ranges were extrapolated for dopamine detection: from 0.18 to 30 μmol·L-1 with a sensitivity of 0.268 μA·μmol-1, and from 30 to 280 μmol·L-1 with a sensitivity of 0.045 μA·μmol-1. The device showed a detection limit as low as 0.011 μmol·L-1, an excellent selectivity to DA over common interfering analytes, and a favorable long-time stability. Finally, the sensor was used for quantitative analysis of DA in the 10-fold dilution of human serum (10%) and exhibited a satisfactory recovery.