A sensitive and selective electrochemical sensor based on N, P-Doped molybdenum Carbide@Carbon/Prussian blue/graphite...

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.