RESUMO
MnMoO4/g-C3N4 nanocomposites were synthesized by a hydrothermal method.The MnMoO4/g-C3N4 nanocomposites were characterized by X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FT-IR)and transmission electron microscopy(SEM)to analyze their morphology and structure.The MnMoO4/g-C3N4 was coated on the surface of the glassy carbon electrode(GCE)by a drop coating method and thus a electrochemical sensor for detection of metronidazole(MNZ)was successfully constructed.The electrochemical properties of the MnMoO4/g-C3N4/GCE electrode were characterized by cyclic voltammetry(CV)and differential pulse voltammetry(DPV).The effects of pH value and scanning rate on the current response were investigated.Under optimal experimental conditions,this electrochemical sensor showed a wide linear detection range(0.5-2400 μmol/L)and a low limit of detection(LOD = 1.33 nmol/L,3σ/k)for detection of MNZ.Besides,this sensor showed excellent selectivity,stability and reproducibility.The sensor was used to detect MNZ residue in eggs and milk samples,with recoveries of 97.7%-103.7%and 96.9%-102.4%,and relative standard deviations of 1.1%-2.2%,respectively,indicating that the prepared MnMoO4/g-C3N4/GCE sensor could be successfully applied to detection of MNZ in food samples.