A simple, sensitive and reliable electrochemical sensor was developed for detection of melamine based on gold nanoparticles deposited on a graphene doped carbon paste electrode. The sensor was characterized using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and scanning electron microscopy (SEM). Melamine sensing is based on the interaction between melamine molecules and the gold nanoparticles causing suppression in the peak current. The decrease in the value of the current and the concentration of melamine showed a good linear relationship in the concentration range of 2.0 × 10−10 to 8.0 × 10−7 M and 8.0 × 10−7 to 8.0 × 10−3 M with the limit of detection (LOD) of 1.8 × 10−11 M. The proposed method was successfully applied in the quantitative determination of melamine in spiked milk and milk powder with RSDs of 0.09–3.16% and recoveries of 95.00–101.75%.
