Differential pulse voltammetry detection of sunset yellow and tartrazine in beverages using rGO-BaMoO₄ composite

Reduced graphene oxide (rGO) and spherical barium molybdate (BaMoO₄) crystal were prepared using hydrothermal method, respectively. The rGO-BaMoO₄ composite was then formed by sonication mixing. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) were applied to characterize the microstructure of rGO-BaMoO₄ composite. Moreover, cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and differential pulse voltammetry (DPV) techniques were utilized to investigate its electrochemical performance. Due to the synergistic effect of the two materials, the rGO-BaMoO₄ composite modified glassy carbon electrode (rGO-BaMoO₄/GCE) exhibits superior electroanalytical performance toward sunset yellow (SY) and tartrazine (TZ) assay, including wide linear range from 0.1 to 1.0 µmol/L and 1.0 to 80 µmol/L, low detection limits of 0.070 (for SY) and 0.078 µmol/L (for TZ), excellent selectivity, good reproducibility, and high stability. What is more, the constructed rGO-BaMoO₄/GCE was applied for the assay of SY and TZ in commercial beverage samples. The satisfactory recoveries of 97-108% obtained in real samples reveal the potential of rGO-BaMoO₄/GCE in practical applications.