Evaluation of an Electrochemical Sensor Based on Gold Nanoparticles Supported on Carbon Nanofibers for Detection of Tartrazine Dye

An electrochemical sensor for the detection of tartrazine (Tz), a synthetic azo dye customarily found in commercial soft drinks, is herein reported. This sensor is based on a carbon paste electrode (CPE) with gold nanoparticles (AuNP) anchored in carbon nanofibers (CNF). The CNF/AuNP nanocomposite was characterized by scanning electron microscopy (SEM), energy dispersive X-Ray spectroscopy (EDS), X-ray diffraction (XRD), and electrochemical impedance spectroscopy (EIS). The electrochemical evaluation and detection of Tz was carried out by using differential pulse voltammetry (DPV) and cyclic voltammetry (CV). In terms of sensibility, the CNF/AuNP-CPE electrochemical sensor exhibits a linear range of 3.29 – 49.50 µmol L−1 with a coefficient of determination r2 of 0.9946, a limit of detection (LOD) of 0.8 ± 0.07 µmol L−1, and a limit of quantification (LOQ) of 2.64 ± 0.23 µmol L−1. Furthermore, the proposed sensor exhibits excellent selectivity toward Tz in the presence of the sunset yellow dye, and other interferents such as sodium benzoate, NaNO3, NaHCO3, glucose and citric acid. In addition, a DFT computational study suggests that noncovalent interactions contribute to the stabilization of the Tz-AuNP assemblies at the electrode/electrolyte interface. The optimal reproducibility, repeatability, and stability during the Tz detection in commercial soft drinks makes CNF/AuNP-CPE an appealing electrode for analytical purposes.