Electrochemical detection of Allura red azo dye using nitrogen-doped reduced graphene oxide based electrochemical sensor

Cardenas-Riojas A.A.; Ascencio-Flores Y.F.; Solis-Yancan D.S.; Palm R.; Nerut J.; Jäger R.; Möller P.; Volobujeva O.; Merisalu M.; La Rosa-Toro A.; Baena-Moncada A.M. · Microchemical Journal (2025) · DOI: 10.1016/j.microc.2025.116052

Resumen

This work focuses on developing an electrochemical sensor based on a carbon paste electrode (CPE) modified with reduced graphene oxide doped with nitrogen (rGO[sbnd]N) and graphite (G), resulting in the rGO-N-G/CPE sensor. This sensor is designed for the detection of Allura Red (AR) food coloring in soft drinks in Peru. HR-SEM, SEM-EDX, and HR-TEM were used for morphological and element analysis of rGO[sbnd]N. The atomic and structural composition were analyzed using time-of-flight secondary ion mass spectrometry, IR, and Raman spectroscopy. The rGO-N-G/CPE sensor was characterized by electrochemical techniques such as electrochemical impedance spectroscopy and cyclic voltammetry. The detection of AR was performed using square wave voltammetry, SWV, yielding the rGO-N-G/CPE sensor with a concentration range of 2.5–5.7 μmol L−1, and a low detection limit of 0.64 μmol L−1. Furthermore, the modified electrode exhibits excellent stability (%RSD: 0.63 %), repeatability, reproducibility (%RSD < 10 %), and selectivity in the presence of various interfering substances found in beverages, including sodium bicarbonate, glucose, sodium citrate, citric acid, and sodium nitrate. The sensor was also evaluated for the determination of AR content in three soft drink samples. Finally, the electrochemical analysis was validated using UV–visible spectrophotometry, demonstrating excellent correlation between the two methods. This validation highlights the potential of the electrochemical method as a simple, cost-effective, and rapid approach for AR detection.

Instituciones: Universidad Nacional de Ingeniería