An eco-friendly electrochemical approach for determination of sunset yellow at a Co3O4@biochar modified pencil graphite electrode

The quantitative detection of food additives containing sunset yellow is of great significance to food safety. In this study, a simple, low-cost, and sustainable pencil graphite electrode modified with Co3O4@biochar is proposed for the accurate detection of sunset yellow in beverages. Absorbent cotton is selected as the biological carbon source, which is immersed in cobalt salt and then pyrolyzed in air to achieve the preparation of nanocomposite Co3O4@biochar (Co3O4@BC-700). The successful synthesis of Co3O4@BC-700 is confirmed by XRD, SEM, TEM, XPS and BET. It is gratifying that the Co3O4@BC-700 modified pencil graphite electrode enables the electrochemical quantitative detection of sunset yellow with a linear range of 5.0 × 10−6–4.0 × 10−3 M, a detection limit as low as 1.3 × 10−6 M, and a cost as low as 0.5 Yuan per electrode. It also has excellent selectivity, stability and repeatability. This electrochemical sensor based on Co3O4@biochar can be employed for the concentration detection of sunset yellow in beverages. This work attempts to provide a novel path for the electrochemical detection of food additives.