Polyoxometalates-graphene nanocomposites modified electrode for electro-sensing detection of Sudan I in food

Sudan I, a lipophilic azo dye -dye, is desirable and urgent to be accurate detected due to its increasing levels and high toxicity in food and environmental monitoring and analysis. Herein, a sensitive electrochemical sensor for Sudan I was established based on a new K₁₀P₂W₁₈Fe₄(H₂O)₂O₆₈ functionalized carbon nanomaterials (Fe₄P₂W₁₈-GNPS). The electrode modified nanocomposite, Fe₄P₂W₁₈-GNPS, was successfully fabricated and characterized by FTIR, SEM and UV-vis. The effective combination of Fe₄P₂W₁₈ and graphene exhibited high electrocatalytic activity towards the oxidation of Sudan I, promote charge transfer, and more sensing sites. Under optimized experimental conditions, the proposed differential pulse voltammetry (DPV) showed excellent analytical performances for Sudan I with the limit of detection (LOD) of 5 nM (S/N = 3), the sensitivity of 13.10 μA·μM^-1cm^-2 at the 0.005-2 μM and 0.39 μA·μM^-1cm^-2 at 10-200 μM. The stability and reproducibility make the electrochemical sensor suitable for detecting the Sudan I in food.