Highly sensitive amperometric food sensor for Sudan-I dye using nanocomposites modified working electrode

Abstract

Sudan-I dye (1-phenyl azo-2-naphthol) is commonly used as a coloring agent in the food and textile industries. The excessive use of Sudan-I dye has ill effects on human health. A sensitive and selective electrochemical detection is required for sensing Sudan-I dye in food products. An electrochemical sensor based on a modified working electrode using ternary mixed metal oxide (Ti/Fe/CuO) nanocomposites was developed for sensing Sudan-I dye. Using a modified Sol-gel technique, Ti/Fe/CuO mixed metal nanocomposites were synthesized. FT-IR, UV–Visible, SEM, and XRD techniques were used to characterize the Ti/Fe/CuO nanocomposites. Different voltammetric techniques, such as Cyclic voltammetry (CV), Differential Pulse Voltammetry (DPV), and Linear Sweep Voltammetric (LSV) were used for qualitative and quantitative estimation of Sudan-I dye. Electrochemical Impedance Spectroscopy (EIS) was used for structural information of interface. The specially designed working electrode acted as a sensor and shows good sensing ability toward Sudan-I dye in real food samples. A linear range of 0–160 µM and 0–200 µM for red chili sauce and powder (real samples), respectively was observed. Under the optimized condition, the current response was linear with a detection limit of 0.02 µM/L. A characteristic oxidation peak of 7263.36 µA at 0.2606 V and a reductive peak of − 1465 μA at − 0.3714 V are the characteristic peaks for Sudan-I dye. The effect of change in pH, scan rate, storage, stability behavior, and concentration of Sudan-I dye was evaluated. A comparative study was done between glassy carbon electrodes, bare Copper metal, and ternary metal oxide NCs modified electrodes. The developed electrochemical sensor demonstrated reliability, reproducibility, stability, speed, and non-specificity, making it suitable for both quantitative and qualitative analysis of food additives, preservatives, coloring agents, and flavoring agents.