Voltammetric sensors based on the mixed metal oxide nanoparticles for food dyes determination

Synthetic dyes of various classes are widely applied in food production due to the bright and reproducible colors, high stability, and improvement of the foodstuff appearance. The dye content in food is strictly regulated due to a wide range of possible negative health effects. Thus, reliable and simple methods are in demand for food quality control. The presence of electroactive fragments in the structure of synthetic dyes makes possible development of voltammetric sensors for their quantification. In current work, Sunset Yellow FCF, Brilliant Blue FCF, and Quinoline Yellow have been studied as analytes. Novel sensitive and selective voltammetric sensors based on glassy carbon electrodes modified with mixtures of metal oxide nanoparticles dispersed in water or surfactant media have been developed for the first time. Mixtures of cerium and tin dioxide nanoparticles dispersed in cationic hexadecylpyridium bromide or non-ionic Brij® 35 surfactants have been shown to be the best sensing layers for the determination of Sunset Yellow FCF and Quinoline Yellow, respectively. Voltammetric sensor based on the mixture of cerium dioxide and iron(III) oxide nanoparticles dispersed in water allows determination of Brilliant Blue FCF. Sensors are characterized by scanning electron microscopy, electrochemical impedance spectroscopy and voltammetry. A significant increase in the electroactive surface area and electron transfer rate has been confirmed. Differential pulse voltammetry in Britton-Robinson buffer has been applied for dye quantification. The analytical parameters achieved are improved vs. existing ones and sufficient for application to real samples. The sensors developed have been successfully tested in beverage analysis. The results obtained have been compared to data of the independent methods.