Carbon-Paste Electrode Modified by ß-Cyclodextrin as Sensor for Determination of Sunset Yellow FCF and Ponceau 4R in Soft Drinks

One of the disadvantages of voltammetric analysis is the significant amount of sample required for electrolysis in the cell. In this paper a methodology close to adsorption stripping voltammetry was proposed to solve this problem at an analysis of two azo dyes - Sunset Yellow FCF and Ponceau 4R. As a working electrode, a carbon-paste electrode modified with ss-cyclodextrin, a cyclic oligosaccharide that can form supramolecular complexes with azo dyes was proposed. The redox behavior of Sunset Yellow FCF and Ponceau 4R, the number of electrons, protons, and charge transfer coefficients onto the proposed sensor have been studied. Using square-wave voltammetry, the conditions for the determination of two dyes were optimized. Under the optimal conditions the calibration plots are linear in the ranges 71-565 mu g/L and 189-3024 mu g/L for Sunset Yellow FCF and Ponceau 4R, respectively. Finaly, the new sensor has been tested for square-wave voltammetric determination of Sunset Yellow FCF and Ponceau 4R in soft drinks, and RSD values (max. 7.8 and 8.1%) indicated satisfactory precision for both analyzed samples.