Simultaneous Electrochemical Quantification of Foodstuff Dyes Allura Red and Tartrazine Using a Bare Carbon Paste Electrode

Abstract

A bare carbon paste electrode, BCPE, was used to determine simultaneously the foodstuff dyes Allura Red (AR) and Tartrazine (Trz) in aqueous media, achieving the following analytical parameters: for AR sensitivity of (0.126 ± 0.002) μA (mg l)−1 with a limit of detection (LOD) of (0.14 ± 0.004) mg l−1 and a Trz sensitivity of (0.392 ± 0.024) μA (mg l)−1 with a LOD of (0.310 ± 0.034) mg l−1. Additionally, the individual and simultaneous quantifications of AR and Trz in real samples, were performed through the electrochemical method proposed in this work. In the case of individual dyes quantification, the results were like those found using UV–vis spectrophotometry, however, contrary to the electrochemical method proposed in this work, the spectrophotometric method cannot be used for the simultaneous quantifications due to the dyes absorbance overlap. Furthermore, the BCPE is a robust electrode that, contrary to other modified CPE reported for this purpose, can be reused for multiple quantifications by simple mechanical polishing of its electroactive surface, beside its excellent reproducibility, accuracy, and lifetime. Usually the dyes are found in concentrations of mg l−1 in foodstuffs, which makes this electrode suitable for use in foods and non-alcoholic beverages.