Electrochemical Study of Tartrazine Using a Carbon Paste Electrode Modified with Nanostructured Materials
Authors: Rivera-Hernández Selene Irisais , Roque-de la O Noemi , Vázquez-Huerta Gerardo , Corona-Avendaño Silvia , Palomar-Pardavé Manuel , Romero-Romo Mario Alberto 
Published: February 2020

Tartrazine (Trz) is one of the most widely used azoic dyes in the alimentary industry; it is added to a great variety of products, for this reason it is necessary to develop analytic methods and materials which allow its detection and quantification. For this purpose ultraviolet-visible spectrophotometry (UV-Vis), high performance liquid chromatography (HPLC), capillary electrophoresis and potentiometric and voltammetric sensors have been used. Potentiometric and voltammetric sensors have many advantages such as simplicity; rapid analysis and cost, besides most recently developed sensors are environmentally friendly and avoid the use of mercury which is toxic. In this regard, carbonaceous electrodes such as carbon paste electrodes have been employed due to its low cost, they are easy to manufacture and can be modified with a great diversity of materials an methods. Nanostructured materials such as bamboo-shaped multiwalled carbon nanotubes (BS-MWCNT) and Pt nanoparticles (Pt/NPs) allow great electrochemical activity and in this work are proposed to modify a CPE in order to detect and quantify Tartrazine samples. The electrochemical experiments were performed in a potentiostat/galvanostat AUTOLAB30, using NOVA 2.1 software, a typical three-electrode electrochemical cell was used. A Pt wire was employed as counter electrode; Ag/AgCl (3M NaCl) in a Luggin capillary as reference electrode, the working electrode was a CPE prepared by mixing graphite powder and mineral oil in a proportion 1:1, the CPE was modified by adding an aliquot of 5mL of BS-MWCNT dispersion and by adding an aliquot of 5mL of Pt/NPs and BS-MWCNT. Cyclic voltammograms obtained in 0.5M NaCl + 2.0x10-5 M Trz (adjusted to a pH=4.0) are shown in Figure 1. In the case of CPE, a peak due to Trz oxidation appears at 0.77V, the oxidation peak is positively shifted (0.15V) when BS-MWCNT are added and now appears at 0.92V, even though the oxidation potential is greater on BS-MWCNT the associated current is also greater. When the experiment is performed on BS-MWCNT + Pt/NPs the oxidation peak appears at 0.99V, the associated current in this last case is greater than in the previous cases, a great current leads to an improvement of some analytical parameters such as sensibility, which may help to detect and quantify Trz more accurately.

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Figure 1