Sensitively Simultaneous Determination of Sunset Yellow and Tartrazine in Foods Based on Polypyrrole Modified Oxidized Single-Walled Carbon Nanotubes

A highly sensitive method for simultaneous electrochemical determination of Sunset yellow (SY) and Tartrazine (Tz) in foods was proposed based on the stable aqueous dispersions of polypyrrole (ppy) decorated oxidized single-walled carbon nanotubes (SCNT-COOH). Under optimal experimental conditions, the dispersions modified glassy carbon electrode (GCE) exhibited remarkable sensitivity of (72.36 μA/μM and 23.39 μA/μM) with wide linear responses to Sunset yellow and Tartrazine ranging from 5.0 × 10−9 to 1.0 × 10−6 M and 7.0 × 10−9 to 1.0 × 10−6 M, and detection limits as low as 7.0 × 10−10 M and 1.0 × 10−9 M for Sunset yellow and Tartrazine, respectively, which might be due to hydrogen bonds between hydroxyl groups of dyes and oxygen-containing groups of the composite. In addition, the electrostatic interaction between the dyes and the ppy may also play a main role except for good dispersibility.