Electrochemical fabrication of a novel ZnO/cysteic acid nanocomposite modified electrode and its application to simultaneous determination of sunset yellow and tartrazine

•A glassy carbon electrode was modified with a new nanocomposite.•ZnO nanofilms were deposited on cysteic acid polymer framework.•The nanostructure deposit enhanced the current responses of food additives.•Sensitive and selective determination of sunset yellow and tartrazine was performed.•The method is applicable to routine analysis of these dyes in soft drinks.

A new nanocomposite (ZnO/Cysteic acid) was deposited on glassy carbon electrode by cyclic voltammetry. Uniform deposition of the nanocomposite was observed by scanning electron microscopy. The electron transfer characteristics of two food additives, sunset yellow and tartrazine, were greatly improved on the modified electrode. The prepared electrode was used in the sensitive simultaneous determination of sunset yellow and tartrazine by differential pulse voltammetry. Linear calibration curves were obtained in the concentration ranges of 0.1-3.0, and 0.07-1.86 μM, and detection limits of 0.03 and 0.01 μM for sunset yellow and tartrazine, respectively. The proposed method was evaluated by determination of the dyes in processed soft drinks with satisfactory results (recovery > 95% and RSD% < 5%).