Construction of an electrochemical platform with carbon nanotubes and aluminium doped zinc oxide nanoparticles for the sensitive determination of sunset yellow

Sunset yellow, a synthetic colorant and used to improve the texture and the appearance of food samples, can adversely affect humans. The development of a sensitive method to analyse food products for the accurate determination of sunset yellow is of importance for the level of risk to human health and thus food safety. The present study aimed to prepare a voltammetric method for the precise detection of sunset yellow content in a commonly consumed powdered beverage and pharmaceutical products. For this purpose, a sensitive method utilizing a voltammetric platform was constructed by modifying a glassy carbon electrode (GCE) with carbon nanotubes (MWCNTs) and aluminium doped zinc oxide (AZO). Cyclic voltammetry (CV) and electrochemical impedance spectroscopic (EIS) measurements indicated that the proposed voltammetric platform (GCE/MWCNTs/AZO) possessed high electro-active surface area and lower value of charge transfer resistance (Rct) and therefore, could serve as a promising sensing material. The GCE/MWCNTs/AZO system improved voltammetric behaviour of sunset yellow at an accumulation time of 210 s and indicated good electrocatalytic activity due to high synergistic effect between MWCNTs and AZO nanoparticles. This method of analysis exhibited a dynamic working range from 4.0×10⁻⁹ to 7.5×10⁻⁶ M with a limit of detection (LOD) of 9.5×10⁻¹⁰ M for sunset yellow. The GCE/MWCNTs/AZO system was successfully utilized for the electroanalysis of beverages and pharmaceuticals for detection of sunset yellow. Voltammetric measurements indicate that the GCE/MWCNTs/AZO system enables good accuracy and high precision for the determination of sunset yellow.