Kinetic approach in the development of a gold nanoparticle based voltammetric sensor for Sudan I

•Gold nanoparticle based sensor for the determination of Sudan I was developed.•Kinetic parameters were evaluated.•Application studies were carried out.

This paper describes the development of an electrochemical sensor based on the catalytic activity of gold nanoparticles deposited on a glassy carbon electrode (AuNP/GCE) for the determination of Sudan I in food samples. The electrocatalytic activity of AuNPs towards the oxidation of Sudan 1 was studied by cyclic voltammetry and square wave voltammetry (SWV). The cyclic voltammogram of the modified electrode has a pair of well-defined quasi-reversible redox peaks with a formal potential of 0.295 V (vs. Ag/AgCl) at a scan rate of 0.1 Vs−1. The sensor exhibited two distinct linear response ranges of 4.0 × 10−5 - 1.0 × 10−3 M and 2.0 × 10−5 - 7.0 × 10−7 M. The lower detection limit of the sensor was 1.0 × 10−8 M. The kinetic parameters such as the number of electrons, the electron transfer coefficient (α) and the standard rate constant of electron transfer (ks) was evaluated to be 1.0, 0.48 and 1.5 × 10−1 s−1 respectively. The average surface concentration of Sudan 1 on the surface of AuNP/GCE was calculated to be 1.2 × 10−9 mol cm−2. The proposed sensor has been successfully used to determine Sudan I in food products such as ketchup and chilly sauce.