Response Surface Modeling of Electrochemical Data for Sensitive Determination of Sudan III in Food Products at the Surface of a Nanocomposite Modified Electrode

Abstract

In this work, application of a sensitive electrochemical technique assistedwithmultivariate optimizationmethods is presented for detection of Sudan III in food samples. At first, the synthesis and characterization of zinc oxide nanoparticles (ZnONPs) are described. The precipitation method is used for synthesis of ZnONPs with average particle sizes ranging from 20 to 30 nm. The structural analysis of the samples is performed usingXRD. Also, themorphology and particle sizes of the ZnONPs are confirmed by SEM. Next, the nanoparticles are used for modification of a carbon paste electrode (CPE) surface. The modified electrode is used for investigation of electrochemical behavior of Sudan III. Electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV) techniques are applied for characterization of the nanostructure modified electrode. For achieving the best response for Sudan III, effective experimental factors on the voltammetric determination of the analyte are optimized by rotatable central composite design (RCCD) and response surface methodology (RSM). The nanostructured modified electrode shows an excellent electrocatalytic property on the oxidation peak current of Sudan III. The electrochemical behavior of Sudan III at the surface of zinc oxide nanoparticles modified carbon paste electrode (ZnONPs/CPE) are investigated by differential pulse voltammetry (DPV), cyclic voltammetry (CV), and chronocoulometry. Analytical parameters such as linearity, selectivity, repeatability, and stability are also investigated. At the optimized conditions, the linear dynamic ranges for Sudan III are obtained 0.05–1.0 and 1.0–15.0μM and the detection limit is achieved 2.56 nM. Also, the proposed sensor is successfully applied for detection of Sudan III in real complicated samples.