Electrochemical Determination of Vanillin in Commercial Food Products Using Cyclic and Differential Pulse Voltammetry at an Iodine-Coated Platinum Electrode

A voltammetric method for the determination of vanillin in food products utilizing iodine-coated polycrystalline platinum electrode is developed. Differential-pulse voltammetry (DPV) was applied for the quantitative determination of vanillin. A 0.1 M KCl solution was used as a supporting electrolyte. The measurements were made in the potential range –0.2 to 1.0 V vs. Ag/AgCl/[Cl–] = 0.1 M and all the reported potentials are referenced to this electrode. The anodic peak for the oxidation of vanillin was observed at ~0.84 V. The calibration curve was constructed for the peak current vs. the vanillin. A linear relationship between the peak current and the vanillin concentration was demonstrated with a calibration equation: ip(μA) = 0.003CVanillin + 0.1237. The working range for the developed method is for 1 to 250 µM and the coefficient of determination R2 is 0.9974. The limit of detection, LOD (based on S/N = 3) is 0.364 µM and the limit of quantitation (based on S/N = 10) is 1.21 µM. The developed method was successfully applied to the analysis of vanillin in food product samples like biscuits, cakes, and wafers with recovery values ranged from 94.41 and 103.18%.