An Amperometric Sensor Based on Tin Dioxide and Cetylpyridinium Bromide Nanoparticles for the Determination of Vanillin

Abstract

Voltammetric characteristics of vanillin are determined using electrodes modified with tin dioxide nanoparticles dispersed in surfactants of various nature in the Britton–Robinson buffer solution. The best characteristics are observed for a glassy carbon electrode modified by a dispersion of SnO₂ nanoparticles in cationic cetylpyridinium bromide (SnO₂–CPB/GCE). The electrode is characterized by cyclic voltammetry and electrochemical impedance spectroscopy. A fourfold increase in the effective surface area of SnO₂–CPB/GCE and a significant decrease in charge transfer resistance are shown in comparison with a GCE. The electrooxidation of vanillin proceeds irreversibly with the participation of two electrons and two protons and is controlled by the diffusion of the analyte. A sensor based on a SnO₂–CPB/GCE was developed to determine vanillin; it functions under conditions of differential pulse voltammetry. The analytical ranges for vanillin are 0.10–100 and 100–500 µM with the limits of detection and quantification 20 and 67 nM, respectively. The developed sensor is selective to vanillin in the presence of inorganic ions, saccharides, ascorbic acid, and a number of phenolic compounds. The sensor is used for the determination of vanillin in perfumes for household chemicals and vanilla essential oils. The results are in good agreement with the data of gas chromatography.