Voltammetric Determination of Vanillin Using a Pretreated Pencil Graphite Electrode

Abstract

In this study, a sensitive voltammetric method
 for the determination of vanillin in commercial food products was proposed
 using a pencil lead as an electrode material. In the cyclic voltammograms of
 vanillin recorded in pH 8.0 Britton Robinson buffer at the pre-oxidized pencil graphite
 electrode (p-PGE), a sharp peak was observed at about 520 mV (vs. Ag / AgCl
 electrode) attributed to the oxidation of vanillin. Subsequently, the
 voltammetric determination of vanillin based on its oxidation at p-PGE was
 carried out using the differential pulse voltammetry (DPV) technique under
 optimized conditions. DPV results showed that the oxidation peak current of
 vanillin increased linearly in the concentration range of 0.5 to 10.0 µM
 vanillin with a detection limit of 0.16 µM (based on 3Sb). In the final
 step, this voltammetric method was applied to the determination of vanillin in
 vanilla syrup samples. Results were in good agreement with the values indicated
 on the labels of samples.