Voltammetric Determination of Vanillin Using a Pretreated Pencil Graphite Electrode

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