Poly (Diethylcarbamazine) electropolymerized carbon paste electrode: A simple and reliable sensor for vanillin quantification in food products

This study introduces a new poly (diethylcarbamazine citrate)-modified carbon paste electrode (poly-DEC/MCPE) electrochemical sensor for the rapid and sensitive detection of vanillin (VLN), an aromatic phenolic compound used in food and pharmaceuticals. The sensor was fabricated via in situ electropolymerisation of diethylcarbamazine (DEC) on a carbon paste electrode using cyclic voltammetry (CV). Potassium ferrocyanide measurements revealed an improved electroactive surface area and faster electron-transfer rates than those of the bare carbon paste electrode (BCPE). The sensor performance was systematically evaluated across various pH levels, scan rates, and VLN concentrations, revealing an adsorption-controlled oxidation mechanism. Poly-DEC/MCPE exhibited electrocatalytic activity in the oxidation of VLN, with a detection limit of 0.072 µM and a quantification limit of 0.24 µM. Interference studies confirmed the selectivity of the sensor, with less than 5% signal deviation among common inorganic and organic species. When applied to real food samples, such as vanilla flavoured cakes, it showed high recovery rates (99.4–101.6%), validating its practical usefulness. The proposed poly-DEC/MCPE offers a low-cost, reproducible, and portable alternative to conventional methods for routine food quality control and pharmaceutical analyses.