Amperometric Bienzymic Sensor for Aspartame

An amperometric enzyme electrode for the determination of aspartame was developed by covalent immobilization of alcohol oxidase and α-chymotrypsin. A platinum based hydrogen peroxide electrode was used as the detector. Excellent sensitivity was obtained using batch, flow-through and flow injection methods with detection limits of 2 × 10 - 7 , 4 × 10 - 7 and 10 - 6 mol l - 1 , respectively. Different strategies for eliminating interfering compounds, including the introduction of an additional alcohol oxidase–catalase membrane and signal subtraction using an alcohol electrode, were employed. A recovery study on seven food samples was carried out and the results were satisfactory.