Abstract

An electrochemical sensor based on nanostructured planar carbon electrodes (nanoSPCE) modified with a SiO₂ biocomposite film containing MnO₂ particles and enzymes glucose oxidase and invertase was developed. MnO₂ particles obtained by electrochemical deposition possessed electrocatalytic activity toward hydrogen peroxide. Glucose oxidase (GOx) and invertase (Inv) were encapsulated into SiO2 film by method of electroassisted deposition. The electrode modified with biocomposite film nanoSPCE/MnO₂/GoX/Inv/SiO₂ was electroactive toward sucrose. The indicator reaction was oxidation of H₂O₂ – the product of bienzymatic reaction which was catalyzed by MnO2 on the electrode surface. The linearity range of the calibration graph for the voltametric determination of sucrose using developed modified electrode is 0.017-0.342 mg/ml, the detection limit is 0.006 mg/ml. The obtained nanoSPCE/MnO₂/GoX/Inv/SiO₂ electrode demonstrated satisfactory stability of the analytical signal during one month of operation. The developed method was used for sucrose determination in the honey samples. The 50-fold molar excess of glucose and fructose does not interfere the determination of sucrose.

Keywords: screen printed nanostructured carbon electrode, manganese dioxide, glucose oxidase, invertase, hydrogen peroxide, sucrose, electrochemical sensor, biosensor, cyclic voltammetry, SiO₂ film

Article language: Ukr