Non-enzymatic electrochemical sensing of glucose and hydrogen peroxide using a bis(acetylacetonato)oxovanadium(iv) complex modified gold electrode

Abstract

A non-enzymatic electrochemical sensor, bis(acetylacetonato)oxovanadium(IV) complex, [VO(acac)₂], fabricated on a self-assembled 4-(pyridine-4′-amido)thiophenol (PATP) monolayer modified gold electrode, was developed for the detection of glucose and hydrogen peroxide (H₂O₂) at neutral pH. The modified electrode was characterized by electrochemical and microscopic techniques. The non-enzymatic sensor exhibited a remarkable catalytic performance for glucose oxidation and H₂O₂ reduction. Chronoamperometry was used for the electrochemical determination of glucose and H₂O₂. The non-enzymatic sensing of glucose was realized with a linear response range from 0.001 to 0.5 mM with a detection limit of 0.1 μM (S/N = 3). The sensor also has a good performance for the electrocatalytic reduction of H₂O₂ with a linear response range from 0.02 to 0.9 mM with a detection limit of 0.03 μM (S/N = 3). In addition, [VO(acac)₂]–PATP–Au showed a good selectivity for glucose and H₂O₂ detection in the presence of potential interfering agents such as ascorbic acid, uric acid, L-dopa, L-cysteine and different ions like Na⁺, K⁺, Cl⁻ etc. The kinetic parameters such as the electron transfer coefficient and the catalytic reaction rate constant were also determined for glucose and H₂O₂. Finally, the modified electrode was used to achieve quantitative detection of glucose and H₂O₂ in blood and milk, respectively for practical applications.