A hydrogen peroxide biosensor based on multiwalled carbon nanotubes-polyvinyl butyral film modified electrode

A novel approach to construct a amperometric biosensor for determination of H₂O₂ is described. Horseradish peroxidase (HRP) as a base enzyme was immobilized into the mixture of multiwalled carbon nanotubes (MWNTs) and polyvinyl butyral (PVB). Taking the classical hydroquinone as mediator, cyclic voltammetry and amperometric measurements were used to study and optimize the performance of the resulting H₂O₂ biosensor. The effect of the concentration of MWNTs, HRP, hydroquinone, solution pH, and the working potential of amperometry on the electrochemical biosensor was systematically studied. The results showed that the fabricated biosensor demonstrated significant electrocatalytic activity for the reduction of hydrogen peroxide with wide linear range from 0.000832 to 0.6 mM, and low detection limit 0.000167 mM (S/N = 3) with fast response time less than 8 s. The apparent Michaelis–Menten constant was determined to be 0.049 mM. Additionally, the biosensor exhibited high sensitivity, rapid response and good long-term stability.