Hydrogen peroxide biosensor based on the immobilization of horseradish peroxidase onto a poly(aniline-co-N-methylthionine) film

• An amperometric H2O2 biosensor based on poly(aniline-co-N-methylthionine) was created.
• Poly(aniline-co-N-methylthionine) can enhance and fasten direct electron transfer kinetics of horseradish peroxidase.
• Fast and sensitive detection of H2O2 with a wide linear range and long storage stability.

In this present work, we developed a novel hydrogen peroxide (H2O2) biosensor fabricated using electrochemical doping to immobilize hydrogen peroxidase (HRP) in a new conducting polymer, poly(aniline-co-N-methylthionine) (PAN-PNMThH). Amperometric detection of H2O2 was evaluated by holding the PAN-PNMThH HRP electrode at −0.25 V (versus saturated calomel electrode (SCE)). PAN-PNMThH showed excellent redox activity and high porosity and acted as an electron transfer mediator. The biosensor had a wide linear response range from 5.0 μM to 60.0 mM H2O2 with a sensitivity of 35 mA M−1 cm−2, a detection limit of 3.2 μM (signal-to-noise ratio of 3) and an apparent Michaelis constant (KM) of 2.79 mM. The biosensor possessed good analytical performance and storage stability.