Amperometric Biosensor for Hydrogen Peroxide, Using Supramolecularly Immobilized Horseradish Peroxidase on the β‐Cyclodextrin‐Coated Gold Electrode

Horseradish peroxidase, previously modified with 1-adamantane moieties, was supramolecularly immobilized on gold electrodes coated with perthiolated β-cyclodextrin. The functionalized electrode was employed for the construction of an amperometric biosensor device for hydrogen peroxide using 1 mM hydroquinone as electrochemical mediator. The biosensor exhibited a fast amperometric response (6 s) and a good linear response toward H2O2 concentration between 12 μM and 450 μM. The biosensor showed a sensitivity of 1.02 mA/M cm2, and a very low detection limit of 5 μM. The electrode retained 97% of its initial electrocatalytic activity after 30 days of storage at 4 0C in 50 mM sodium phosphate buffer, pH 7.0.