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.