Preparation of amperometric glucose sensor based on electrochemically polymerized films of indole derivatives

A polymer-modified electrode was prepared by the electrochemical polymerization of 5-hydroxytryptamine (H-TP); glassy carbon (GC) electrode (disk, 3 mm in diameter) was immersed into a 5 mM H-TP containing 0.1 M phosphate buffer (pH 7.0), and a potential of +1.0 V versus Ag/AgCl was applied for 30 s. After polymerization, glucose oxidase (GOD) was immobilized by dropping GOD solution (1 wt.%, 20 μl) and glutaraldehyde (0.1 wt.%, 20 μl) solution and drying for 4 h. After immobilizing enzyme, the electrode was used for the detection of glucose by applying a +1.0 V versus Ag/AgCl on the base electrode. Immediately after the addition of glucose, oxidative current was increased and reached a steady-state within 10 s. The current response was linear to the glucose concentration up to 5 mM. The lower detection limit was 0.1 mM glucose (S/N = 3). The electrode would be used as a glucose biosensor.