Covalently immobilized toluidine blue/sol-gel film electrode for the amperometric determination of hydrogen peroxide

Herein, we report our attempt to covalently immobilize toluidine blue with 3-aminopropyltrimethoxysilane and develop a simple amperometric sensor for the determination of hydrogen peroxide. The immobilization of TB to the silane matrix was effected using glutaraldehyde as the cross-linker. The mediator immobilized silane was spin coated as a thin film on a graphite rod to get the modified electrode. The modified electrode was characterized using cyclic voltammetry and its applicability as a sensor was probed for the determination of H2O2. H2O2 reduction was observed at a reduced potential of -0.33 V and a linear relation was obtained for H2O2 in the concentration range of 4.04 x 10(-6) M to 2.81 x 10(-3) M with a detection limit of 1.62 x 10(-6) M and a correlation coefficient of 0.9996. Amperometric studies have revealed a rapid response at the modified electrode for H2O2 determinations under dynamic conditions.