Immobilization of Cytochrome c on Multi-Walled Carbon Nanotube-Poly(Vinysulfonic Acid) Composite Film and Its Application for Amperometric Determination of H2O2

We report the immobilization of Cytochrome c (Cyt c) on multi-walled carbon notube-poly(vinyl sulfonic acid) (MWCNT-PVS) composite film modified glassy carbon electrode (GCE) and its application as H2O2 sensor. The MWCNT-PVS film is a good matrix for the immobilization of Cyt c. The surface morphological studies by atomic force microscopy (AFM) and electrochemical impedance spectroscopy (EIS) characterization of the film confirmed the presence of Cyt c in the film. The cyclic voltammetric (CV) responses of Cyt c MWCNT-PVS in pH 7 exhibit prominent redox couple for the Fe-III/II redox process with a peak-to-peak separation (Delta E-p) of 55 mV. The composite film showed good electrocatalytic activity towards the reduction of H2O2 in pH 7. Amperometric i-t responses of M WCNT-PVS/Cyt c composite modified rotating disc glassy carbon electrode towards the H2O2 reduction were recorded at the applied potential of -0.2 V. The rotation speed was 1200 RPM. The modified electrode showed a wide linear range of detection from 10 x 10(-6) to 7.5 x 10(-4) M H2O2. The stable background current, quick response and wide linear range demonstrate the possibilities of the proposed film for its potential application in real sample analysis.