Direct electrochemistry of cytochrome c at a glassy carbon electrode modified with single-wall carbon nanotubes.

The electrochemistry of horse heart cytochrome c was studied by cyclic voltammetry at a glassy carbon electrode modified with single-wall carbon nanotubes (SWNTs). A pair of well-defined redox waves was obtained in cytochrome c aqueous solution at an activated SWNT film-modified electrode. The optimal conditions for activating the SWNT film-modified electrode has been determined. The electrode reaction of cytochrome c is a diffusion-controlled process. The peak current increases linearly with the concentration of cytochrome c in the range from 3.0 x 10(-5)-7.0 x 10(-4) M. The detection limit is 1.0 x 10(-5) M. The activated SWNT film was characterized by scanning electron microscopy. Furthermore, interaction of cytochrome c with adenine was characterized by electrochemical and spectral methods.