The morphological studies of the GCE-MWCNTs were carried out by scanning electron microscopy (SEM) using Philips SCI quanta 400 instrument. Scanning electron micrograph is shown in Fig. 2. In the figure MWCNTs could be seen in the form of tubes some of which twisted together. MWCNTs with an average diameter of approximately to 200 nm were observed on the GCE-MWCNTs surface. The modification of glassy carbon electrode using multi-walled carbon nanotubes not only enlarges the ratio surface area of the electrode surface but also improves the electron transfer rate between the electrode surface and the bulk solution.