Modification of a glassy carbon electrode with a bilayer of multiwalled carbon nanotube/benzene disulfonate-doped polypyrrole: application to sensitive voltammetric determination of olanzapine

A glassy carbon electrode was coated with a thin layer of multi-walled carbon nanotubes and subsequently was electro-polymerized with polypyrrole. The prepared electrode was used for the voltammetric determination of olanzapine (OLZ). The peak current of OLZ increases remarkably on the surface of the modified electrode. This is due to the large increase in the microscopic area of the electrode surface along with the strong adsorption of OLZ on the surface of the electrode. The film modifier was characterized by scanning electron microscopy, atomic force microscopy and cyclic voltammetry techniques. Experimental variables, such as deposited amount of nanotube suspension, pH of the supporting electrolyte, potential and time of the accumulation and the number of electro-polymerization cycles were optimized by monitoring the LSV responses toward OLZ. In the optimal conditions, the electrode showed a linear response to the concentration of OLZ within a 0.02-2.00 mu M range with a detection limit of 6.00 nM. The electrode shows advantages such as simple preparation, high stability and uniformity in the composite film and high sensitivity in response to the OLZ. The modified electrode has been applied for accurate determination of trace amounts of OLZ in pharmaceutical and clinical preparations.