Electrochemical sensor for procaine based on a glassy carbon electrode modified with poly-amidosulfonic acid and multi-walled carbon nanotubes

A glassy carbon electrode was prepared that was coated with a composite film containing electropolymerized poly(amidosulfonic acid) and multi-walled carbon nanotubes. It was used to study the electrochemical response of procaine by differential pulse voltammetry. The results indicate that the electrode exhibits a remarkable improvement in the oxidation peak of procaine, and this led to a simple and sensitive method for the electroanalytical determination of procaine. The peak current is proportional to the concentration of procaine from 80 nM to 1.0 A mu M. The detection limit is 25 nM (S/N = 3). The modified electrode was successfully applied to the direct determination of procaine in pharmaceutical formulations.