Determination of isoproterenol and uric acid by voltammetric method using carbon nanotubes paste electrode and p-chloranil

An electrochemical method is described for the voltammetric determination of isoproterenol in the presence of uric acid using p-chloranil-carbon nanotubes paste electrode. Cyclic voltammetric, chronoamperometric, and electrochemical impedance spectroscopic methods have used to investigate the suitability of p-chloranil as a mediator for the electrocatalytic oxidation of isoproterenol at pH = 10.5. Using differential pulse voltammetry, isoproterenol (ISPT) and uric acid (UA) in a mixture can be measured simultaneously and individually with a potential difference of 360 mV. The electrocatalytic currents increase linearly with ISPT and UA concentrations over the concentration ranges of 0.015-100 mu mol L(-1) ISPT and 3.0-310 mu mol L(-1) UA. The detection limits for ISPT and UA were equal to 0.009 and 2.3 mu mol L(-1), respectively. The diffusion coefficient and the kinetic parameters such as electron transfer coefficient and heterogeneous rate constant were determined for ISPT, using the electrochemical approaches. The proposed method was successfully applied to the determination of isoproterenol in both ampoule and urine samples. (C) 2011 Elsevier B.V. All rights reserved.