Electrocatalytic Detection of Isoproterenol at a Ferrocene-Multiwall Carbon Nanotubes Paste Electrode

A sensitive and selective electrochemical method for the determination of isoproterenol (ISPT) was developed by using a ferrocene multi wall carbon nanotubes paste electrode (FCMWCNTPE). The fabrication of FCMWCNTPE and its electrocatalytic effect for electrochemical oxidation of ISPT were investigated by electrochemical impedance spectroscopy (EIS) and voltammetric methods. The cyclic voltammetric results indicate that multi wall carbon nanotubes (MCNTs) remarkably enhance the oxidation of ISPT in wide pH range of 2.0-5.0, which is leading to considerable improvement of anodic peak current for ISPT, and allow the development of a highly sensitive voltammetric sensor for determination of ISPT in pharmaceutical and urine samples. It has been found that under optimum condition (pH 5.0) in cyclic voltammetry, the oxidation of ISPT occurred at a potential about 140 mV less positive than that unmodified carbon paste electrode. The kinetic parameters such as electron transfer coefficient, alpha and catalytic reaction rate constant, k(h) were also determined using electrochemical approaches. Finally, differential pulse voltammetry (DPV) exhibited two wide linear dynamic ranges and a lower detection limit of 0.07 mu mol L-1 for ISPT.