A Multiwall Carbon Nanotubes Paste Electrode as a Sensor and Ferrocenemonocarboxylic Acid as a Mediator for Electrocatalytic Determination of Isoproterenol

A ferrocenemonocarboxylic acid modified carbon nanotubes paste electrode (FMAMCNTPE) was constructed and used as a fast and sensitive tool for the determination of isoproterenol (ISPT) at trace level. It has been shown by direct current cyclic voltammetry, double step chronoamperometry and electrochemical impedance spectroscopy (EIS) that this modified electrode can catalyze the oxidation of ISPT in aqueous solution. The kinetic parameters of the system including electron transfer coefficient, and rate constant for the chemical reaction between ISPT and the redox sites in FMAMCNTPE were also determined using the electrochemical approaches. In addition, differential pulse voltammetry (DPV) was used for quantitative analysis. DPV showed wide linear dynamic range (0.5 - 50.0 mu mol L-1 ISPT) with a detection limit of 0.2 mu mol L-1 ISPT. The relative standard deviation (RSD%) for ten successive assays of 5.0 mu mol L-1 ISPT was 1.9%. Finally, this method was also examined as a selective, simple and precise electrochemical sensor for the determination of ISPT in real samples such as drug and urine.