Electrocatalysis and voltammetric determination of dopamine at a calix[4]arene crown-4 ether modified glassy carbon electrode

Abstract

A sensitive and selective electrochemical method for the determination of dopamine (DA) was developed using a calix[4]arene crown-4 ether (CACE) film modified glassy carbon electrode (GCE).The modified electrode exhibited good electrocatalytic activity for electrochemical oxidation of DA in the pH 6.00 Britton-Robinson buffer solution, and ascorbic acid (AA) did not interfere with it. The diffusion coefficient (D = 2.1 × 10-5 cm2 s-1), and the kinetic parameter such as the electron transfer coefficient (α = 0.54) of DA at the surface of CACE were determined using electrochemical approaches. The catalytic oxidation peak currents showed a linear dependence on the DA concentration and a linear analytical curve was obtained in the range of 2.0 × 10-5-1.0 × 10-3 M of DA with a correlation coefficient of 0.9990. The detection limit (S/N = 3) was estimated to be 3.4 × 10-6 M. This method was also examined for the determination of DA in an injection sample. In addition, effects of possible interferences were investigated. The present work shows the potential of the proposed method for the fabrication of a modified electrode, as it can be effectively used for voltammetric detection of DA. © 2007 Wiley-VCH Verlag GmbH & Co. KGaA.