Kinetic study of the oxidation of some catecholamines by digital simulation of cyclic voltammograms

✍ Scribed by Abbas Afkhami; Davood Nematollahi; Lida Khalafi; Mohammad Rafiee

• Publisher: John Wiley and Sons
• Year: 2004
• Tongue: English
• Weight: 160 KB
• Volume: 37
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/kin.20046

✦ Synopsis

Abstract

Electrochemical oxidation of some catecholamines such as dopamine (1), L‐dopa (2), and methyldopa (3) has been studied in various pH values, using cyclic voltammetry. The results indicate participation of catecholamines (1–3) in intramolecular cyclization reaction to form the corresponding o‐quinone derivatives (1d–3d). In various pHs, based on ECE mechanism, the observed homogeneous rate constants (k~obs~) of cyclization reaction were estimated by comparing the experimental cyclic voltammetric responses with the digital‐simulated results. Also, the cyclization rate constants (k~cyc~) were calculated using microscopic acidic dissociation constant of ammonium groups. The significant differences in electrochemical behavior, k~obs~ and k~cyc~, of L‐dopa (2) and methyldopa (3) with dopamine (1) are due to the effects of the side chain carboxyl group. © 2004 Wiley Periodicals, Inc. Int J Chem Kinet 37: 17–24, 2005