US EPA

1452263 

Journal Article 

Electrochemical oxidation of 6-hydroxyquinoline on a glassy carbon paste electrode: Voltammetric and computational study 

Stevic, MC; Ignjatovic, LM; Ciric-Marjanovic, G; Marjanovic, B; Barek, J; Zima, J 

2012 

1 

Journal of Electroanalytical Chemistry and Interfacial Electrochemistry
ISSN: 0022-0728 

677 

69-77 

10.1016/j.jelechem.2012.04.030 

WOS:000306728700010 

http://://WOS:000306728700010
Exit
 

Experimental study of the electro-oxidation behavior of 6 hydroxyquinoline (6HQ) has been performed using cyclic voltammetry (CV) on a glassy carbon paste
electrode (GCPE). The theoretical study of the 6HQ electrochemical oxidation mechanism, based on
the AM1 semi-empirical quantum chemical computations of the heats of formation and ionization
energy of reaction intermediates, taking into account influence of pH and solvation effects, has
also been conducted. It was established that a two-electron, irreversible process, controlled by
diffusion of electroactive species, is responsible for an oxidation peak of 6HQ that appears in
all cyclic voltammograms recorded on a clean electrode, in solutions of pH range 2-12, with a
supporting electrolyte of Britton-Robinson buffer/methanol. A single-electron oxidation of 6HQ
leads, depending on pH, to the formation of various free radical species that combine to make C5
-C5 coupled 6HQ dimers which, after being oxidized once more, give quinonoid-type compounds. The
irreversible electrochemical oxidation of 6HQ does not stop after the dimerization step but
proceeds further to the formation of oligo/poly(6HQ). The optimum conditions for Differential
Pulse Voltammetry (DPV) determinations were established and it was shown that for more sensitive
quantitative determinations Adsorptive Stripping Differential Pulse Voltammetry (AdSDPV) can be
used. (C) 2012 Elsevier Ltd. All rights reserved. 

6-Hydroxyquinoline; Electrochemical oxidation; Glassy carbon paste electrode; Cyclic voltammetry; Computational electrochemistry