Electrochemical Properties of Carbon-Paste Electrodes Spiked with Some 1,4-Naphthoquinone Derivatives

Abstract

The preparation and aqueous electrochemistry of a carbon-paste electrode, modified by 1,4-naphthoquinone and some of its derivatives are described. From a calculation of the half-wave potential as a function of the pH, potential-pH diagrams were constructed for each compound. The values of the formal potentials and the pKa′ of some different redox and acid-base couples involved at various solution pHs were obtained. The influence of such substituents as methyl-, hydroxy-, chloro-, and amino- concerning the electrochemical behavior of surface 1,4-naphthoquinone is described. The electrochemical behavior of such electrodes was examined in buffered borate solutions and the formation of a complex between borate anion and o-naphthalenediols was characterized. Finally, the range of the pH at which the electrode function is consistent was determined.