Voltammetric study of the oxine-based extractant Kelex 100

The electroanalytical study of the behavior of 7-(1′-vinyl-3′,3′,5′,5′-tetramethylhexyl)-8-quinolinol, the active component of the commercial extractant Kelex 100 (Ashland Chemicals), at a glassy carbon electrode has been carried out using different voltammetric techniques. The compound is oxidized giving rise to a voltammetric peak in the pH range 1.03–7.27. The plot of the variation Ep versus pH shows two straight lines intercepting at 3.46, which corresponds to the pKai value of the component. The oxidation process of the compound is irreversible (ān = 1.32) and predominantly diffusion controlled, although with an important adsorptive component. The electrode process can be attributed to the oxidation of the hydroxyl group of the quinolinic ring. A voltammetric method for the determination of the extractant has been developed.