Coulometric titration study of the redox behavior and precise determination of hexachloroiridate(IV) ion and its monoaquo-chloro complex with electrogenerated bi-intermediates

摘要

The redox behavior of IrCl62- and Ir(H2O)Cl-5(-) ions is investigated. Based on the reversibility of the IrCl62-/IrCl63- couple, the reusable reduction and oxidation titrations of iridium(IV,III) can be realized in the same HCl solution with electrogenerated CuCln(n-1)- and Cl-2 as bi-intermediates, using biamperometric end point detection. The first reduction titration among the determinations of IrCl62- can be used for precise coulometric analysis. For the determinations of 0.5-5.0 mg of iridium, the relative average errors of the results are less than or equal to+/-0.06%, and the relative standard deviation (n=5-6) is 0.18-0.04%. The method is applied to the determination of iridium in the metal and its compounds. (C) 2000 Elsevier Science B.V. All rights reserved. [References: 12]