Zdrojový dokument:Scientific papers of the University of Pardubice. Series A, Faculty of Chemical Technology. 22/2016
ISSN:1211-5541
Abstrakt:
An overview is dished up to show how the presence of a less noble metal ion in the
samples subjected to electroanalytical measurements may sometimes lead to a
positive effect on determinations of some analytes at the trace concentration level.
First, an unexpected behaviour of Sb-based electrodes is mentioned allowing one
its application also in the anodic potential range. A role of less noble metals is
documented on the stripping voltammetric determination of mercury(II) or
bismuth(III) at antimony film-coated carbon paste electrodes, where an apparent
catalytic effect caused by the presence of cadmium(II) was observed offering a
significant improvement of the analytical signal for both the cations. This phenomenon was attributed to the formation of intermetallic compounds during
the electrolytic accumulation at the electrode surface.
Very recently, a new approach was reported based on the preparation of
metal film electrodes that utilize the combination of ex situ and/or in situ plating
methods and the use of reversibly deposited mediator. By plating the metal film
onto the surface of glassy carbon electrode together with zinc acting as mediator
metal, followed by its subsequent oxidation and further deposition of the metal of
interest, a higher surface coverage of the electrode with metal particles could be
achieved. Application of the newly developed technique was demonstrated on the
determination of nickel(II) at a lead film electrode with the aid of adsorptive
stripping voltammetry, as well as on the determination of tin(IV) at a bismuth film
electrode when using square-wave anodic stripping voltammetry.