Polarographic and voltammetric determination of selected triazine-based azo dyes with different reactive groups

Jiří Barek, Arnold G. Fogg, Josino C. Moreira, M. Valnice B. Zanoni, Jiří Zima

Research output: Contribution to journalArticlepeer-review

37 Citations (Scopus)

Abstract

Mechanisms are suggested for the polarographic reduction of five triazinyl azo dyes differing only in their potentially reactive group, and optimum conditions are given for their polarographic and voltammetric determination. The Limit of determination using a static mercury drop electrode was around 1 x 10-6 mol l-1 for tast polarography and 2 x 10-8 mol l-1 for differential pulse polarography. Using a hanging mercury drop electrode, the limit of determination was around 1 x 10-8 mol l-1 for differential pulse voltammetry and around 2 x 10-10 mol l-1 for adsorptive stripping voltammetry. The reduction process of the azo group is used in all cases. Two of the dyes, viz. -Cl and -SCH2CH2OH derivatives, exhibit another reduction process at more negative potentials, which is shown to be due to a 2e- reduction of the leaving group/triazine bond followed immediately by a 2e- reduction of a C=N bond in the triazine ring. With 3-carboxypyridyl, methoxy and amino derivatives the reduction in triazine region is overlapped by the reduction of base electrolyte.

Original languageEnglish
Pages (from-to)31-42
Number of pages12
JournalAnalytica Chimica Acta
Volume320
Issue number1
DOIs
Publication statusPublished - 20 Feb 1996
Externally publishedYes

Keywords

  • Azo dyes
  • Polarography
  • Triazine-based azo dyes
  • Voltammetry

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biochemistry
  • Environmental Chemistry
  • Spectroscopy

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