A model of non‐nernstian response in the determination of aluminum ions by indirect potentiometry

J. Catherine Ngila, Peter W. Alexander, D. Brynn Hibbert

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

Flow analysis data of the response of an aluminum wire electrode to fluoride into which Al3+ is added is modeled assuming a logarithmic response of the electrode to F and reaction of F with aluminum ions to give a series of complexes [AlFq](3−q)+ when q = 1,2,3,4,5,6. The solutions were maintained at pH 5.0 with acetic acid/acetate buffer. Other species modeled were the hydroxo complexes of aluminum [Alm(OH)n](3m−n)+ when m = 1, n = 1,2,3,4; m = 2, n = 2; m = 3, n = 4; m = 13, n = 32, and the acetate complex [Al2(OH)2OAc]3+. Protonation of F to HF and HF 2− was also considered. Three coefficients were required to fit the data, a constant and slope of the response of the electrode to free fluoride and a dispersion factor in the flow analysis. Published stability constants were used and no account was taken of ionic strength. The model may be used to predict optimum analysis conditions given an approximate aluminum concentration.

Original languageEnglish
Pages (from-to)947-951
Number of pages5
JournalElectroanalysis
Volume7
Issue number10
DOIs
Publication statusPublished - Oct 1995
Externally publishedYes

Keywords

  • Aluminum wire
  • Flow analysis
  • Indirect aluminum determination
  • Mathematical modeling

ASJC Scopus subject areas

  • Analytical Chemistry
  • Electrochemistry

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