Sodium dithionite as a selective demasking agent for the complexometric determination of thallium

Prakash Shetty, A. Nityananda Shetty

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Sodium dithionite is proposed as a new demasking agent for the rapid and selective complexometric determination of thallium(III). In the presence of diverse metal ions, thallium (III) was first complexed with excess EDTA and the surplus EDTA was then titrated with a standard zinc sulphate solution at pH 5-6 (hexamine buffer) using Xylenol Orange as the indicator. The EDTA equivalent to thallium was then released selectively with sodium dithionite and back titrated with a standard zinc sulphate solution as before. Reproducible and accurate results were obtained in the range 4 - 100 mg of thallium with a relative error of ±27 % and a coefficient of variation (n = 6) of not more than 0.30 %. The effects of various diverse ions were studied. The method was applied to the determination of thallium in its complexes and in alloys.

Original languageEnglish
Pages (from-to)1357-1362
Number of pages6
JournalJournal of the Serbian Chemical Society
Issue number11
Publication statusPublished - 01-12-2005


All Science Journal Classification (ASJC) codes

  • Chemistry(all)

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