Examination of Interferences in the Stripping Voltammetric Determination of Trimethyllead in Seawater by Polarography and Mercury-199 and Lead-207 Nuclear Magnetic Resonance Spectrometry

A. M. Bond, J. R. Bradbury, P. J. Hanna, G. N. Howell, H. A. Hudson, Stan Strother, M. J. O'Connor

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Abstract

Detailed Investigations using polarography and pulse Fourier transform multlnuclear magnetic resonance spectrometry show that mercury(II) Ions react with trimethyllead cations In seawater and other aqueous media according to the equation Hg2+ + [(CH3)3Pb]+ → CH3Hg+ + Pb2+ + 2CH. This reaction may Invalidate proposed methods for determining trimethyllead by anodic stripping voltammetry at a glassy carbon electrode (In situ deposition of mercury) since mercury(II) Ions are added In relatively high concentrations to the sample solution as part of the analytical procedure. While stripping techniques at the hanging mercury drop electrode do not suffer from this kind of Interference, under oxygen-free conditions, transalkylation reactions at the electrode surface Interfere with the direct determination of [(CH3)3Pb]+ In the presence of Inorganic Pb(II) and double standard addition experiments are required to simultaneously determine both forms of lead. These experiments are Inherently Inaccurate and chromatographic or other separation techniques are recommended as a precursor for determining [(CH3)3Pb]+ In the presence of Inorganic Pb(II).

Original languageEnglish
Pages (from-to)2392-2396
Number of pages5
JournalAnalytical Chemistry
Volume56
Issue number13
DOIs
Publication statusPublished - Nov 1984
Externally publishedYes

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