Analysis of geological materials by inductively coupled plasma mass spectrometry with sample introduction by electrothermal vaporisation. Part 2. Determination of thallium

Abstract

The application of inductively coupled plasma mass spectrometry with sample introduction by electrothermal vaporisation to the determination of TI in geological materials was studied. Two commonly used decomposition procedures, both employing HF and oxidising acids but one also incorporating fusion of the residue with LiBO₂, were tested. Good accuracy and precision were achieved in the direct analysis of the acid leachates, as demonstrated by the results for international reference materials. A detection limit of 9 ng g^–1 of TI was obtained, with an average precision of 4% RSD in the range 5–1400 ng g^–1. However, a spectral interference caused by a high concentration of Pb necessitated separation of TI by the extraction into isobutyl methyl ketone (IBMK) prior to analysis of those samples whose Pb contents were greater than 500 µg g^–1.