Abstract

A newly conceived electrothermal vaporisation system using a tungsten boat furnace (TBF)–sample cuvette technique was applied for the direct analysis of rock samples with detection by inductively coupled plasma mass spectrometry (ICP-MS). Into this sample cuvette made of tungsten, the powdered rock sample and an aliquot of ammonium fluoride solution were placed and the cuvette was heated on a hot-plate for digestion. After the decomposition had been completed, the cuvette was positioned on the TBF. The analyte in the cuvette was vaporised and introduced into the ICP mass spectrometer. Since the solid samples could be decomposed to ash completely in the cuvette and the majority of siliceous components were expelled prior to measurement, the sensitivity was the same as that of aqueous standards. The most remarkable feature is that the small sample cuvette was utilised as a weighing dish, sample carrier, decomposition vessel and electrothermal vaporiser. Thus, the technique overcomes problems such as weighing small amounts of powdered samples, decomposition of solid materials, introduction of the samples into the TBF device and the easy removal of the residue. The method was successfully applied to the direct determination of lead in several standard rock samples.