Direct atomic spectrometric analysis by slurry atomisation. Part 4. Determination of selenium in coal by electrothermal atomisation atomic absorption spectrometry

Abstract

The determination of selenium in whole powdered coal without sample dissolution is described. The sample was introduced into a graphite furnace as a slurry for analysis by atomic absorption spectrometry. The coal was slurried in nickel nitrate (matrix modifier), nitric acid and ethanol (wetting agent). The effects of the type of background correction (continuum source or Smith-Hieftje), the furnace programme, the various matrix modifiers and air ashing, particularly on a spectral interference from iron, were investigated. Method calibration was achieved using aqueous standards and sample destruction was carried out in situ in the furnace. The preferred method used Smith-Hieftje background correction, the 196.0-nm resonance line and in situ air ashing. Selenium was successfully determined in four certified reference material coals with a typical relative standard deviation of 5% at the 1 µg g^–1 level. The limit of detection (2σ) of the method is 0.05 µg g^–1.