Vapour-phase behaviour of slurries in electrothermal atomic absorption spectrometry

Abstract

The evolution of molecular and atomic vapours during the atomization of slurries has been followed using an ultraviolet spectrophotometer with diode-array detection. Certified reference materials with an appropriate inorganic matter content were vaporized at 1700 °C, which gave rise to SiO molecules with a structured absorption between 200 and 250 nm. The same slurries, but prepared with HNO₃, when vaporized at the same temperature produced Al₂C₂ species. Atomization at 2200 °C led to the fast evolution of SiO and Al species and to a rapid change in spectral behaviour of the vapour phase. Above 280 nm deuterium-arc background correction was effective at reducing non-specific absorption, while at lower wavelengths Zeeman-effect background correction was more effective for the analytical lines in the spectral range of SiO and Al species.