VAPOR-PHASE BEHAVIOR OF SLURRIES IN ELECTROTHERMAL ATOMIC-ABSORPTION SPECTROMETRY

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-degrees-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-degrees-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.