Formation of tin and lead molecular species in electrothermal atomizers

The vaporization of slurries of Sn and Pb compounds has been followed by the continuous collection of the absorption spectra of the vapour phase. In the case of Sn the formation of SnO(g) has been observed during the vaporization of Sn and SnO2, and the formation of SnS(g) has been observed in the presence of CaSO4 and FeS2. In the case of Pb the only molecular species detected was PbS(g), that originated during the vaporization of PbSO4 in the presence of CaSO4. From the spectral data of the identified species, molecular absorption bands are selected to follow the vaporization process of each species at constant wavelength. The vaporization curves show that SnS(g) evolves before the appearance of Sn atomic vapours, but the formation of SnO(g) occurs contemporaneously with the appearance of the atomic vapours. The vaporization of PbS is slightly delayed in comparison with the formation of Pb atoms.