CHARACTERIZATION OF LEAD-OXIDES BY LASER MICROPROBE COUPLED WITH MASS-SPECTROMETRY IN RESONANT AND NONRESONANT MODE - APPLICATION TO AMORPHOUS SILICATES CONTAINING LEAD

The laser microprobe coupled with mass spectrometry (LMMS) is used to determine the oxidation state of amorphous silicates containing lead. In positive mode, the fingerprint spectra obtained for mixtures of lea d oxides and quartz sand are compared with those obtained by the analy sis of microparticles of PbO and PbO2 oxides. For these, the effect of the ionization laser wavelength is illustrated: the use of resonant d esorption/ionization processes (357.2 and 283.3 nm) allows to distingu ish both oxides. Applied to glass dust (lead oxide containing high ref ractive index: amorphous) coming from finishing workrooms of a glass m anufacture, this in situ analytical method using the 283.3 nm resonant wavelength leads to LMMS fingerprint spectra which present strong sim ilarities with PbO spectra.