Elemental fractionation of glass using laser ablation inductively coupled plasma mass spectrometry

Three laser wavelengths (1064, 532, and 266 nm) were employed for laser ablation at varied laser pulse energies to study the effect of irradiance and wavelength upon analytical results for laser ablation inductively coupled plasma mass spectrometry (LP,-ICP-MS). Two important results were observed and are reported here: (1) the intensity of the MS signal came to a local minimum when the laser focal point was on the sample surface, and (2) elemental fractionation based upon laser wavelength and laser pulse energy was observed. For the waste glass simulant studied, ablation with 1064-nm (IR) and 532-nm (green) radiation produced elemental fractionation that relates to the melting point of the elemental oxide, whereas with 266-nm (UV) ablation the response was independent of the elemental oxide melting point. At high laser powers, ablation at 266 nm produced an elemental bias based upon the mass of the elements. These observations suggest the use of ultraviolet radiation at low pulse energies to obtain improved analytical results.