ANALYSIS OF ALUMINUM-ALLOYS USING INDUCTIVELY-COUPLED PLASMA AND GLOW-DISCHARGE MASS-SPECTROMETRY

The application of inductively coupled plasma mass spectrometry (ICP-MS) and glow discharge mass spectrometry (GD-MS) to the analysis of aluminium alloys is presented. The spectral characteristics of these two techniques are compared and contrasted. For the most part GD mass spectra are simpler than ICP mass spectra in that species originating from the components of air, water and solution solutes are essentially absent in GD spectra. However, GD spectra show the presence of multiply charged Ar species, and matrix and analyte based argide species are more prevalent than oxide species, the opposite being the case with the ICP. For both techniques, potential spectral interferences are evaluated and matrix effects are illustrated. For ICP-based analyses, it is shown that matrix effects can be minimized by adjustment of the nebulizer gas flow rate and by the use of an internal standard which is easy to add to the dissolved samples. For GD-based analyses, a matrix effect exists between low and high alloy aluminium samples and it is shown that the signal from AlAr can be used as an internal standard to minimize this matrix effect. Finally both techniques were applied to the analysis of a range of Alcan and Alcoa aluminium standards.