Quantitative element mapping of Mg alloys by laser ablation ICP-MS and EPMA

Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has been successfully applied to quantitatively map the lateral elemental distribution of trace elements in multi-phase magnesium-based alloys. A lateral resolution of 32 μm was achieved with limits of detection in the lower mg kg−1 range for Ti, Cr, Mn, Fe, Co, Ni, and Cu in such materials. Quantification of elements by LA-ICP-MS was carried out using a sum normalization calibration procedure. Multi-element mappings of an area of 350 μm × 350 μm were performed by LA-ICP-MS and results for the main elements Mg, Al, and Zn were compared to electron probe microanalysis (EPMA) measurements of the same sample area. The agreement for Mg was 2.2% between the two techniques. The influences of the laser parameters, like repetition rate and laser spot size were studied and the conditions were optimized for single spot analysis to achieve high lateral resolution capabilities.