Nanoparticles-enhanced laser-ablation ICP-MS of metallic samples

This research shows a preliminary study of nanoparticles-enhanced LA-ICP-MS, which aims to obtain an analytical procedure in order to improve the analytical performance of the technique in terms of sensitivity and LOD, without any changes in the experimental configuration. The undoubted strength of this approach is represented by its simplicity, affordability and fast performance. Laser parameters or the type and flow of gas carrier can be changed to improve the ablation of the sample. Otherwise, the sample can be altered in order to increase its response to laser, preserving its chemical properties. This second method has been used, and in particular some drops of AuNPs colloidal dispersion were deposited on the sample’s surface, and the solvent evaporated before it had been ablated. A remarkable increase in the measured signal intensity is observed due to the presence of nanoparticles. In analogy of what has already proved with Laser Induced Breakdown Spectroscopy [1,2], when a critical number of NPs are deposited on the target surface, the laser pulse electromagnetic field induces the collective oscillation of the conduction electrons of the NPs that in turn results in a strong enhancement of the field. The latter allows to switch the seed electron production in the ablation process from multiphoton ionization to electron field emission. In this frame a more efficient and homogeneous ablation can be obtained. In this work preliminary results of this approach during LA-ICP-MS of metallic alloys are shown and discussed with a systematic comparison of conventional LA-ICP-MS and nanoparticle enhanced LA-ICP-MS