Elemental Analysys of metallic samples by nanopartiles-enhanced laser-ablation ICP-MS

This conventional method of Solid sample analysis is very dirty and produces a lot of chemical waste. Conversely, laser ablation is a green technology because it does not require acid dissolution and does not generate chemical wastes. Moreover, LA-ICPMS technique presents other interesting features such as high spatial resolution, extended linear dynamic range, low detection limits, extremely small sample quantities required for analysis. We propose an analytical strategy to enhance the sensitivity of LA- ICPMS by the deposition of gold nanoparticles (AuNPs) on the surface of investigated samples. The undoubted strengths of this approach are represented by simplicity, low-cost budget and fast performance. The commercial LA-ICPMS set-up has not been changed in any way and laser parameters, type and flow of gas carrier is not modified to improve the ablation of the sample [1]. The sample surfaces have been altered by depositing metallic nanoparticle (NPs) colloidal dispersions, thus increasing their response to laser, but preserving their chemical properties. A consistent lowering of the breakdown threshold and a remarkable increase in the measured signal intensity have been observed. This has allowed to determine traces and ultratraces in many areas (environmental, forensic, clinical, cultural heritage, food analysis, ecc.). In the method developed, the drops of NPs can be put in a controlled manner on the sample surfaces and completely removed before the analysis by laser ablation. This represents a further advantage compared to the classical methods of sample analysis. The first results obtained with this technique in the analysis of metal matrices show enhancement of the signal of one order of magnitude for most of the analyzed metals. [1] Z. Wang, B. Hattendorf and D. Günther, J. Am. Soc. Mass Spectrom. 17 (2006) 641-651.