Nanoparticle Enhanced Laser Induced Breakdown Spectroscopy: pushing LIBS beyond its limits

In this work the use of noble metal Nanoparticles (NPs) for enhancing the ablation efficiency, in terms of atomization of the ejected mass, is discussed both from a fundamental and applicative points of views. The effect of plasmonic resonance during laser ablation on target covered with plasmonic NPs systems has shown promising results in the case of LIBS and LA-ICP-MS, allowing an effective improvement of the sensitivity of the above mentioned techniques. For example, in the case of LIBS, sub-picograms detection can be easily achieved depositing Au-NPs or Ag-NPs, opening the way to sub-ppm analysis or to elemental quantification in an extremely limited portion of sample. This advatages is getting a growing interest in analytical chemistry and the number of papers devoted to Nanoparticle Enhanced LIBS (NELIBS) is drammatically increasing.This work is aimed to discuss the basic mechanisms during plasmon enhanced photo-ablation and, in turn, to present an overview of the laser-matter interaction at nanoscale. This description will be used to discuss the main questions in preparing sample for NELIBS and to rationalize the signal enhancement during elemental analysis. Several examples of practical applications in trace analysis of metallic alloys, liquid solutions, biological system and forensic sample will be described and discussed in order to give a complete idea of the potentialities of this new approach in laser ablation based techniques.