Improving the Signal Strength and Detection Limits of Laser-Induced Breakdown Spectroscopy

Abstract

Over the past two decades, there are multiple techniques introduced for enhancing the LIBS signal strength in order to improve the sensitivity and precision of the LIBS measurements. The purpose of this book chapter is to provide an overview of the basic components of the LIBS system and the different experimental strategies employed for enhancing the LIBS signal strength with a special emphasis on Nanoparticle Enhanced Laser-Induced Breakdown Spectroscopy (NELIBS). The NELIBS is a relatively new technique for enhancing the LIBS signal intensity and improving its sensitivity and detection limit. The considerable signal enhancement with minimal sample preparation has increased the popularity of this technique in analytical chemistry. Our recent observations on LIBS signal enhancement using colloidal silver nanoparticles (10 nm) on brass sample have been described here. A Q-switched Nd: YAG laser operating at a wavelength of 1064 nm, pulse duration = 7 ns with 90 mJ/pulse energy, was used as a common irradiation source for both LIBS and NELIBS measurements. Both spectra were recorded in a similar experimental condition and then compared to estimate the signal enhancements. A clear enhancement of spectral intensities up to 4-times has been observed in the case of NELIBS compared to conventional LIBS. The temporal evolution of the NELIBS plasma has also been investigated, and the results are presented here.