Laser-Induced Breakdown Spectroscopy Optimization Using Response Surface Methodology

Abstract

Laser-induced breakdown spectroscopy (LIBS) is a modern analytical technique that is capable of fast, multi-elemental, lowcost and environmental friendly analysis, which does not require complex sample preparation. Albeit its potential, LIBS analysis still presents many limitations in terms of sensitivity and reproducibility, especially when analyzing complex matrices such as of sediments and soil samples. In order to reduce these matrix related effects, it is highly recommended that the system temporal parameters, which are responsible for controlling plasma evolution and signal collection, are optimized beforehand. In this work, we proposed the design of experiments (DOE) tool – specifically, the response surface methodology (RSM) – as an approach to optimize LIBS’s most important parameters (delay-time, interpulse delay, gate width and accumulated pulse). Signal-to-noise ratio (SNR) of the emission lines for Zn, Cd, Mg, Al, Ni, Cu, Ca, Cr, Sr, Fe were the response variable assessed during the procedure. The results showed that the RSM was an effective optimization tool for LIBS parameters and the final condition improved SNR ratios by up to a 48 ratio, when comparing to the not-optimal conditions.