Method development for direct quantitative analysis of high silicon content samples: laser-induced breakdown spectrometry and Total Reflection X-Ray Fluorescence

Abstract

Considering the refractory characteristic of high silicon content samples, such as rocks and slags that require use of different acid mixtures, high pressure and temperature to reach quantitative dissolution, the possibility of performing direct analysis seems to be a good alternative. Laser induced breakdown spectrometry (LIBS) has become an attractive and much explored technique in chemical analysis and, as a solid sampling technique, it allows analysis of solid samples dismissing the dissolution step. Despite all advantages, quantitative analysis of complex matrix by LIBS is not an easy task due to the complex nature of laser-sample and particle-plasma interaction, which cause an undesirable matrix effects. In these cases, the use of appropriate method calibration associated to optimization of instrumental and sample parameters are imperative. Considering quantitative analysis of complex matrix by LIBS is a challenge, the aim of this project is to evaluate the feasibility of using LIBS to perform quantitative measurements of some macro and microelements in high silicon content samples such as rocks and slags. We also intend to evaluate and compare the performance of total reflection X-ray fluorescence (TXRF) in the direct analysis of these samples. Although this technique is widely used in direct solid samples analysis, the influence of particle size on the analytical results as well as the interference of major elements over the minor one should be understood to makes quantitative analysis feasible. (AU)