Effect of particle size distribution in laser-induced breakdown spectroscopy analysis of mesoporous V–SiO2catalysts

Abstract

In this paper, the effect of particle size on Laser-Induced Breakdown Spectroscopy (LIBS) analysis of mesoporous V–SiO₂ catalyst samples was investigated. The measurements were realized on three LIBS devices with different parameters. Concentrations of V in samples used for LIBS experiments previously determined by inductively coupled plasma-optical emission spectroscopy (ICP-OES) varied from 1.2 to 4.7 w/w%. Granulometry of silica samples was modified by two grinding methods (conventional vibration mill and cryogenic mill) and three sets of samples with different particle size distributions were obtained. Ground samples were then deposited in the form of a thin layer on the adhesive tape and analysed by LIBS. Curves describing the relationship between the vanadium concentration and the corresponding intensity of LIBS signal (C–I curves) were constructed for all three groups of samples, with different granulometry profiles measured with three different LIBS devices. The C–I curves for samples with narrow particle size distribution showed the highest values of slopes. Detection limits achieved were in the range 0.063–0.012% (w/w). The best LOD values were obtained for samples with the lowest mean particle size.