Laser-induced breakdown spectroscopy and inductively coupled plasma-mass spectrometry for determination of Cr in soils from Brits District, South Africa

Abstract

ABSTRACT. Laser-induced breakdown spectroscopy (LIBS) is an emerging analytical technique, which can be used to perform elemental analysis of any material, irrespective of its physical state. In this study, the LIBS technique has been applied for quantification of total Cr in soil samples collected from polluted areas of Brits, North West Province, South Africa. A Q-switched neodymium-yttrium aluminium garnet (Nd-YAG) laser (10 Hz, λ = 1064 nm) was employed for generation of a laser-induced plasma on the surface of the soil sample. The atomic emission lines were recorded using an Andor Shamrock SR-303i spectrometer, fitted with an intensified charge-coupled device (ICCD) camera. Detailed investigation of experimental parameters such as gate delay time, gate width and laser pulse energy was conducted. Soil samples were dried, finely ground, sieved and thereafter pelletized before LIBS analysis. Calibration curve for the quantification of Cr was constructed using certified reference materials of soils and sediments. The concentrations of Cr in soil samples varied from 111 to 3180 mg/kg. In order to test the validity of the LIBS results, inductively coupled plasma-mass spectrometry (ICP-MS) was also employed for determination of Cr. The results obtained using LIBS were found to be in good agreement with those of ICP-MS.

Applications of laser‐induced breakdown spectroscopy for soil characterization, part II: Review of elemental analysis and soil classification

“…The LIBS technique was successfully used (i.e., good correspondence with the reference technique, low error and LOD below the regulatory guideline values) to quantify toxic elements in soils (Akhtar et al, 2018;Ambushe et al, 2015;Barbafieri, Pini, Ciucci, & Tassi, 2011;Bousquet et al, 2007;Chen, Hei, Yu, Chen, & Cai, 2018;Dell'Aglio et al, 2011;Gao et al, 2018;Gornushkin et al, 1997;Hilbk-Kortenbruck et al, 2001;Khumaeni et al, 2017;Kwak et al, 2009;Lazic, Barbini, Colao, Fantoni, & Palucci, 2001;Menegatti et al, 2017;Meng et al, 2015Meng et al, , 2017Multari et al, 1996;Nicolodelli et al, 2018;Popov et al, 2010Popov et al, , 2014Senesi et al, 2009;Sirven et al, 2006;Srungaram, Ayyalasomayajula, Yu-Yueh, & Singh, 2013;Wang et al, 2018;Wisbrun et al, 1993;Yi et al, 2018;Zaytsev et al, 2018). The technique has been more sensitive than the reference technique when optimized or used with signal enhancement methods (Akhtar et al, 2018;Gao et al, 2018;Gornushkin et al, 1997;Hilbk-Kortenbruck et al, 2001;Khumaeni et al, 2017;Meng et al, 2015;Popov et al, 2010Popov et al, , 2014Yi et al, 2018).…”

“…The problem with this approach is that the samples used to develop calibration models had little matrix variation and do not represent real soil samples. However, few papers considered a large sample set (Wang et al, 2018) or very distinct soil samples, even from various parts of the world (Ambushe et al, 2015), and managed to minimize the matrix effects. The main methods used for minimizing matrix effects were as follows.…”