Assessment of the concentration of Cr, Mn and Fe in sediment using laser-induced breakdown spectroscopy

Abstract

In the present study, laser-induced breakdown spectroscopy (LIBS) has been applied for the determination of levels of Cr, Mn and Fe in sediment samples and the results have been compared with that of flame-atomic absorption spectroscopy (F-AAS). Fourteen sediment samples were collected from Tinishu Akaki River (TAR), Addis Ababa, Ethiopia. Pellets of 24 mm in diameter and 3-5 mm in thickness were prepared using a manual hydraulic press under a pressure of 8000 psi by mixing finely ground sediment samples with boric acid. The concentrations of Cr, Mn and Fe were successfully determined by Q-switched Nd:YAG laser at 1064 nm. Quantification of these metals was conducted against certified reference materials of sediments and soils. The LIBS results for the elements varied from 0.060-0.707 mg/g for Cr, 0.895-3.64 mg/g for Mn and 26.9-71.8 mg/g for Fe. The F-AAS results varied from 0.061-1.37 mg/g for Cr, 1.24-4.46 mg/g for Mn and 49.0-83.3 mg/g for Fe. TAR was found to be heavily polluted with Cr. © 2013 Chemical Society of Ethiopia.