Identification of Heavy Metals in SomeWater Sources in Khartoum State using Laser Induced Breakdown Spectroscopy

Abstract

In this work, Laser Induced Breakdown Spectroscopy (LIBS) was used to investigate, and identify, the heavy metals in samples of water collected from different places in Khartoum state during the period from 2013 to 2015. Eight water samples were used as study samples. The breakdown of the samples was induced by focusing a pulsed Nd: YAG laser at 532 nm, 2Hz Rpetion Rate, pulse duration of 10 ns, with different pulse energies: 60, 80, 100, and 120 mJ, respectively. The emission spectra of the samples plasma were collected via optical fiber and recorded by Ocean Optics 4000- spectrometer. The recorded spectra of the samples were analyzed using NIST data. The analysis of the spectra showed considerable amounts of neutral atoms like (Ni, As, Ru, Th, Zr, Tb, Eu, Li, I, Cu, Xe, K, He, Ne, Cs, Hg, Cr, Tl, Cl, Na, Fe, Na, Ra and Ca)elements in addition to the ions: (Ni+1, As+1, Th+1, Th+2, Zr+1, Cs+1, Cs+2, Cr+1, Cr+2 , Tl+1, Tl+2, Fe+1 and Fe+2). The heavy metals like:(Cr, Hg, and Tl) were appeared in the eight samples with nearly amounts, they are toxic metals harmful to human and environment. Also metals like: (Na, I, Cu and K) were appeared with different amounts in many samples. It can be concluded that LIBS technique proved to be, fast and accurate technique for the detection of heavy metals and can be used for the determination of its concentrations. A portable LIBS system for online analysis indifferent sites can be recommended for improvement of the environment.