Selective extraction and preconcentration of chromium using Moringa oleifera husks as biosorbent and flame atomic absorption spectrometry

In this study a new method for selective extraction and preconcentration of chromium in water using Moringa oleifera husks as the solid phase with a flow injection system and detection by flame atomic absorption spectrometry was developed. The behavior of Cr(III) and Cr(VI) adsorption onto Moringa oleifera husks allowed the selective separation of Cr(III) in the pH range of 7-9 and Cr(VI) in the pH range of 1-2. The operational variables of the preconcentration system were optimized through full factorial and Doehlert designs. The limits of detection for Cr(III) and Cr(VI) were 1.92 and 2.45 mu g L-1 and the precision were below 1.63% and 0.08%, respectively. Results for recovery tests using different water samples were higher than 88% for Cr(III) and 81% for Cr(VI). (C) 2012 Elsevier B.V. All rights reserved.