Selective determination of chromium(VI) ions using in-tube electro-membrane extraction followed by flame atomic absorption spectrometry

In the present work, a novel and efficient method, namely in-tube electro-membrane extraction followed by flame atomic absorption spectrometry (IEME-FAAS), is used for the selective determination of chromium(VI) ions in some environmental samples. In this approach, which is based upon the electro-kinetic migration of ionized compounds, by applying an electrical potential difference, the analyte is extracted from an aqueous sample solution through a supported liquid membrane (SLM) into an acceptor solution. A thin polypropylene (PP) sheet placed inside a tube acts as a support for the membrane solvent used, and 100 mu L of an aqueous acceptor solution is separated by this solvent from 5.0 mL of an aqueous donor solution. In order to achieve the best extraction efficiency, the effective parameters involved including the voltage magnitude, SLM solvent, extraction time, and pH range are optimized. Under the optimized experimental conditions, the IEME-FAAS method provides a good linearity in the range of 10.0-600 ng mL(-1), a low limit of detection (3.0 ng mL(-1)), and good extraction repeatabilities (RSDs below 8.6%, n = 5). Finally, the developed method is used for the selective determination of chromium(VI) ions in the tap, river, and mineral water samples. (C) 2017 Elsevier B.V. All rights reserved.