Preconcentration procedure using in situ solvent formation microextraction in the presence of ionic liquid for cadmium determination in saline samples by flame atomic absorption spectrometry

A simple in situ solvent formation microextraction methodology based on the application of ionic liquid (IL) as an extractant solvent and sodium hexafluorophosphate (NaPF6) as an ion-pairing agent was proposed for the preconcentration of trace levels of cadmium. In this method cadmium was complexed with O,O-diethyldithiophosphate (DDTP) and extracted into an ionic liquid phase. After phase separation, the enriched analyte in the final solution is determined by flame atomic absorption spectrometry (FAAS). ISFME is a simple and rapid method for extraction and preconcentration of metal ions from sample solutions containing a high concentration of salt. Some effective factors that influence the microextraction efficiency were investigated and optimized. Under the optimum experimental conditions, the limit of detection (3 s) and the enhancement factor were 0.07 mu g L-1 and 78, respectively. The relative standard deviation (R.S.D.) was obtained 2.42%. The accuracy of the method was confirmed by analyzing certified reference materials for trace elements in seawater (GBW (E) 080040 seawater). The proposed method was successfully applied for the determination of cadmium in water samples and food grade salts. Crown Copyright (C) 2010 Published by Elsevier B.V. All rights reserved.