A New Mode of Homogeneous Liquid-liquid Microextraction (HLLME) Based on Ionic Liquids: In Situ Solvent Formation Microextraction (ISFME) for Determination of Lead

A simple in situ solvent formation microextraction method based on use of ionic liquid (IL) as an extractant solvent and sodium hexafluorophosphate (NaPF6) as an ion-pairing agent was proposed for the concentration of trace levels of lead. In this method lead was complexed with N-phenylbenzo-hydroxamic acid (PBHA) and extracted into an ionic liquid phase. After phase separation, the enriched analyte in the final solution is determined by flame atomic absorption spectrometry. ISFME is a fast, simple and suitable method for extraction and concentration of inorganic such as metal ions from sample solutions containing a high concentration of salts. The influences of the analytical parameters on the microextraction efficiency were investigated and optimized. Under the optimum conditions, the limit of detection (3s) and the enhancement factor were 0.1 mu g L-1 and 70, respectively. The relative standard deviation (R.S.D) was obtained 1.3%. The accuracy of the method was confirmed by analyzing certified reference materials. The presented method was successfully applied for the determination of lead in water samples.