Ionic Liquid-based Ultrasound-Assisted In Situ Solvent Formation Microextraction Combined with Electrothermal Atomic Absorption Spectrometry as a Practical Method for Preconcentration and Trace Determination of Vanadium in Water and Food Samples

A new and practical sample enrichment method termed ionic liquid-based ultrasound-assisted in situ solvent formation microextraction (IL-UA-ISFME) was combined with electrothermal atomic absorption spectrometry (ETAAS) for preconcentration and trace determination of vanadium in real samples. In this sample enrichment methodology, a hydrophilic ionic liquid (IL) ([Hmim][BF4]) was added to the aqueous media containing an ion-exchange reagent (NaPF6), in order to obtain a hydrophobic IL ([Hmim][PF6]) as the microextraction solvent. The hydrophobic extraction solvent formed under these conditions was completely dispersed into the sample solution using ultrasonic radiation. Vanadium was complexed with N-benzoyl-N-phenylhydroxylamine (BPHA), and extracted into the IL phase during the dispersion of the hydrophobic IL. Main variables affecting the recommended method was studied in details and optimized. Under the optimum conditions, the combined methodology provided a linear dynamic range of 15-2,500 ng l(-1), a limit of detection (LOD) of 4.7 ng l(-1) and a relative standard deviation (RSD) of 4.0 %. The accuracy and validity of the method was checked by analyzing a certified standard reference material of water (SRM-1643e). Finally, the developed method was utilized for quantitation of vanadium in real water and milk samples.