Pressure-assisted ionic liquid dispersive microextraction of vanadium coupled with electrothermal atomic absorption spectrometry

A simple and new liquid-liquid dispersive microextraction termed pressure-assisted ionic liquid dispersive microextraction (PILDME) was developed for the concentration of trace levels of vanadium in real water samples followed by its quantification by graphite furnace atomic absorption spectrometry (GFAAS). We performed a pressure-induced dispersion of 1-butyl-3-methylimidazolium hexafluorophosphate [C₄mim][PF ₆] into the aqueous sample. Chloroform was used to decrease the dissolution and increase hydrophobicity of the ionic liquid to entrap vanadium in a labile hydrophobic chelate with 8-hydroxyqunioline (8-HQ). Several variables playing a vital role in the prescribed procedure were studied and optimized. With optimum experimental values of significant variables, the detection limit (LOD) and the enhancement factor (EF) were observed to be 20 ng L^-1 and 100, respectively. The precision of the method was checked by detection of the relative standard deviation (RSD) as 4.5% at a vanadium concentration of 0.5 μg L^-1. The validity and accuracy of the applied method were tested by vanadium extraction and quantification of the standard reference material "SLRS-4 Riverine water", and the results were found to be in good agreement with the certified values. The method was satisfactorily applied to real water samples.