Application of a New Synthesized Ionic Liquid Based on Pyrrolidinium for Microextraction of Trace Amounts of Cr(VI) Ions in Real Water and Wastewater Samples

A novel pyrrolidinium based-task-specific ionic liquid was successfully synthesized and characterized to specific complexation of Cr(VI) ions in aqueous media. In fact, by the use of a powerful in-situ solvent formation microextraction technique, trace levels of Cr(VI) ions in some real water and wastewater samples were determined. The microextraction of Cr(VI) ions was carried out by complexation of Cr⁶⁺ ions with ionic liquid of (1-(2-(quinolin-8-yloxy)ethyl)pyrrolidinium chloride) abbreviated as [QPyr][Cl]. A complexation between [QPyr][Cl] as carrier with Cr(VI) ions as analyte in aqueous solution system was done to transfer of analyte to the non-aqueous phase and finally the determination of Cr(VI) ions in aqueous solution (before and after the above procedure) was performed by atomic absorption spectrometry. Analytical parameters affecting the microextraction system were optimized by using the response surface methodology (RSM). The resulting equation was used to draw response surface plots for prediction of the extractive behavior of the Cr(VI) ions and to find the optimal extraction conditions. At optimized conditions, the calibration curve was linear in the range 50–750 ng/L; the limit of detection of 5.5 ng/L and the relative standard deviation of 2.9% for seven replicate determinations were obtained. As a result, the technique was successfully being applied for the determination of Cr(VI) in some water and wastewater samples with satisfactory recoveries.