Synthesis, Characterization, and Application of 1-Methyl-2-hexylthioimidazolium Chloride Liquid for Solvent-based Microextraction (SBME) of Hg in Water Samples

In this study, a solvent-based method to the microextraction of Hg(II) ions is described, relying on the use of a synthesized/characterized imidazolium-based ionic liquid (IL), specifically 1-methyl-2-hexylthioimidazolium chloride ([C1C6Sim][Cl]), as a task-specific ionic liquid (TSIL) or a functionalized ionic liquid (FIL). The synthesized TSIL underwent characterization through 1HNMR and FTIR analyses. The TSIL, chelated with Hg(II) ions in the aqueous phase to form a hydrophilic Hg-TSIL complex, which was subsequently converted into a hydrophobic Hg-TSIL complex through anion exchange reactions using sodium tetrafluoroborate. To assess the microextraction method capability in analyzing real samples with complex matrices containing Hg(II) ions, the experimental conditions need to determined, followed by the determination the Hg(II) concentration values using cold-vapor flame atomic absorption spectrometry (CV-FAAS). Based on the obtained results, the limit of detection (LOD) and limit of quantification (LOQ) were determined to be 0.015 ng ml-1 and 0.078 ng ml-1, respectively. The precision, expressed as relative standard deviations (RSD%) for intra-day and inter-day measurements over seven replicates, was found to be 1.7% and 1.9%, respectively. Furthermore, a linear dynamic range (LDR) of 0.1–80 ng ml-1 was achieved. The optimized conditions facilitated evaluating the method validity. Ultimately, the method validity was confirmed through its successful utilization in determining of Hg(II) ions in various real water and wastewater samples.