Separation, Preconcentration and determination of Hg (II) Ion in Water Samples by Cloud Point Extraction Technique Coupled with UV-VIS Spectrophotometry using a New Complexing Agent

In this study a cloud-point extraction process using non-ionic surfactant Triton X-114 for extraction of mercury (II) from aqueous solutions was developed. The method is based on the complex formation of Hg (II) with benzyl (pyridin-2-yl) methylcarbamodithioate at pH 5.5. After preconcentration and dilution of the surfactant-rich phase, the enriched analyte was determined by spectrophotometer. The effects of different parameters such as concentration of surfactant, electrolyte, temperature and pH on the cloud point extraction were studied in detail and a set of optimum conditions were established. Under the optimum conditions, the calibration graph was linear in the range of 0.25–3 μg mL-1 with detection limit of 0.02 μg mL^-1. The precision (R.S.D. %) for 1 μg mL^-1 of Hg (II) was 1.6% (n=5) and the preconcentration factor was found to be 20. Under the presence of foreign ions, no significant interference was observed. Finally, the proposed method was applied successfully for the determination of Hg (II) in real water samples.