A Green Enrichment Method of Copper, Manganese and Nickel in Water Samples via Cloud Point Extraction

A new, cost-effective, and environmental-friendly cloud point extraction methodology was described for enrichment of copper, manganese and nickel in several water samples. The method involves the complexation of copper, manganese or nickel with ۲-amino-۶-(۱,۳-thiazol-۲-diazeyl)-phenol at pH ۷.۰, then extraction into Triton X-۱۱۴. After dilution of the surfactant-rich phase with acidified methanol, the enriched analytes concentration was estimated by flame atomic absorption spectrometry. Parameters that influenced cloud point extraction, such as pH, reagent, surfactant and nitric acid concentrations, centrifuge rate and time, temperature, incubation time, as well as interferences were evaluated and optimized. The preconcentration factor was ۱۰۰, enrichment factors were ۱۴, ۱۱.۱۰ and ۱۱.۳۰ and the detection limits were ۰.۳۷, ۱.۲۰, and ۱.۳۰ µg L-۱ for copper, manganese, and nickel, respectively. The method presented relative standard deviation as precision were ۲.۲۰%, ۲.۵۰ and ۳.۲۰% for copper, manganese, and nickel, respectively. The accuracy of the new preconcentration procedure was checked by the analysis of the standard reference materials (SRM ۱۵۷۰a Spinach Leaves and SRM ۱۵۱۵ Apple Leaves), and successfully applied to determine Cu۲+, Mn۲+ and Ni۲+ in real water samples with relative recovery values in the range of ۹۵.۰%–۹۹.۰% for the spiked samples.

کلیدواژه ها:

Cloud point extraction ، copper ، manganese ، nickel ، FAAS ، Water