Surface active ionic liquid‑assisted cloud point extraction method for preconcentration of nickel in environmental samples before its FAAS determination

Abstract

Green, rapid and modified surface-active ionic liquid assisted cloud point extraction method (SAIL-CPE) was developed to preconcentrate trace levels of nickel Ni(II) ions in environmental samples perior to its detection by FAAS. The proposed method based on utilizing a mixture of a nonionic surfactant (Triton X-114) and a surface-active ionic liquid, 1-hexadecyl-3-methylimidazolium chloride (C16MeImCl), as an extracting phase for Ni(II) ions after the complexation with sunset yellow FCF at pH 6.5. The impact of different analytical parameters on improving the extraction efficiency was invistigated. In the range of 2.0-600 µg L−1, the calibration graph was linear with correlation coefficient of 0.9998. Limit of detection and preconcentration factor were 0.6 and 100. The reliability and precision of the proposed SAIL-CPE system as the relative standard deviation (RSD %) in the presence and absence of SAIL were examined by applying ten replicate determinations of 300 µg L-1 of Ni(II), and RSD % of the recoveries were found to be 1.40 and 2.9%, respectively. The validation of the proposed procedure was verified by test of certified reference materials (TMDA-51.3 fortified water, TMDA-53.3 fortified water and SRM spinach leaves 1570A) applying the standard addition method. Finally, the proposed SAIL-CPE method was developed and applied to preconcentrate and determine of trace levels of Ni(II) ions in real water, food and tobacco samples with satisfactory results.