An efficient ionic liquid-based cloud point extraction to preconcentrate mercury in environmental samples and hair of occupational workers before spectrophotometric detection

Abstract

ABSTRACT. Mercury preconcentration in environmental samples and hair of occupational workers prior to spectrophotometric detection was described using a unique, eco-friendly, and quick ionic liquid-based cloud point extraction method. The discovered method used an ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate with Triton X-114 as an extracting phase in the presence of a new chelating agent 3-(2-hydroxy-5-ethoxycarbonylphen-1-ylazo)-1,2,4-triazole at pH 7.0 to separate mercury and measure the complex spectrophotometrically at wavelength 550 nm. The effects of several analytical factors on extraction performance were investigated. With a correlation coefficient of 0.9997. The calibration graph was linear in the range of 2.0-400 µg/L. The limit of detection and preconcentration factor, respectively, were 0.5 µg/L and 100. The relative standard deviation of 100 and 300 µg/L mercury (n = 10) was 1.5 and 2.2, respectively, indicating the precision and reliability of the new IL-CPE approach. The accuracy of the proposed approach confirmed through the certified reference materials analysis. The applicability of the established technique was demonstrated successfully by the estimation of trace mercury in environmental samples and hair of occupational workers.     KEY WORDS: Mercury, Ionic liquid-based cloud point extraction, Environmental and hair samples, Spectrophotometry   Bull. Chem. Soc. Ethiop. 2022, 36(4), 767-778.                                                         DOI: https://dx.doi.org/10.4314/bcse.v36i4.4