title: Ionic liquid-based zinc oxide nanofluid for vortex assisted liquid liquid microextraction of inorganic mercury in environmental waters prior to cold vapor atomic fluorescence spectroscopic detection.
abstract: Zinc oxide nanofluid (ZnO-NF) based vortex assisted liquid liquid microextraction (ZnO-NF VA-LLME) was developed and employed in extraction of inorganic mercury (Hg(2+)) in environmental water samples, followed by cold vapor atomic fluorescence spectrometry (CV-AFS). Unlike other dispersive liquid liquid microextraction techniques, ZnO-NF VA-LLME is free of volatile organic solvents and dispersive solvent consumption. Analytical signals were obtained without back-extraction from the ZnO-NF phase prior to CV-AFS determination. Some essential parameters of the ZnO-NF VA-LLME and cold vapor generation such as composition and volume of the nanofluid, vortexing time, pH of the sample solution, amount of the chelating agent, ionic strength and matrix interferences have been studied. Under optimal conditions, efficient extraction of 1ng/mL of Hg(2+) in 10mL of sample solution was achieved using 50μL of ZnO-NF. The enrichment factor before dilution, detection limits and limits of quantification of the method were about 190, 0.019 and 0.064ng/mL, respectively. The intra and inter days relative standard deviations (n=8) were found to be 4.6% and 7.8%, respectively, at 1ng/mL spiking level. The accuracy of the current method was also evaluated by the analysis of certified reference materials, and the measured Hg(2+) concentration of GBW08603 (9.6ng/mL) and GBW(E)080392 (8.9ng/mL) agreed well with their certified value (10ng/mL). The method was applied to the analysis of Hg(2+) in effluent, influent, lake and river water samples, with recoveries in the range of 79.8-92.8% and 83.6-106.1% at 1ng/mL and 5ng/mL spiking levels, respectively. Overall, ZnO-NF VA-LLME is fast, simple, cost-effective and environmentally friendly and it can be employed for efficient enrichment of the analyte from various water samples.
authors.affiliation: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P. O. Box 2871, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Meseret
authors.initials: M
authors.lastname: Amde
authors.affiliation: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P. O. Box 2871, Beijing 100085, China; Institute of Environment and Health, Jianghan University, Hubei Province, Wuhan 430056, China. Electronic address: jfliu@rcees.ac.cn.
authors.forename: Jing-Fu
authors.initials: JF
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P. O. Box 2871, Beijing 100085, China.
authors.forename: Zhi-Qiang
authors.initials: ZQ
authors.lastname: Tan
authors.affiliation: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P. O. Box 2871, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Deribachew
authors.initials: D
authors.lastname: Bekana
mesh_terms: D002681:China; D004784:Environmental Monitoring; D052578:Ionic Liquids / Q000737:chemistry; D060106:Lakes / Q000737:chemistry; D059627:Liquid Phase Microextraction; D008628:Mercury / Q000032:analysis*; D053758:Nanoparticles / Q000737:chemistry; D045483:Rivers / Q000737:chemistry; D013050:Spectrometry, Fluorescence; D062065:Wastewater / Q000032:analysis; D014874:Water Pollutants, Chemical / Q000032:analysis*; D015034:Zinc Oxide / Q000737:chemistry
chemical_list: D052578:Ionic Liquids; D008628:Mercury; D062065:Wastewater; D014874:Water Pollutants, Chemical; D015034:Zinc Oxide
keywords: CV-AFS; Environmental waters; Inorganic mercury; LLME; Nanofuid