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

a b s t r a c tZinc 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 þ ) 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 1 ng/mL of Hg 2 þ in 10 mL of sample solution was achieved using 50 μL of ZnO-NF. The enrichment factor before dilution, detection limits and limits of quantification of the method were about 190, 0.019 and 0.064 ng/mL, respectively. The intra and inter days relative standard deviations (n¼8) were found to be 4.6% and 7.8%, respectively, at 1 ng/mL spiking level. The accuracy of the current method was also evaluated by the analysis of certified reference materials, and the measured Hg 2 þ concentration of GBW08603 (9.6 ng/mL) and GBW(E)080392 (8.9 ng/mL) agreed well with their certified value (10 ng/mL). The method was applied to the analysis of Hg 2 þ in effluent, influent, lake and river water samples, with recoveries in the range of 79.8-92.8% and 83.6-106.1% at 1 ng/mL and 5 ng/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.

Transformation and bioavailability of metal oxide nanoparticles in aquatic and terrestrial environments. A review

“…fuel cells, plastics, consumer products) (Devener and Anderson, 2006;Lagaron and Lopez-Rubio, 2011;Lee et al, 2010;Mu and Sprando, 2010), environmental application (e.g. environmental analysis, sensing, remediation, amendments) (Amde et al, 2016(Amde et al, , 2015Bai and Zhou, 2014;Corr, 2013;Gan et al, 2016;Ghasemi et al, 2017;Ju-Nam and Lead, 2016;Lee et al, 2016;Mahdavi et al, 2014;Mirzaei et al, 2016;Parga et al, 2012;Park et al, 2016;Rahman et al, 2017;Singhal et al, 2017;Trujillo-Reyes et al, 2014;Vuong et al, 2016), sustainable chemistry (e.g. catalysis) (Almukhlifi and Burns, 2016;Gawande et al, 2016;Montini et al, 2016;Navalon et al, 2016;Peng et al, 2016), and health (e.g.…”

Methods and recent advances in speciation analysis of mercury chemical species in environmental samples: a review

“…Since the concentration of Hg in environmental samples might be at trace level, the Hg speciation analysis requires the sample pre-treatment and pre-concentration methods such as SPE, [8] SPME, [9] HF-LLLME, [10,11] DLLME, [12][13][14][15][16] SDME, [17,18] CPE, [19] and P&T. [20][21][22][23] Separation and determination techniques including LC, GC, and CE coupled to ICP-MS, [3,10,12,[24][25][26] PJD-AFS, [27] AFS (HG/CV-AFS), [9,28] and CV-AAS [9] have been used. As well, particular attention has to be paid to the sampling, transportation, and proper sample storage procedures.…”

“…[12,14,44,56] In DLLME, application of dispersive solvent, usually which dissolve in both sample and extraction solvent, have been practiced for complete transfer of the target analytes between the two phases which can be stated as one of its drawbacks since solvent consumption should be minimized in analysis from environmental point of view and it also decreases the distribution ratio from analytical perspective. [57] To avoid this, other processes like ultrasonication [58,59] and vortexing [15,16,59] can be used for effective agitation of the mixtures. For high enrichment of the analytes, chelating agents like sodium diethyldithiocarbamate, [12] APDC, [16] dithizone, [44,56] 1-(2-pyridylazo)-2-naphthol and L-cysteine [14] have LPME • DLLME • SDME • VA-LLME • HF-LPME SPE/SPME…”

“…[57] To avoid this, other processes like ultrasonication [58,59] and vortexing [15,16,59] can be used for effective agitation of the mixtures. For high enrichment of the analytes, chelating agents like sodium diethyldithiocarbamate, [12] APDC, [16] dithizone, [44,56] 1-(2-pyridylazo)-2-naphthol and L-cysteine [14] have LPME • DLLME • SDME • VA-LLME • HF-LPME SPE/SPME…”

“…[16] Even though Hg 2+ was considered as the only target analyte, it is "green" technique (no dispersive solvent and nontoxic extraction solvent was used), fast, simple, sensitive (LOD, 0.019 ng/mL) and compatible with AFS detection. VA-LLME have been also used in the speciation analysis of Hg 2+ , MeHg, and EtHg in sediment samples using dithizone and [HMIM] [PF 6 ] as chelating and extraction solvents, respectively.…”