•The deep eutectic solvent (DES) provide as environmentally benign option to organic solvents.•The DES was prepared by mixing zinc chloride with acetamide at different molar ratio.•The DES are also ...regarded as ionic liquids analogues, bio-degredable due to their low vapor pressure.•Low detection limit, high enhancement factor and short extraction time were achieved for green extraction method.
A green and innovative eutectic solvent based extraction method was proposed for the determination of trace level vanadium in water and food samples by graphite furnace atomic absorption spectrometry. In this extraction technique magnetic stirrer was used for preparation of eutectic solvent by mixing of zinc chloride and acetamide at different molar ratios. Extraction capability of eutectic solvent was increased by adding a non ionic surfactant (Triton X-114) to enhanced phase transfer ratio, to significantly increase the recovery of hydrophobic complex of vanadium with ammonium pyrrolidine dithiocarbamate. A multivariate technique was applied to evaluate the important extraction parameters, which plays important role for optimum recovery of the targeted analyte by proposed extraction method. Multivariate techniques such as (factorial design and central composite design) were applied to screening out the most significant extraction parameters and optimized them. Under optimized extraction conditions, limit of detection and enhancement factor were found to be 0.01 µg L−1 and 64.6, respectively. The relative standard deviation for the determination of trace level vanadium at 0.32 µg L−1 concentration, was achieved to be <3.0% (n = 10). Validity and accuracy of the proposed extraction method was checked by analysis of certified reference materials of Canadian lake water and tomato leaves with % age recovery >98%. The eutectic solvent extraction method was successfully applied for the determination of the trace level vanadium in real water samples of different sources and acid digested food samples, collected from different locations of Tokat city, Turkey.
•Vortex assisted based liquid-liquid microextraction (VA-LLME) method was developed for preconcentration of selenium.•The developed VA-LLME method was used first time for selenium determination in ...water, agricultural soil and food samples.•It has an excellent analytical figure of merits such as high EF, low LOD, LOQ and RSD.•Multivariate techniques were used for screening and optimization of the extraction parameters.
A green vortex assisted based liquid-liquid microextraction (VA-LLME) method was developed for preconcentration of selenium. Ammonium pyrrolidine dithiocarbamate (APDC) was used to form a hydrophobic complex with selenium in natural water, agricultural soil and food samples by GFAAS. Whereas Triton X-114, a nonionic surfactant and 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid were used for Se extraction as a dispersing medium. The conical flasks contents were shack on a vortex mixer to increase the extraction efficiency. Multivariate techniques were used to evaluate extraction parameters; pH, vortex time, APDC amount, volume of ionic liquid and Triton X-114 and centrifugation rate on the recovery of Se. The central composite design (CCD) was used for further optimization of the essential extraction parameters. The enhancement factor and limit of detection were obtained as 98.7 and 0.07 µg L−1. The certified reference materials was used for accuracy of method and the related standard deviation was found to be 3.51%. The resulted data indicated that concentrations of Se in all types of water samples were below the permissible limit recommended by WHO.
The polymer, polystyrene polydimethyl siloxane was loaded into the micropipette tip of the syringe system as an adsorbent to developed miniaturized solid phase microextraction. Standard solutions of ...arsenate and arsenite were passed through the adsorbent loaded in micropipette tip to check the adsorption behaviors. It was observed that arsenate adsorbed on the polystyrene polydimethyl siloxane in the pH rang of 6–8, while arsenite was directly passed through the micropipette tip of syringe system. The adsorbed arsenate in micropipette tip of syringe system were eluted by 1.0M hydrochloric acid. The total inorganic arsenic contents were obtained by the addition of oxidizing agent potassium permanganate into the studied samples before passing to the micropipette tip of syringe system. Arsenite concentration in water samples were measured by subtracting arsenate from total inorganic arsenic concentration. Different characteristics which effect the determination of arsenate specie like amount of adsorbent, adsorption capacity, pH, pulled and pushed cycles for adsorption and desorption, volume of sample, eluent type and it volume were also studied in detail. Enrichment factor and detection limit of arsenate by desired method were 218 and 6.9ngL−1 respectively. The relative standard deviation was 4.1% (n=10, C=0.12µgL−1). Accuracy of the desired technique was confirmed by analysis of the CRMs (Lake Ontario Water TM-28.3 and Riverine Water NRCC-SLRS-4). Desired technique was significantly useful for determination of the total arsenic, arsenate, and arsenite contents in different natural water samples.
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•Miniaturized solid phase microextraction was developed by using micropipette tip of the syringe system.•Polystyrene polydimethyl siloxane was first time used as an adsorbent for inorganic arsenic specition and analysed by ET-AAS.•Simple, rapid, low cost and green extraction method was developed.•It was applied for determination of total As, arsenate and arsenite in real water samples from different location.•The aim of this work is to introduce an innovative green preconcentration approach.
An innovative deep eutectic solvent with ultrasound-assisted based dispersive liquid-liquid microextraction method was first time develop for separation and preconcentration of trivalent chromium in ...environmental water samples. The `deep eutectic solvent with ultrasound-assisted based dispersive liquid-liquid microextraction method was prepared from acetamide and zinc chloride at different molar ratio. The complexing agent calmagite was used for complex formation with trivalent chromium in the range of 8.0–10 optimum pH values. After that complex of trivalent chromium with calmagite was entrap by using deep eutectic solvent. Extraction efficiency was increase by adding tetrahydrofuran into the extraction unit. Extracted and pre-concentrated trivalent chromium contents from water determined by using graphite furnace atomic absorption spectrometry. Effected extraction efficiency parameters are pH, concentration of calmagite, volume of deep eutectic solvent, volume of tetrahydrofuran, molar ratio of the deep eutectic solvent and extraction time were optimized. The deep eutectic solvent with ultrasound-assisted based dispersive liquid-liquid microextraction method has excellent analytical figure of merits such as enrichment factor and limit of detection 85.1 and 6.0 ng L−1, respectively. Accuracy of the developed method was checked by the certified reference materials of water (TM-28.3) with percentage recovery >98%. The proposed method was successfully applied for determination of trivalent chromium in different natural water samples.
•An inventic DES-UA-DLLME method was developed for chromium extraction.•The calmagite was used for complex formation with chromium.•DES was formed by zinc chloride with acetamide at 1:2 M ratio.•DES-UA-DLLME method was applied to chromium in water samples by GFAAS.•Low detection limit and short extraction time were observed.
It was investigated that toxic metals (cadmium and lead) enhanced in coal gangue soil used for the reclamation of soil, creates adverse impacts on atmosphere. Presently the chemical fractionation of ...toxic metals in coal, inner and outer coal gangue soil samples of Lakhra coalfield were studied along with the impact on the orchard grass grown on coal gangue soil in a subside land of the coal mining area. The BCR sequential extraction scheme (BCR-SES) was carried out to determine the different chemical profiles of heavy metals in coal and coal gangue soil samples. For comparative purpose time saving conventional single step extraction (CSE) and vortex assisted single step extraction (VSE) schemes based on same working setting used BCR extraction scheme. The all three procedures were validated by a certified soil sample (BCR 483) and standard addition method in real samples. The total Cd and Pb in coal, soil and grass samples were determined prior to oxidize by acid mixture. The separation of each fraction of Cd, and Pb in all types of environmental samples by VSE could be completed in 30–120 s. The extracted Cd and Pb concentrations in reducible fractions by CSE and VSE extraction procedure were 2.5–5% higher than those values gained through BCR-SES. About 71 and 50% of Cd and Pb in coal samples were observed in acid soluble, reducible and oxidizable fraction, respectively, whilst rest of Cd and Pb (29 and 50%) were found in residual phase. The orchard grass (Dactylis glomerata) grown on land reclaimed with OSG was analysed, the bioaccumulate Cd and Pb may create adverse impacts on grazing cattle.
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•The coal mining activities enhance the toxic metals contamination in gangue soil reclamation.•The mining and burning of lakhra coal created adverse impacts on environments and aquatic system.•The efficiency of conventional sequential extraction is enhanced by single step extraction.•The soil samples of outside the mining area have enriched values of Cd and Pb in reducible and oxidizable fractions.•Translocation of Cd from root to shoot indicated the orchard grass be used in phyto-extraction.
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•Simultaneously evaluated the contamination of F− and arsenic in surface water.•Total and bio-available F− and arsenic in soil.•F− and arsenic contents in grain crops and their ...bio-concentration factor.•Estimated daily intake and risk assessment of F− and arsenic in different age groups.
The aim of present study was to simultaneously estimate the arsenic (As) and fluoride (F−) concentrations in irrigated surface water, soil and grain crops of Nagarparkar, Pakistan during 2010–2012. The As and F− were analyzed by hydride generation atomic absorption spectrometer and ion selective electrode, respectively. Total arsenic (AsT) and F− in irrigated surface water samples were found in the range of 360–683μgL−1 and 18.5–35.4mgL−1, respectively. While AsT and F− concentrations in agriculture soil samples were observed in the range of 110–266 and 125–566mgkg−1, respectively. The water extractable As and F− were found 3–4% of total concentration of these in soils.
The AsT concentration was higher in kidney been (KB) as compared to pearl millet (PM) and green gram (GG), whereas GG had higher F− levels as compared to other two grain crops (p<0.05). The KB samples grown in nine sites shows BCF of As in the range of 0.018–0.038. The GG has higher BCF of F− as compared to KB and PM (p<0.05) grown in all sites. The exposure dose and risk factor of As and F− were obtained by estimated daily intake (EDI) and hazardous index (HI). It was found that all understudy age groups were at the severe risk of arsenicosis and fluorosis, but the severity is higher in younger age group (7–15years) as compared to elder groups (p<0.05).
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•Ultrasound energy enhance the extraction efficiency of Pb as compared to thermostatic shaking.•To overcome the adverse effects of IL on analysis, back extraction of analyte in ...aqueous phase done.•The incubation and shaking for optimum extraction efficiency of Pb was achieved in 80s using US bath.•The extraction recovery of Pb was up to 2% less, on shaking in thermostatic electrical shaker than US bath.•The Pb levels in real ground and stored rain water samples of an endemic region was>WHO limit.
An efficient preconcentration technique based on ultrasonic-assisted ionic liquid-based dual microextraction (UA-ILDµE) method has been developed to preconcentrate the lead (Pb+2) in ground and stored rain water. In the current proposed method, Pb+2 was complexed with a chelating agent (dithizone), whereas an ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate) was used for extraction purpose. The ultrasonic irradiation and electrical shaking system were applied to enhance the dispersion and extraction of Pb+2 complex in aqueous samples. For second phase, dual microextraction (DµE phase), the enriched Pb+2 complex in ionic liquid, extracted back into the acidic aqueous solution and finally determined by flame atomic absorption spectrometry. Some major analytical parameters that influenced the extraction efficiency of developed method, such as pH, concentration of ligand, volume of ionic liquid and samples, time of shaking in thermostatic electrical shaker and ultrasonic bath, effect of back extracting HNO3 volume, matrix effect, centrifugation time and rate were optimized. At the sample volume of 25mL, the calculated preconcentration factor was 62.2. The limit of detection of proposed procedure for Pb+2 ions was found to be 0.54μgL−1. The validation of developed method was performed by the analysis of certified sample of water SRM 1643e and standard addition method in a real water sample. The extraction recovery of Pb+2 was enhanced≥2% with shaking time of 80s in ultrasonic bath as compared to used thermostatic electrical shaker, where for optimum recovery up to 10min was required. The developed procedure was successfully used for the enrichment of Pb+2 in ground and stored rain water (surface water) samples of an endemic region of Pakistan. The resulted data indicated that the ground water samples were highly contaminated with Pb+2, while some of the surface water samples were also have higher values of Pb+2 than permissible limit of WHO. The concentration of Pb+2 in surface and ground water samples was found in the range of 17.5–24.5 and 25.6–99.1μgL−1 respectively.
A simple and green preconcentration method of hydrophobic to hydrophilic switchable liquid-solid dispersive microextraction (HSL-SDM) has been first time introduced as separation method for arsenic ...ion in real water samples. Multiwall carbon nanotube (MWCNT) was immobilized with diethylenetriamine (DETA) and then used as solid phase adsorbent for the determination of trace level of arsenic ion by HSL-SDM method prior to analysis by hydride generation atomic absorption spectrometry. Reversibly hydrophobic-hydrophilic switchable of functionalized MWCNT can occur due to the exposing of carbon dioxide (CO
2
) as anti-solvent trigger. The reversibly hydrophobic-hydrophilic switchable phenomena of immobilized MWCNT in the liquid-solid dispersive microextraction were checked by using FT-IR and SEM. The optimized analytical condition for arsenic ion analysis such as enrichment factor and limits of detection were obtained 83 and 3.05 ng L
−1
, respectively. Accuracy of the developed HSL-SDM method was confirmed by the analysis of certified reference materials. Our developed HSL-SDM method was successfully applicable for measurements of arsenic ions in real water samples.
Supramolecular solvent-based dispersive liquid-liquid microextraction was used as a preconcentration method for the determination of trace levels of Hg. This simple method accurately measured ...oxidized HgII content in claystone and sandstone samples obtained from the Thar Coalfield in Pakistan. Cold vapor atomic absorption spectrometry was used as the detection technique because it is reliable and accurate. The HgII in acidic media forms a complex with dithizone (DTz) in the presence of supramolecular solvent (tetrahydrofuran and 1-undecanol), forming reverse micelles. Formation of the Hg-DTz complex was achieved to increase the interactions with the supramolecular solvent phase at pH 2.5 under the optimized experimental conditions. After addition of the supramolecular solvent to the aqueous solution, the micelles were uniformly mixed using a vortex mixer. The cloudy solution was centrifuged, and the Hg-DTz complex was extracted into the supramolecular solvent phase. Under optimized experimental conditions, the LOD and enrichment factor were found to be 5.61 ng/L and 77.8, respectively. Accuracy of the developed method was checked with Certified Reference Materials. The developed method was successfully applied for the determination of HgII in claystone and sandstone samples from the Block VII and Block VIII areas of the Thar Coalfield on the basis of depth.
In the current study, we have developed a green water switchable liquid–liquid microextraction method for separation, preconcentration, and estimation of selenium concentration in the real samples. ...First time introducing the water switchable liquid–liquid microextraction method to determine the trace level selenium in different food and soft drink samples. Water switchable medium was formed by the reaction of diethylenetriamine base when exposed to uniformed pressure of carbon dioxide. After being exposed to carbon dioxide, water switchable medium reversibly exchanges in two separated aqueous and organic phases. Advantages of carbon dioxide uses are cheap, environmental friendly, non-accumulation, removable, and require the opaque materials for operating container. Water switchable phenomena occurred easily from low polarity to high polarity organic solvent. Experimental variables of the water switchable liquid–liquid microextraction (LLME) method were optimized into its optimum values such as pressure, pH, centrifugation speed, extraction time, and concentration of complexing agent. The certified reference material of Canada Lake Water (TMDA-53.3) and CS-M-3 Mushroom (
Boletus edulis
) was used for validation of the present water switchable LLME method. Enhancement factor and limit of detection were obtained 85.5 and 0.018 μg kg
−1
, respectively. Developed green water switchable LLME method was successfully applied for assessment of total selenium in tomato, pumpkin seed, mushroom, garlic, rice, pistachio, chickpea, hazelnut, walnut, apple juice, and ice tea samples.
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