Volume Of Ionic Liquid Research Articles

Aqueous two-phase extraction technique based on magnetic ionic liquid-nonionicsurfactant for phenolic acids in grape, apple, pear, and banana

An aqueous two-phase extraction system was constituted using magnetic ionic liquid-nonionic surfactant for phenolic acids and the developed method was applied to apple, grape, pear, and banana samples. Ionic liquids based on imidazolium containing butyl, allyl, and benzyl groups were used for extraction. The parameters influencing the extraction efficiency such as volume of ionic liquids, type and amount of surfactant and salt, ultrasound extraction time, temperature, and sample pH were optimized. The extraction efficiencies of ionic liquids were compared for phenolic acids under optimized conditions. Limits of detection and limits of quantification were in the range of 1.34-1.56 μg L$^{-1\, }$and 4.33-4.68 μg L$^{-1}$, respectively. The interday and intraday precision (RSD%) for the phenolic acids at 5 and 25 μg L$^{-1\, }$were in the range of 4.48%-5.69% and 3.02%-4.51%, respectively. The spiked recoveries of phenolic acids were between 70.78% and 99.97% in real samples.

Moving municipal WWTP towards circular economy: Cellulose recovery from primary sludge with ionic liquid

Tetrakis (hydroxymethyl) phosponium chloride ionic liquid was evaluated to recover carbohydrates, especially cellulose, from municipal wastewater treatment plant (WWTP) primary sludge (96 % water content). Different process operative conditions were evaluated: temperature (35, 60 and 80 ℃), time (6, 13 and 20 h) and sludge weight:ionic liquid volume ratio (1 g TS of SLUDGE: 7, 12 and 17 mL). A three levels, three factors central design was applied to optimize the procedure of recovery of the cellulose. Precipitated solids were analysed to quantify the content of cellulose, hemicellulose, lignin, proteins and ashes. The ionic liquid showed good performances in the recovery of cellulose. The average amount of carbohydrates recovered using the ionic liquid method was comparable with the amount of carbohydrates measured by the Dubois method in the raw sludge. All cellulose was recovered in the precipitated solid, but also part of the protein and ashes. According to the statistical tests, two interactions were found: between temperature and sludge:IL ratio for recovery of hemicellulose; between temperature and time for recovery of proteins. Experimental design was not useful to find optimized conditions of the process. Experiments realised with central values (60 °C; 13 h; 1:12 mL) gave very good results, allowing the recovery of high quantities of cellulose with the best removal of ashes but maintaining high quantities of proteins in the precipitate. For these reasons central values can be considered optimal reaction conditions. The design of novel ionic liquids will be necessary to fully purify the cellulose in a single dissolution step.

An In Situ Dansylation Ultrasound-Assisted Dispersive Liquid-Liquid Microextraction Based on Ionic Liquid for Determination of Biogenic Amines in Foods

An in situ derivatization combined with ionic liquid-based ultrasound-assisted dispersive liquid-liquid microextraction (IL-USADLLME) method was developed for the extraction of seven biogenic amines (BAs) namely putrescine, cadaverine, histamine, tryptamine, tyramine, spermidine, and spermine in foods. BAs were derivatized in situ with dansyl chloride and 1-butyl-3-methylimidazolium hexafluorophosphate, [C4MIM][PF6] (extraction solvent) was dispersed into the aqueous sample solution as fine droplets by ultrasonication. Acetonitrile was used as a disperser solvent. Factors affecting the extraction efficiency, such as the dansylation conditions, volume of ionic liquid, ultrasonication time, and extraction temperature have been optimized. BAs were analyzed using C18 monolithic column of high performance liquid chromatography coupled with diode array detector after the extraction and centrifugation. The proposed method was linear over 1–100 mg/L with a correlation coefficient of 0.9871–0.9992. The limit of detection and quantification based on signal to noise ratio of 3 and 10 ranges from 0.06 to 0.3 mg/L and 0.19 to 0.99 mg/L, respectively. The relative standard deviations (RSDs) for intra-day and inter-day assay were less than 3.6%. Relative recoveries ranging from 70.7-118.4% were established using mango juice, local delicacies (tempe, budu), and canned sardine fish samples with %RSD less than 5.5%. The developed method was eco-friendly and was found to be sensitive, rapid, and cost-effective for the determination of BAs in a wide range of food sample matrices.

In Situ Formation of Ionic Liquid by Metathesis Reaction for the Rapid Removal of Bisphenol A from Aqueous Solutions

In this work we present a rapid and easy method to remove the totality of bisphenol A from aqueous solutions using ionic liquid (IL). Dispersive liquid–liquid microextraction is employed. The IL 1-octyl-3-methylimidazolium bis((trifluoromethane)sulfonyl)imide ([C8C1im] [NTf2]) is formed in situ because of the mixture of 1-octyl-3-methylimidazolium chloride ([C8C1im]Cl) and lithium bis(trifluoromethanesulfonyl)imide (Li[NTf2]) aqueous solutions. A cloud of microdroplets of IL formed by the dispersion generated through the precursors metathesis reaction allows the rapid and total extraction of bisphenol A (BPA). After centrifugation, the formed IL phase is deposited at the bottom of the flask and the total amount of BPA is extracted in the sedimented phase. The volume of IL is very low, in the order of microliters, which enables us to remove all the BPA from the solution. The technique studied is highly efficient, cost-effective, and presents less environmental impact than other extraction techniques, thus becoming an outstanding alternative to the most commonly used methods. BPA concentration is determined by high performance liquid chromatography by injecting the IL phase directly. An extraction kinetic model for the kinetic profile has been tested for this method, which allows to infer the ideal experimental conditions to execute the extraction method.

Microwave-assisted ionic liquid microextraction combined with high performance liquid chromatography for the determination of naphthoquinones from Arnebia euchroma (Royle) Johnst

A simple, rapid, and green microwave-assisted ionic liquid microextraction was established and applied to the extraction of naphthoquinones in Arnebia euchroma (Royle) Johnst., including shikonin, acetylshikonin, and β,β′-dimethylacrylshikonin. In this study, 100 μL of 1-hexyl-3-methylimidazolium hexafluorophosphate ([C6mim][PF6]) was used as extraction solvent. After the sample powder and ionic liquid were mixed homogeneously by the vortex, microwave extraction was performed. The sample extract was diluted with methanol and then filtered. Finally, the resulting solution was separated and determined by high performance liquid chromatography-diode array detection. In this work, the experimental parameters affecting the extraction yields, including size of sample particle, sample amount, type and volume of ionic liquid, microwave power, and time were optimized. The experimental results showed that the compounds have a good linear relationship (r > 0.9999). The limits of detection and quantification were 5.0–19.2 ng mL−1 and 16.7–63.9 ng mL−1. The spiked recoveries were between 76.95% and 93.55%. The intra-day and inter-day precision were lower than 3.14% and 8.53%, respectively. Compared with ultrasound-assisted extraction and soxhlet extraction, the present method consumed less sample, extraction solvent, and extraction time. So, the present method can be used for the extraction and determination of naphthoquinones in Chinese herbal medicine.

An environmental friendly enrichment method for microextraction of cadmium and lead in groundwater samples: Impact on biological sample of children

A novel ionic liquid-based vortex assisted dispersive liquid–liquid micro extraction procedure(IL-VADLLμE) was proposed for the enrichment of toxic metals, cadmium (Cd) and lead (Pb) in different types of water samples, domestic treated and groundwater (tube well and hand pump). Whereas, the concentration of both toxic metals was also determined in the scalp hair of children (age ranged 1–3 years), drinking contaminated groundwater termed as exposed group, whereas for comparative purposes scalp hair of age matched children consumed domestically treated water, named as non-exposed group. To preconcentrate the trace levels of Cd and Pb, a green chelating agent, l-cysteine (2-amino-3-sulfhydrylpropanoic acid) was used for complexation, an ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM] [PF6] utilized as extractant and hexafluorophosphate ion (PF6−) as anion pairing agent, which facilitate the enrichment of hydrophobic complexes of analytes into the acceptor phase. Various operative features for the IL-VADLLμE method like pH of standards/samples, volume of ionic liquid and sample solution, concentration of ligand, ion pair reagent and ionic liquid, vortex and electrical shaking time (for comparative purpose), were thoroughly optimized. The projected method was effectively applicable to assess the Cd and Pb in trace level in real water sample (surface and groundwater) and scalp hair samples of children belongs to exposed and non-exposed areas. The high contents of both toxic metals in scalp hair samples of children consuming groundwater indicate that the adverse impacts of both toxic metals especially Pb on the general health as well as neuron and skeletal problem, from child hood.

Alkolsüz İçecekler ve Gıda Ürünlerinde Tartrazinin Özütlenmesi için Basit ve Ucuz Ultrason Destekli Mikroekstraksiyon Prosedürü

In this study, a simple and cheap ultrasound-assisted ionic liquid-based floating organic droplets microextraction (UA-IL-FODME) has been proposed for spectrophotometric determination of synthetic food dye (tartrazine) in soft drinks and food samples. 1-Octyl-3-methylimidazolium tetrafluoroborate [C8MIM][BF4] and 1-octanol were used as the extraction solvent and dispersant solvent, respectively. The method is based on extracting the tarrazine to the ionic phase with the help of ultrasonic effect at pH 5.5. Some experimental variables (pH, ionic liquid amount, type and volume of dispersive solvent, and ultrasonic conditions) were studied and optimized in detail. In optimum conditions, some analytical parameters of the method were as follows. Operating range, limit of detection, preconcentration factor, recovery % and RSD % values were 10-700 µg L-1, 3.2 µg L-1, 75, 94.7-104.7% and 2.7%, respectively. Following comprehensive validation studies, the recommended method was successfully applied to the extravasation and determination of tartrazine in soft drinks and foodstuff.

A Reliable Database for Ionic Volume and Surface: Its Application To Predict Molar Volume and Density of Ionic Liquid

The ionic volume and surface area of the anion and cation are very important and fundamental properties of ionic liquids (ILs) which are widely used to predict the properties of IL systems. In this study, ionic volumes and surface areas for 249 ions were calculated, and thus, a database was established. Based on the database, two prediction models (each containing only one correction coefficient) for the molar volume of 126 ILs were developed using COSMO and van der Waals volumes. In addition, the densities of the 126 ILs were calculated by using the equation ρ = M/V. The average absolute relative deviations of the predicted molar volume and density models were less than 3.5%, indicating the excellent precision of our models. Therefore, it can be concluded that the ionic volume and surface area database established in this work was reliable and could be extended to predict physicochemical properties of more than 10,000 ILs.

Simultaneous Extraction and Determination of Compounds With Different Polarities From Platycladi Cacumen by AQ C18-Based Vortex-Homogenized Matrix Solid-Phase Dispersion With Ionic Liquid.

This study presented a rapid, simple and environmentally friendly method of employing AQ C18-based vortex-homogenized matrix solid-phase dispersion with ionic liquid (AQ C18-IL-VHMSPD) for the extraction of compounds with different polarities from Platycladi Cacumen (PC) samples by ultra high-performance liquid chromatography with PDA detection. AQ C18 (aqua C18) and ionic liquid ([Bmim]BF4) were used as the adsorbent and green elution reagent in vortex-homogenized MSPD procedure. The AQ C18-IL-VHMSPD conditions were optimized by studying several experimental parameters including the type of ionic liquid, the type of adsorbent, ratio of sample to adsorbent, the concentration and volume of ionic liquid, grinding time and vortex time. The recoveries of the target compounds were in the range of 96.9–104% with relative standard deviation values no more than 2.8%. The limits of detection and limits of quantitation were in the range of 0.2–1.2 and 1.0–5.4 ng mL-1, respectively. Compared with the traditional ultrasonic-assisted extraction, the developed AQ C18-IL-VHMSPD method required less sample, reagent and time. It was concluded that the AQ C18-IL-VHMSPD method was a powerful method for the extraction and quantification of the high polarity and low polarity compounds in traditional Chinese medicines samples.

Solvent Bar Micro-Extraction of Heavy Metals from Natural Water Samples Using 3-Hydroxy-2-Naphthoate-Based Ionic Liquids

Developments in the liquid micro-extraction of trace metals from aqueous phases have proven to be limited when extended from pure water to more complex and demanding matrices such as sea water or wastewater treatment effluents. To establish a system that works under such matrices, we successfully tested three task-specific ionic liquids, namely trihexyltetradecyl- phosphonium-, methyltrioctylphosphonium- and methyltrioctylammonium 3-hydroxy-2-naphthoate in two-phase solvent bar micro-extraction (SBME) experiments. We describe the influence of pH, organic additives, time, stirring rate and volume of ionic liquid for multi-elemental micro-extraction of Cu, Ag, Cd and Pb from various synthetic and natural aqueous feed solutions. Highest extraction for all metals was achieved at pH 8.0. Minimal leaching of the ionic liquids into the aqueous phase was demonstrated, with values < 30 mg L−1 DOC in all cases. Sample salinities of up to 60 g L−1 NaCl had a positive effect on the extraction of Cd, possibly due to an efficient extraction mechanism of the present chlorido complexes. In metal-spiked natural feed solutions, the selected SBME setups showed unchanged stability under all conditions tested. We could efficiently (≥85%) extract Cu and Ag from drinking water and achieved high efficacies for Ag and Cd from natural sea water and hypersaline water, respectively. The method presented here proves to be a useful tool for an efficient SBME of heavy metals from natural waters without the need to pretreat or modify the sample.

Optimization of lanthanum transport through supported liquid membranes based on ionic liquid

Various methodologies have been proposed to selectively separate lanthanides. Nevertheless, the researches of more sustainable and effective methods are sought after motivated by economical and environmental concerns. We extracted and stripped the trivalent lanthanum (La(III)) in one step using a supported liquid membrane (SLM). The system was prepared by immobilization of the carrier–ionic liquid mixture (tributyl phosphate (TBP) and 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl) imide ([C4mim] [Tf2N])) into the hydrophobic polyvinylidene fluoride film (PVDF) and it was placed between two independent compartments of glass diffusion cell. Stripping phase was chosen as distilled water. The lanthanum transport efficiency was optimized by two level three factor full factorial design. Optimum conditions for lanthanum transport were identified as150mg/L initial La(III) concentration, 1:1 carrier–ionic liquid volume ratio and pH 5. In these conditions 38.15±0.16% transport was achieved and pH found the most effective factor on La(III) transport in specified factor range values. Repeated runs were conducted to determine stability of membrane. Membrane characterization was carried out by means of environmental scanning electron microscopy (SEM). Membrane filter’s permeability for optimum La(III) concentration was calculated as 7.30×10−10cm2s−1. As a result, lanthanum transport has been carried out by supported liquid membrane method, which has more practical character and contains green chemistry components.

Ionic liquid-based salt-induced liquid-liquid extraction of polyphenols and anthraquinones in Polygonum cuspidatum

Ionic liquid-based salt-induced liquid-liquid extraction was developed for the first time and applied to the extraction of four active constituents, including polydatin, resveratrol, emodin, and physcion in Polygonum cuspidatum (P. cuspidatum). In this study, ionic liquid was used as extraction solvent. The dried P. cuspidatum samples purchased from the pharmacy were triturated and passed through a 120-mesh sieve. The obtained sample powders were dried to constant weight at 55 ℃, and then mixed with extraction solvent. The extraction was carried out with the aid of ultrasound. Three phases, including ionic liquid-rich, salt-rich and solid sample phases were formed in the presence of salt. The target analytes were enriched in ionic liquid phase and then determined by high performance liquid chromatography. The experimental parameters, such as type and volume of ionic liquid, type and amount of salt, pH value of extraction medium, ultrasound power, ultrasound time and centrifugal condition, were optimized. The calibration curves showed good linear relationship (r > 0.9994). The limits of detection and quantification were in the range of 2.8–29.5 and 9.4–98.3 ng mL−1, respectively. The spiked recoveries were between 92.16% and 105.41%. Compared with hot reflux extraction and ultrasound-assisted extraction, the proposed method requires less extraction solvent and time. The present method can be applied to the determination of polyphenols and anthraquinones in P. cuspidatum.

Isolation of C-phycocyanin from Spirulina platensis microalga using Ionic liquid based aqueous two-phase system

An aqueous two-phase system (ATPS) with ionic liquids (ILs) was used for the isolate of C-phycocyanin (CPC) from Spirulina platensis microalga. Various imidazolium ILs and potassium salts were studied. The effect of ILs-ATPS on the extraction efficiency of CPC was also studied. The experimental parameters like pH, loading volume, algae concentration, temperature, and alkyl chain length of IL were well-covered in this report. The experimental results showed that the extraction efficiency, the partition coefficient, and the separation factor for CPC were 99%, 36.6, and 5.8, respectively, for an optimal pH value of 7 and a temperature of 308 K. The order of extraction efficiency for CPC using IL-ATPS was: 1-octyl-3-methylimidazolium bromide (C8MIM-Br) > 1-hexyl-3-methylimidazolium bromide (C6MIM-Br) > 1-butyl-3-methylimidazolium bromide (C4MIM-Br). The isolation process followed the pseudo second-order kinetic model and the thermodynamic results were obviously spontaneous.

Determination of Polycyclic Aromatic Hydrocarbons in Tobacco Smoke by Ionic Liquid Enrichment and Gas Chromatography – Mass Spectrometry

ABSTRACTA rapid, efficient and environmentally friendly method based on the ionic liquid (IL) 1-hexyl-3-methylimidazolium hexafluorophosphate ([C6MIM][PF6]) was developed for the determination of 16 polycyclic aromatic hydrocarbons (PAHs) in mainstream tobacco smoke. This technique combined ionic liquid (IL) enrichment with solvent reverse extraction for the replacement of solid phase extraction and rotary evaporation in the traditional method and enriched PAHs in the organic solvent. Several parameters, including the type of ionic liquid, volume of ionic liquid and water, extraction time, vortex time and reverse extraction time, were optimized. After pretreatment, the analytes were analyzed by gas chromatography-mass spectrometry (GC-MS) using selective ion monitoring (SIM). Satisfactory results were achieved when this method was applied to determine PAHs in mainstream tobacco smoke. The calibration curves were linear with correlation coefficients ranging from 0.9955 to 0.9999 at concentration levels of 10–800 µg L−1, and the relative standard deviations of the optimized method were between 0.7% and 5.3%. The limits of detection were 0.01–0.6 ng cig−1, and the recoveries of the compounds were 80.2–118%. A comparison of this protocol with literature methods demonstrated that the proposed procedure provides accurate and reliable sample-treatment for the determination of PAHs in tobacco samples.

Experimental Densities and Calculated Fractional Free Volumes of Ionic Liquids with Tri- and Tetra-substituted Imidazolium Cations

Although it has been estimated that there are at least 1 million ionic liquids (ILs) that are accessible using commercially available starting materials, a great portion of the ILs that have been experimentally synthesized, characterized, and studied in a variety of applications are built around the relatively simple 1-n-alkyl-3-methylimidazolium ([Cnmim]) cation motif. Yet, there is no fundamental limitation or reason as to why tri- or tetra-functionalized imidazolium cations have received far less attention. Scant physical property data exist for just a few trifunctionalized imidazolium-based ILs and there is virtually no data on tetra-functionalized ILs. Thus, there are a broad experimental spaces on the “map” of ILs that are largely unexplored. We have sought to make an initial expedition into these “uncharted waters” and have synthesized imidazolium-based ILs with one more functional group(s) at the C(2), C(4), and/or C(5) positions of the imidazolium ring (as well as N(1) and N(3)). This manuscript ...

Influence of binary solvent system on the stability and efficiency of liquid dye sensitized solar cells

Herein we report the stability of liquid-state dye sensitized solar cell (DSSC) with binary solvent system in electrolyte, targeting to combine the advantages of both solvents for the development of highly stable DSSC device without significant loss of device performance. The binary solvent system was prepared from a mixture of acetonitrile and ionic liquid (IL) 1-butyl-3-methylimidazolium bromide with various IL volume ratios. The current-voltage characteristics of the resulting devices revealed variation of the power conversion efficiency (PCE) with the proportion of IL in the electrolytes. Short current density and conversion efficiency dropped while voltage and fill factor generally increased as the amount of ionic liquid increased. The variation pattern in terms of photovoltaic characteristics and charge transfer impedances is consistent with the changes of IL ratio in all devices. The devices were also inspected for more than 46 days/1100 h in open air at room temperature. Those devices containing ionic liquid demonstrated excellent stabilities compared to devices with pure acetonitrile without considerable loss of PCE. Especially those devices with more than 30% ionic liquid retained over 85% efficiency after 46 days, suggesting a promising prospect for commercialization of DSSCs.

Extraction and Determination of Two Antidepressant Drugs in Human Plasma by Dispersive Liquid–Liquid Microextraction‒HPLC

In this study, an effective method of ultrasound-assisted ionic liquid based dispersive liquid–liquid microextraction (UA−IL−DLLME) coupled with HPLC was applied for extraction and determination of two antidepressant drugs: venlafaxine hydrochloride and amitriptyline hydrochloride from human plasma samples. Three ionic liquids were studied: 1-butyl-3-methyl imidazolium hexafluorophosphate, 1-hexyl-3- methyl imidazolium hexa-fluoro-phosphate, and 1-octyl-3-methyl imidazolium hexafluorophosphate [C8MIM][PF6]. Various factors affect the stages and efficiency of extraction, some of which are pH of sample solution, type and volume of ionic liquid, the time of ultrasonication, centrifuging time and rate, and the ionic strength of solution. In this research, optimum conditions were obtained as 55 μL of [C8MIM][PF6] selected as ionic liquid, pH 11, 2% NaCl, 4 min ultrasonication and 5 min centrifuging at 3500 rpm. Under the optimized conditions, the linearity was obtained in the range of 0.2 to 250 μg/L. The limits of detection were 0.5 μg/L for venlafaxine and 0.8 μg/L for amitriptyline. Pre-concentration factors were 1.3 × 103 for venlafaxine and 1.2 × 103 for amitriptyline. The UA−IL−DLLME method coupled with HPLC was successfully used for the determination of venlafaxine and amitriptyline spiked into the real samples of human plasma.

Prediction of the solubility of carbon dioxide in imidazolium based ionic liquids using the modified scaled particle theory

In this work, the solubilities of carbon dioxide in eight imidazolium based ionic liquids (1-ethyl-3-methyl imidazolium tetrafluoroborate [emim][BF4], 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide [emim][Tf2N], 1-n-butyl-3-methylimidazolium tetrafluoroborate [bmim][BF4], 1-n-butyl-3-methyl imidazolium hexafluorophosphate [bmim][PF6], 1-n-butyl-3-methylimidazolium bis(trifluoromethylsulf-onyl) imide [bmim][Tf2N], 1-n-octyl-3-methylimidazolium tetrafluoro borate[omim][BF4], 1-n-octyl-3-methylimidazolium hexafluorophosphate [omim][PF6], 1-n-octyle-3-methylimidazolium bis (trifluoro methylsulfonyl) imide [omim][Tf2N]) at different temperatures and pressures were obtained by using modified scaled particle theory (SPT), and the results were compared with the experimental values reported in the literature. In the SPT, the calculations of the solubility are related to the parameters and the physical properties of the solute and the ionic liquid, which all of them are temperature dependent. In this study, the effect of temperature on the molar volume of ionic liquid, the polarizability of carbon dioxide, the hard sphere diameter of ions and the hard sphere diameter of carbon dioxide have been considered in the calculations of carbon dioxide solubility in ionic liquids. By considering the effect of temperature on the mentioned parameters, the results are in better agreement with the experimental solubilities. In addition, the predicted results by the original and the modified SPT have been compared with those by the UNIFAC-Lei model. The total absolute average relative deviations (% AARD) for all systems were found to be 2.49%, 8.45% and 14.6% for the modified SPT, the original SPT and the UNIFAC-Lei model, respectively. Furthermore, the performance of various mixing rules have been elucidated in the SPT calculations for the estimation of carbon dioxide solubility in different ionic liquids.

Application of ionic-liquid-magnetized stirring bar liquid-phase microextraction coupled with HPLC for the determination of naphthoquinones in Zicao.

In this study, a green, rapid, and simple method, ionic-liquid-magnetized stirring bar liquid-phase microextraction was developed for the determination of naphthoquinones, including shikonin and β,β'-dimethylacrylshikonin, in Zicao. This method permits active magnetic stirring, extraction, and pre-enrichment in a single device simultaneously, so the extract is conveniently collected. The analytes were extracted from the sample to ionic liquid-magnetized stirring bar, then the analyte-adsorbed magnetized stirring bar can be readily isolated from the sample solution by a magnet. The key experimental parameters were investigated and optimized, including the type and volume of ionic liquid, extraction time, salt concentration, stirring speed, and pH. The recoveries were in the range of 89.47-102.38%, and good reproducibilities were obtained with relative standard deviation below 5.36%. Compared with the conventional extraction methods, the proposed method is quicker and more effective.

A simple, rapid and green ultrasound assisted and ionic liquid dispersive microextraction procedure for the determination of tin in foods employing ETAAS

This paper proposes a simple, rapid and green ultrasound assisted and ionic liquid dispersive microextraction procedure using pyrocatechol violet (PV) as complexing reagent and 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)-imide [C6MIM][Tf2N] as ionic liquid for the detection of tin employing electrothermal atomic absorption spectrometry (ETAAS). The optimization step was performed using a two-level full factorial design involving the following factors: pH of the working media, amount reagents, ionic liquid volume and extraction time and the chemometric response was tin recovery. The procedure allowed the determination of tin with limits of detection and quantification of 3.4 and 11.3 ng L−1, respectively. The relative standard deviation was 4.5% for a tin solution of 0.50 µg L−1. The validation method was confirmed by analysis of rice flour certified reference material. The method was applied for the quantification of tin in several food samples. The concentration range found varied from 0.10 to 1.50 µg g−1.