Volume Of Deep Eutectic Solvent Research Articles

Ultrasound-assisted emulsification liquid phase microextraction method based on deep eutectic solvent as extraction solvent for determination of five pesticides in traditional Chinese medicine

A kind of green solvents termed deep eutectic solvent (DES) have been considered alternatives to traditional organic solvents. In this study, a method was developed for determination of five pesticide residues including triadimenol, fipronil, tebuconazole, hexaconazole and diniconazole in five different traditional Chinese medicines (TCMs). In the developed method, DES was selected as extraction solvent, ultrasound-assisted emulsification liquid phase microextraction (UA-ELPME) was used for extraction and high performance liquid chromatography (HPLC) equipped with a diode array detector (DAD) was used for quantification. In this method, DES was synthesized with choline chloride and phenol at the molar ratio 1:4 using the heating and stirring method. Meanwhile, several important parameters such as volume of DES (650 μL), volume of tetrahydrofuran (THF, 550 μL) and ultrasonic time (30 min) were optimized by using response surface methodology (RSM) based on a central composite design (CCD). Under the optimized conditions, the limits of detection and quantification of method were in the range of 0.02-0.2 μg mL−1 and 0.05-0.5 μg mL−1, respectively. The correlation coefficients (r) of five calibration curves are greater than 0.9996, relative standard deviation (RSD) of precision for this method of five pesticides were lower than 4.7%, and the mean recoveries were in the range of 81.0–92.1%. The present experiment suggests that DESs are efficiently extract solvents in UA-ELPME method for traditional herbal medicines applications.

Green determination of brominated flame retardants and organochloride pollutants in fish oils by vortex assisted liquid-liquid microextraction and gas chromatography-tandem mass spectrometry

A "green", simple, and low-cost sample extraction procedure involving the use of a deep eutectic solvent (DES) in a vortex assisted liquid-liquid microextraction (VALLME) technique followed by gas chromatography-tandem mass spectrometry (GC-MS/MS) analysis was developed for the simultaneous determination of different PBDEs congeners and OCPs residues in fish oils. After evaluation of different eutectic mixtures, the extraction parameters (volume of DES, amount of oil sample and extraction time) were optimized by means of experimental design in order to maximise extraction efficiency. The developed method was validated in terms of linearity, accuracy and precision, presenting limits of detection in the low ng g−1 level. Its application in the analysis of five fish oil samples, allowed the detection of all the target analytes at levels up 21.5 ng g−1. Fish oils used in animal feed showed to be more contaminated than fish oils for human consumption.

A rapid ultrasonic energy assisted preconcentration method for simultaneous extraction of lead and cadmium in various cosmetic brands using deep eutectic solvent: A multivariate study

An innovative ultrasonic assisted microextraction method using a deep eutectic solvent for entrapping the organ metallic complexes was developed to pre-concentrate the trace quantities of cadmium (Cd) and lead (Pb) in lipsticks and eye shadows of different brands prior to flame atomic absorption spectrometry analysis. A deep eutectic solvent (DES) was used in this study, prepared by mixing metal salt (ZnCl2) and hydrogen bond donors such as (acetamide) in different ratio. The different branded cosmetic items, lipstick and eye shadows, obtained from local market and subjected to acid digestion prior to application of proposed ultrasonic assisted microextraction method based on deep eutectic solvent (UAµE-DES) with the aid of mechanical and ultrasound energies. Ammonium pyrrolidine dithiocarbamate was used as a ligand to made hydrophobic complexes of Cd and Pb, entrapped in DES in the presence of aprotic solvent. The seven variables, mixing ratio of ZnCl2 and Acetamide, DES volume, Ultrasound and Conventional shaking time, pH, tetrahydrofuran and complexing reagent volume were optimized by multivariate approach for the optimum recovery of Cd and Pb from real cosmetic items. The resulted data indicates that ultrasound energy assisted extraction time, volume of DES and pH were most significant variables. The precision and validity of developed procedure were checked by the spiked known certified standards in real samples. The resulted data indicated that the lipsticks have different glittering colors contains high contents of Pb and Cd, whereas dark colors of eye shadows contain high level of both elements.

Centrifugation free and air-assisted liquid-liquid microextraction based on deep eutectic solvent for determination of rare ginsenosides in Kang'ai injection

A simple, effective and convenient enrichment method coupled with high performance liquid chromatography (HPLC) was established for the analysis of rare ginsenosides in Kang'ai (KA) injection. Air assisted liquid-liquid microextraction was used in this work for the first time to determine the rare ginsenosides in KA injection. Deep eutectic solvent (DES) and tetrahydrofuran (THF) were specially selected as a novel green extraction solvent and an emulsified solvent, respectively. To remove the DES droplets, Fe3O4 nanoparticles were used. Therefore, centrifugation was free in this work, which can increase the efficiency of analysis procedure. Moreover, Fe3O4 nanoparticles were reusable. To achieve better extraction efficiency and enrichment factor, the experimental conditions have been optimized, including type and volume of DES and emulsified solvent, amount of Fe3O4 nanoparticles and inorganic salt, and pH value. Under the optimum extraction condition, the validation parameters show the limits of detection (LODs) are in the range from 10.2 ng/mL to 137.8 ng/mL and the limits of quantity (LOQs) are in the range from 55.5 ng/mL to 428.5 ng/mL. The recoveries of analytes range from 91.3% to 106.7% with the relative standard deviations (RSDs) ranging from 1.2% to 4.5%. The recommended approach was utilized to acquire the information of constituents in KA injection. Moreover, the results in this research could provide a study basis for further study of KA injection.

A highly selective and sensitive ultrasonic assisted dispersive liquid phase microextraction based on deep eutectic solvent for determination of cadmium in food and water samples prior to electrothermal atomic absorption spectrometry

A simple, fast, green, sensitive and selective ultrasonic assisted deep eutectic solvent liquid-phase microextraction technique was used for preconcentration and extraction of cadmium (Cd) in water and food samples by electrothermal atomic absorption spectrometry (ETAAS). In this technique, a synthesized reagent (Z)-N-(3,5-diphenyl-1H-pyrrol-2-yl)-3,5-diphenyl-2H-pyrrol-2-imine (Azo) was used as a complexing agent for Cd. The main factors effecting the pre-concentration and extraction of Cd such as effect of pH, type and composition of deep eutectic solvent (DES), volume of DES, volume of complexing agent, volume of tetrahydrofuran (THF) and ultrasonication time have been examined in detail. At optimum conditions the value of pH and molar ratio of DES were found to be 6.0 and 1:4 (ChCl:Ph), respectively. The detection limit (LOD), limit of quantification (LOQ), relative standard deviation (RSD) and preconcentration factor (PF) were observed as 0.023 ng L−1, 0.161 ng L−1, 3.1% and 100, correspondingly. Validation of the developed technique was observed by extraction of Cd in certified reference materials (CRMs) and observed results were successfully compared with certified values. The developed procedure was practiced to various food, beverage and water samples.

Vortex assisted deep eutectic solvent (DES)-emulsification liquid-liquid microextraction of trace curcumin in food and herbal tea samples

We developed a new microextraction method for separation and preconcentration of curcumin using deep eutectic solvent known as green solvent. Deep eutectic solvent (DES) formed by mixing of choline chloride and phenol was used as an extraction solvent in microextraction study to extract the curcumin at pH 4.0. The curcumin concentration in enriched DES phase was analyzed by UV–Visible spectrophotometer. The effect of parameters such as pH, mol ratio of DES composition, volume of DES, volume of tetrahydrofuran (THF) and sample volume were examined. Interference effects of matrix components were investigated. The preconcentration factor was 12.5. The detection limit of method (n = 10) was 2.86 µg L−1 and the relative standard deviation (RSD, n = 8) was 1.8%. The method was successfully applied to determination of curcumin in food and herbal tea samples. The mean recoveries were between 96% and 102% and standard deviations were found in the range of 1–6%.

Ultrasonic assisted dispersive liquid-liquid microextraction method based on deep eutectic solvent for speciation, preconcentration and determination of selenium species (IV) and (VI) in water and food samples

A novel ultrasound-assisted liquid phase microextraction (UALPME) based on environmental friendly extractants, deep eutectic solvent (DES) was first time presented for speciation of selenium. In present study, five DES solvents of different composition was prepared and used as efficient extractive medium for hydrophobic chelate of Se(IV) with 3,3′-Diaminobenzidine (DAB). The total inorganic Se species were determined after pre-reduction of Se(VI) to Se(IV), prior to applying developed method. The concentration of Se(VI) was calculated by the difference of Se(IV) values and total selenium contents. The concentration of Se in DES rich phase was measured with electrothermal atomic absorption spectrometer (ETAAS). The effects of different parameters on extraction efficiency of study analyte, including pH, ligand concentration, type and volume of DES, sonication time, volumes tetrahydrofuran and aqueous samples were examined. At the optimum conditions, limit of detection and quantification, preconcentration factor, and relative standard deviation (RSD %) were determined as 4.61ngL−1, 15.4ngL−1, 50% and 4.1%, respectively. The accuracy of the presented method was confirmed by analysis of certified reference material and standard addition method for different water and ice tea samples. The developed method was effectively applied to real water and food samples.

Flow of deep eutectic solvent-simulated fuel in circular channels: Part II—Extraction of dibenzothiophene

Different fuel types are usually produced in refineries containing various sulfuric compounds, which have acute negative impact on the ecosystem and human beings in general. Extractive desulfurization (EDS) is a recently used technology in the treatment of these compounds. This research targets investigating experimentally the desulfurization of liquid fuel using deep eutectic solvent (DES) in continuous liquid–liquid microchannels at room conditions. This was done using a circular 1.22mm ID glass channel. The working fluids were simulated fuel with 200ppm dibenzothiophene (DBT) and a DES composed of tetra-n-butylammonium bromide (TBAB) and polyethylene glycol 200 with a molar ratio of 1:2 respectively. The DES density and viscosity at room temperature are 1094kg/m3 and 0.2Pa.s respectively, while those of simulated fuel are 739.4kg/m3 and 8×10−4Pa.s respectively. The effect of initial DBT concentration in the simulated fuel, mixture velocity, DES volume fraction and channel length on extraction of the DBT was investigated. The results indicated that the percentage extraction of the DBT is independent of the initial DBT concentration while it increased with the increase in DES volume fraction and channel length. The results also showed that the DBT extraction is fluctuating with respect to mixture velocity. The highest DBT extraction for the investigated conditions, which was 47%, was achieved at a DES volume fraction of 0.5, 50cm channel length and a mixture velocity of 0.2m/s. Finally, the overall volumetric mass transfer coefficient decreased with increasing the residence time (channel length) and increased with increasing the mixture velocity.