Hydrophilic Deep Eutectic Solvents Research Articles

A new green approach to synthesizing MIP-202@porous silica microspheres for positional isomer/enantiomer/hydrophilic separation

Metal-organic frameworks (MOFs) with superior physicochemical properties have great potential for applications in chromatographic separation. However, currently popular methods for the synthesis of MOF-based silica composite materials usually require the use of harmful organic solvents and long-term high-temperature sealing reactions. In order to respond to the needs of green chromatography, it is urgent to develop a new green organic-solvent-free strategy for the synthesis of MOF@SiO2 composites. MIP-202 is a zirconium-MOF constructed from zirconium ion and L-aspartic acid, which features green synthesis as well as good hydrolytic stability and chemical stability. In this paper, SiO2-NH2 was first prepared in a hydrophilic deep eutectic solvent, and then an amino acid-based MOF material (MIP-202) was modified on the surface of the SiO2-NH2 in an aqueous solution to obtain a MIP-202@SiO2 composite material. The multi-mode separation performance of MIP-202@SiO2 as a promising liquid chromatographic stationary phase was particularly evaluated and the separation mechanisms were discussed. The MIP-202@SiO2 column exhibited excellent separation ability for aromatic positional isomers. In addition, chiral enantiomers and hydrophilic analytes were also satisfactorily detected and separated. This work provides a new approach for the facile synthesis of MOF-based liquid chromatographic separation material by using green deep eutectic solvent and water as the reaction media.

The usability of green deep eutectic solvents in hollow fiber Liquid-Phase microextraction for the simultaneous extraction of analytes of different Natures: A comprehensive study

In the current study, a wide range of deep eutectic solvents (DESs) with different properties (hydrophilic, hydrophobic, ionic, and nonionic) were prepared in the initial phase. Subsequently, an assessment was conducted to evaluate some characteristics of the produced DESs, including their stability at room temperature and their capacity to extract three distinct types of analytes (anionic, cationic, and non-ionic) simultaneously through hollow fiber-liquid phase microextraction (HF-LPME) technique. To carry out the extraction procedure, the prepared DESs were inserted into the pores (as supported liquid membrane (SLM)) and lumen of hollow fiber membrane (HF) to apply two-phase and three-phase HF-LPME techniques. After a thorough evaluation, the three-phase HF-LPME technique (HF(3)-LPME) was chosen by using a mixture of menthol/TBAB-based hydrophobic DES (DES-35) as SLM and the mixture of malic acid/citric acid/water-based hydrophilic DES (DES-2) as an extraction solvent in the lumen of HF. All factors affecting the extraction recovery (including pH, extraction time, extraction temperature, stirring speed, and salt effect) were optimized utilizing the one-variable-at-a-time (OVAT) methodology. After applying the extraction procedure, all extracted samples were analyzed using the UV–Vis spectrometer and results were recorded at different wavelengths including 655 nm for Methylene blue, 550 nm for Amaranth, and 375 nm for Quercetin. The calibration graphs showed linearity in the range of 20.0–1500 µg/L, with a limit of detection of 6.2–15.1 µg/L and correlation coefficients higher than 0.9913 for the studied analytes. Moreover, the intra-day RSD, inter-day RSD, preconcentration factor (PF), enrichment factors (EF), and extraction recoveries (ER%) were obtained in the range of 3.1–4.8, 3.8–6.7, 125, 102.9–111.4, and 82.3–89.1 %, respectively. The use of the selected DES in the HF-LPME methodology resulted in an ecologically friendly strategy, as evidenced by the use of green metrics from the SPMS tool. The proposed strategy is also considered environmentally friendly due to its use of minimal solvents, waste reduction, and low energy consumption. The proposed technique effectively and simultaneously extractedmethylene blue, amaranth, and quercetin analytes in different real samples.

Development of magnetic matrix solid phase dispersion method for the extraction of crystal violet and rhodamine B from sediments based on magnetic ZIF-8 and a deep eutectic solvent

A magnetic matrix solid phase dispersion (MSPD) method based on magnetic ZIF-8 (SDS@MZIF-8) and a deep eutectic solvent was developed and used to the extraction of crystal violet and rhodamine B in lake sediments. SDS@MZIF-8 was prepared and used as the extraction sorbent and dispersant in MSPD. The magnetic property of MZIF-8 facilitated the recovery of the extraction sorbent after the blending step. Hydrophilic deep eutectic solvents were prepared and used as efficient green dispersing solvents in MSPD. The use of magnetic sorbent in MSPD is simple and fast, eliminating some additional steps commonly used in the classical MSPD and shortening the extraction time. The parameters influencing the extraction efficiency were investigated and optimized. Under the optimized conditions, the intra- and inter-day relative standard deviations were less than 4.9 %. The linearity ranged from 2-400 µg g−1 with coefficients of determination higher than 0.9943. The detection and quantification limits of RB and CV varied between 0.3–0.5 μg g−1 and 1.0–1.8 μg g−1, respectively. Finally, the developed method was applied to the analysis of RB and CV in the sediment samples. The recoveries ranged from 93.2 to 107.3 % and the relative standard deviations ranged from 0.8 to 4.9 %. The results suggest a high potential use of the proposed method to determine the organic pollutants in solid samples. Compared with the conventional MSPD extraction technique, the developed method considerably reduced the sample and solvent consumption, offering important environmental benefits.

Simultaneous and selective extraction of different polarity bioactive substances from Ligustri Lucidi Fructus based on a designable biphasic deep eutectic solvent

Most plants contain hydrophilic and hydrophobic bioactive compounds, traditional organic solvent extraction processes can often only extract one of the components, resulting in a cumbersome process and a waste of resources. To make full use of the active resources in Ligustri Lucidi Fructus, a biphasic deep eutectic solvent (DES) system was established. By adjusting the polarity, oleanolic acid (OA) and ursolic acid (UA) were enriched in the hydrophobic phase, and flavonoids and procyanidine (PAC) in the hydrophilic phase, respectively. Established with a 1:1 vol ratio of hydrophobic DES MIA (DL-menthol: isopropyl alcohol, 1:1) and hydrophilic DES CBE (choline chloride: betaine: ethylene glycol, 1:1:2). The biphasic system had the highest extraction rate. The response surface method was used to further optimize the extraction conditions. After optimization, the extraction yields of OA and UA were 10.96 ± 0.35 mg/g and 11.67 ± 0.26 mg/g in the MIA phase, and the extracted yields of flavonoids and PAC in the CBE phase were 77.38 ± 0.62 mg/g and 5.20 ± 0.03 mg/g, respectively. Compared with the conventional single-phase extraction with organic solvents, the biphasic system provided higher extraction rate and selectivity and the extracts showed stronger antioxidant activity. Compared to the single-phase extraction utilizing conventional organic solvents, the results demonstrated significant improvement. Consequently, by adjusting the polarity of the biphasic DES system, this study supplies an argument for increasing the extraction efficiency of plant resources. This expands the application of the biphasic DES system and contributes to the high-value exploitation of natural commodities.

Switchable hydrophilicity solvents incorporating hydrophilic deep eutectic solvents: A sustainable alternative for oil-based drilling cuttings washing

Oil-based drilling cuttings (OBDC) contaminated by total petroleum hydrocarbons (TPH) causes detrimental environmental consequences. Solvents washing is capable of separating TPH from OBDC efficiently, but their high volatility and toxicity limit the large-scale application. Here a sustainable OBDC washing strategy is developed by using a heterogeneous mixture (SHSs&HDESs) which is consisted of switchable hydrophilicity solvents (SHSs) and hydrophilic deep eutectic solvents (HDESs). N, N-Dimethylcyclohexylamine (DMCHA) and CHEG (choline chloride/ethylene glycol) is respectively selected as the optimum SHSs and HDESs, considering the miscibility with TPH and recovery capacity. The advantage of the sustainable washing strategy originates from the synergistic effect for enhancing forward the TPH removal efficiency, where DMCHA plays the role on TPH extraction and dilution, and CHEG promotes the detachment of TPH from sands surfaces. Based on the Box-Behnken experimental design of response surface method, the TPH removal efficiency reaches a maximum value of 96.02 % at the derived optimal washing conditions, including 32 °C, 19.81 mL DMCHA, and 9.62 mL CHEG. TPH can be separated from DMCHA by CO2-induced hydrophobicity transformation, DMCHA is recovered upon N2/65 °C afterwards, and CHEG is recovered by liquid separation. The recovered SHSs&HDESs heterogeneous mixture shows good reusability in subsequent OBDC washing processes. Our findings offer a sustainable approach for efficiently OBDC washing, which is expected to overcome the inherent defects of solvents washing methods.

Critical overview on the use of hydrophobic (deep) eutectic solvents for the extraction of organic pollutants in complex matrices

During the last decades, many efforts have been devoted to the adaptation of sample preparation techniques and methods to the principles of Green Analytical Chemistry. Among them, this article review focusses on those aimed to green the solvents involved in sample treatment. Research in this field started in the late 1990s with the synthesis of room temperature ionic liquids, which were later replaced by the deep eutectic solvents (DESs). During the last years, a subclass of DESs, the so-called hydrophobic deep eutectic solvents (HDESs) have attracted attention. HDESs have contributed to circumventing some of the limitations of early-synthesised hydrophilic DESs regarding the cost of raw materials, the simplicity of synthesis, and the biocompatibility and, apparently, the biodegradability of the mixtures. In addition, these mixtures allowed the treatment of aqueous samples and the extraction of non-polar analytes.This article discusses fundamental aspects regarding the nomenclature used concerning HDESs, summarises the main physicochemical properties of these mixtures, and through discussion of key application studies, describes current progress in the use of these green solvents for the extraction of trace organic contaminants from a variety of matrices. Remaining gaps and possible lines of future development in this emerging, active and attractive research area are also identified and critically discussed.

Experimental density and volumetric properties of DESs based on tetrabutylammonium bromide and used for effective extraction of naphthol green B and malachite green

AbstractBACKGROUNDTo improve the quality of wastewater and thereby to meet the standards as per environmental production agency in US and UK. In the present work, Malachite green (MG) and Naphthol Green B (NGB) has been taken as model dyes in wastewater. Solvent extraction process was carried out using deep eutectic solvents (DESs) as an alternative solvent for organic and ionic liquids.RESULTSThe possible molecular interaction between DESs and selective dyes in water were analyzed and discussed in details using volumetric properties including excess molar volume , partial molar volume , excess partial molar volume , apparent molar volume , isobaric thermal expansion () and excess isobaric thermal expansion (αE). Further, the extraction of selective dyes was conducted and characterized in terms of extraction efficiency (η), effect of temperature on extraction efficiency, effect of shaking time on extraction efficiency, effect of concentration on extraction efficiency, effect of HBD on extraction efficiency, distribution coefficient (D). Finally, the thermodynamic extraction feasibility was analysed by means of Gibbs free energy , change in enthalpy , and change in entropy .CONCLUSIONThere is possible molecular interaction between hydrophilic DESs and NGB/MG in water at molecular level. 96% of extraction efficiency was obtained for NGB using hydrophobic DESs like {[TBAB][DA]} and {[TBAB][OA]} whereas {[TBAB][DA]} and {[TBAB][OA]} gave above 72% removal efficiency of MG. Finally the thermodynamic feasibility of extraction process was analyzed and discussed. © 2023 Society of Chemical Industry (SCI).

Synthesis of tunable hydrophilic deep eutectic solvent for the extraction of antioxidants from Salvia officinalis L.

The leaves of Salvia officinalis L., a plant known for its high antioxidant content, were selected as the focus of this research. This research aimed to evaluate the antioxidant activity of sage leaves extract by varying the hydrophilic deep eutectic solvents (DESs) compositions and molar ratios. The hydrophilic DESs were synthesized using the heating method with diverse combinations of DES, including lactic acid (LA), oxalic acid (OA), succinic acid (SA), and ethylene glycol (EG) as hydrogen bond donors (HBDs) and choline chloride (ChCl) as the sole hydrogen bond acceptor (HBA) with varied molar ratios of HBA to HBD (1:1, 1:2, and 2:1). The antioxidants were extracted using ultrasound-assisted extraction method at 70°C of extraction temperature, 30 mins of sonication time, and 1:30 g/mL of solid-solvent ratio. The DES extraction efficiency was evaluated based on the antioxidant scavenging abilities measured by α, α-diphenyl-β-picrylhydrazyl (DPPH) free radical scavenging assay. The results revealed that the ChCl-OA showed the highest antioxidant activity (67.660 μg/mL), followed by ChCl-EG (52.327 μg/mL) and ChCl-LA (33.116 μg/mL) with molar ratios of 1:1, 1:2 and 1:2, respectively. As conclusion, ChCl-OA with molar ratio of 1:1 exhibited the highest extraction efficiency (77.259%) as compared to the other DES combinations using 70% of methanol (v/v).

Hydrophilic deep eutectic solvent based microextraction procedure for the determination of four paraben preservatives in vitamin D for babies: A green approach

In this study, an easily available, sensitive, and fast hydrophilic deep eutectic solvent-liquid phase microextraction method developed using deep eutectic solvent (DES) as a green solvent for the determination and microextraction of paraben (methyl, ethyl, propyl, and butyl) preservatives in vitamin D for babies. The highest yield for extraction recovery was obtained using DES consisting of a 1:4 M ratio of choline chloride and acetic acid. Moreover, various optimization parameters such as DES volume, DES type, sample volume, and centrifugation time were investigated in order to develop a real sample specific microextraction method. Relative standard deviation values were 0.92%-2.87%, the detection limit was 0.194–0.254 µg/mL, and extraction recovery values were between 87.40% and 102.98%. The method developed in this study was successfully applied to 5 different babies in vitamin D for babies obtained from pharmacies for the determination of methyl, ethyl, propyl, and butylparaben. As far as we know, it is the first study conducted both in terms of the determination of paraben preservatives in vitamin D for babies and in terms of the fact that DES used in this study is used for the first time in vitamin D for babies.

Hydrophilic and hydrophobic deep eutectic solvent-based extraction to determine parathion in cereals by digital image colorimetry integrated with smartphones

To determine parathion in cereals, hydrophilic and hydrophobic deep eutectic solvents (DESs) were used by digital image colorimetry with smartphones. In the solid-liquid extraction part, hydrophilic DESs were used as extractants to extract parathion from cereals. In the liquid-liquid microextraction part, hydrophobic DESs dissociated into terpineol and tetrabutylammonium bromide in situ. The dissociated hydrophilic tetrabutylammonium ions reacted with parathion extracted in hydrophilic DESs under alkaline conditions to produce a yellow product, which was extracted and concentrated by dispersed organic phase terpinol. Digital image colorimetry integrated with the use of a smartphone was used for quantitative analysis. The limit of detection and quantification were 0.003 mg kg−1 and 0.01 mg kg−1, respectively. The recoveries for parathion were 94.8–106.2% with a relative standard deviation less than 3.6%. The proposed method was applied to analyze parathion in cereal samples: the method has the potential to be applied to pesticide residue analysis in food products.

Multielemental analysis of oils and animal fat by using deep eutectic solvents assisted by an aerosol phase extraction procedure

In the present study, thirteen elements (Ag, Al, Ba, Cd, Cr, Cu, Fe, K, Li, Mg, Mn, Ni, Pb) have been extracted from used cooking oils, olive oils and animal fat. Either inductively coupled plasma optical emission spectrometry (ICP-OES) or tandem mass spectrometry (ICP-MS/MS) have been chosen as detection techniques. Due to the difficulty of directly introducing highly viscous organic samples into the spectrometer, a fast dispersive liquid – liquid aerosol phase extraction (DLLAPE) method has been selected to isolate the analytes from the sample matrix. The DLLAPE is based on the generation of an aerosol from the extracting phase with the help of a pneumatic nebulizer. This high velocity aerosol impacts and penetrates in the liquid sample. Consequently, the liquid – liquid exchange surface area becomes high, thus leading to high extraction yields. A hydrophilic deep eutectic solvent (DES) consisting of choline chloride and ethylene glycol (1:2 mass ratio) has been selected as the extracting solvent. Prior to undertaking the experiments, the extraction method has been evaluated in terms of precision under suitable conditions. In comparison with conventional methods based on sample digestion, sample dilution and shot analysis or extraction assisted by vortex agitation, the DLLAPE shows several advantages, because it is faster, and it provides lower limits of detection than the reference methodologies. The procedural limits of quantification for the determined elements with the DLLAPE in ICP-OES were 0.046 (Ag), 0.396 (Al), 0.013 (Cd), 0.033 (Cr), 0.040 (Cu), 0.20 (Fe), 0.026 (K), 0.026 (Li), 0.33 (Mg), 0.013 (Mn), 2.64 (Ni) and 0.53 (Pb) mg kg−1. Meanwhile, pLOQ in ICP-MS/MS lowered by roughly one order of magnitude. The accuracy of the aerosol phase extraction method has been evaluated through the determination of the recoveries for four representative analytes (Ca, Cu, Mg and Ni) from spiked real samples. For these elements, recovery has taken values of (100 ± 20)%. Moreover, a comparison of the multielemental concentration obtained with conventional methods (c.a., sample dilution and shot ICP analysis and liquid-liquid extraction using a vortex agitator) against that measured with the DLLAPE has been carried out. Multiemelemental concentrations have been obtained for real samples and the found levels have been similar to those encountered in previously published works.

Evaluation of blood BTEX levels in fuel stations workers using vortex-assisted dispersive liquid-liquid microextraction based on deep eutectic solvent followed by gas chromatography flame-ionization detector

In this research, an eco-friendly method was established by vortex-assisted dispersive liquid-liquid microextraction based on the deep eutectic solvent (VA–DLLME–DES). The performance of the proposed method was demonstrated by the determination of benzene, toluene, ethylbenzene, and xylene (BTEX) in blood samples of fuel stations workers combined with GC–FID. The selected hydrophilic deep eutectic solvent is consisting of l-menthol and (1S)-(+)-camphor-10-sulfonic acid (CSA) at a 5:1 molar ratio as a green solvent instead of traditional toxic organic solvents. Under the optimal extraction conditions, the introduced method exhibited good linearity with a coefficient of determinations (r 2) higher than 0.9985 and an acceptable linear range of 0.03–80 µg l–1. Accordingly, the limits of detection (S/N = 3) and limits of quantification (S/N = 10) were in the ranges of 0.01–0.04 µg l−1 and 0.03–0.10 µg l−1, respectively. Blood BTEX levels of fuel stations workers were analyzed based on age, duration of working at the station, smokers or nonsmokers, and station type (CNG, gasoline, and dual-purpose). The results showed that there was no significant difference between blood BTEX levels in different age groups, while the concentration of BTEX compounds increases with the increase of working time in the station. Blood BTEX levels were much higher in smokers than in nonsmokers.

A simple HPLC-DAD method for analysis of phenolic acids: Addition effect of a hydrophilic deep eutectic solvent to the mobile phase

AbstractThe analysis of phenolic acids (PAs) is of great importance, because they are frequently present in natural products and their derivatives, and these compounds also have multiple beneficial effects to human health. This work is focusing on the separation of seven PAs (caffeic acid, coumaric acid, gallic acid, ferulic acid, protocatechuic acid, sinapic acid, and syringic acid), in a reversed-phase liquid chromatographic (RP-HPLC) isocratic method using a hydrophilic deep eutectic solvent (DES) as a mobile phase additive. The analysis was carried out with a diode array detector. The used DES was composed by choline chloride and glycerol, and it was characterized by infrared spectroscopy. The combination of choline chloride:glycerol (1:4) added at 0.25% to mobile phase composed of 0.15% formic acid aqueous solution and methanol (80:20), showed the best separation for target analytes. The new proposed method was validated, and results indicated that the proposed method is linear, selective for almost all analytes, provided high sensitivity with limit of detection ranges from 0.009 to 0.023 mg mL−1, and has satisfactory precision and accuracy, with values of relative standard deviation of 0.24–2.65% and recoveries of 97.97–109%, respectively. Additionally, this method was successfully applied to simultaneous determination of phenolic acids in three kinds of samples of powder to prepare lemon flavour drink enriched with black tea extract.

New Class of Tunable Choline Bromide-Based Hydrophobic Deep Eutectic Solvents for the Extraction of Bioactive Compounds of Varying Polarity from a Plant Matrix.

Deep eutectic solvents (DESs) are a class of sustainable solvents that have found numerous applications in different fields. One of their main attributes is the possibility of easily modifying their physicochemical properties by varying the type of hydrogen bond donor (HBD) and hydrogen bond acceptor (HBA) that comprise them. Choline chloride ([Ch+][Cl-])-based hydrophilic DESs were among the first studied and the most used because of their capacity to easily create a hydrogen bonding network that lies in its unique chemical structure, characterized by a hydroxyl substituent within the ammonium headgroup. In this study, a new class of hydrophobic [Ch+][Br-]-modified salts were synthesized to produce HBAs with similar properties to choline for the preparation of hydrophobic DESs. Six different [Ch+][Br-]-based HDESs were prepared and characterized in terms of hydrophobicity, viscosity, and solvation properties (hydrogen bonding, dispersion, dipolarity/polarizability, n-π, and π-π interactions). They were employed as solvents in a microextraction method for the determination of phytochemicals in Cannabis sativa L. plant. The extraction performance of the [Ch+][Br-]-based HDESs was compared to eutectic mixtures based on conventional hydrophobic HBAs, and the results revealed that the unique properties of [Ch+][Br-]-modified salts allowed for the extraction of both hydrophilic (i.e., flavonoids) and hydrophobic compounds (i.e., cannabinoids).

Green solvents for the selective extraction of bioactive compounds from by-products of the coffee production chain

Approximately 15–20 million tonnes of by-products were generated globally in the coffee production chain during the 2020/21 season. The current uses for these by-products are inadequate or contribute to environmental degradation. This work reports the screening of hydrophilic and hydrophobic solvents, including deep eutectic solvents (DES), for their ability to extract the valuable metabolites caffeine and chlorogenic acid (markers in commercial extraction) from four coffee-related by-products. Water was the best solvent for recovering caffeine and chlorogenic acid from defective green coffee beans, while all hydrophilic DES surpassed water in the extraction of chlorogenic acid from coffee pulp. For the two remaining by-products, at least one DES was as good or better at extracting the caffeine or chlorogenic acid compared to water. The array of hydrophobic solvents tested here showed different selectivities, allowing the annotation of 12 compounds that have not been previously reported in coffee by-products. These results demonstrate the ability to obtain a new and controllable range of extracts from coffee by-products using green and functional solvents.

Using novel hydrophobic deep eutectic solvents to improve a sustainable carotenoid extraction from orange peels

Carotenoids are a group of pigments that play a significant role in human health due to their antioxidant properties. This emphasises the importance of their extraction using sustainable solvents as alternatives to hazardous solvents. This study aimed to select and optimise the most promising deep eutectic solvent (DES) for a sustainable carotenoid extraction from orange peels by considering parameters such as efficiency, stability, and physicochemical properties. COSMOtherm software was used to screen 68 hydrophobic and hydrophilic DES. The experimental results demonstrated efficient extraction yields when using hydrophobic DES such as Menthol: Camphor (163.5 ± 1.1 mg/100gfw), and the stability of carotenoids in this solvent was 56% for total carotenoids after 60 days at 4 °C. The ultrasound extraction technique was selected for the optimisation process, and the optimal conditions were 60% ultrasound intensity (120 W), a solvent-to-solid ratio of 20 mL, and an extraction time of 20 min with a yield of 653.5 mg/100 gfw. The results presented in this study demonstrate the capacity of novel hydrophobic DES to extract carotenoids and identify this solvent as a good and sustainable alternative to organic solvents. Improved carotenoid extraction combined with non-toxicity, edibility, and enhanced carotenoid stability makes these extracts appealing for use in food product fortification.

Switchable deep eutectic solvents for sustainable extraction of β-carotene from millet

Switchable deep eutectic solvents (DESs) were combined with phenolic antioxidants to extract β-carotene from millet, and the recovery and reuse capacities of DESs were evaluated. The pre-treatment of millet using ultrafine grinding is beneficial to the extraction of β-carotene. The hydrophobic DESs synthesized from N,N-dimethylcyclohexylamine and n-butanol were used as the extractants for grinding-assisted extraction of β-carotene from millet, and phenolic antioxidants were used to improve the stability of β-carotene. The hydrophobic DESs were switched to hydrophilic DESs by adjusting pH to recover the hydrophobic β-carotene solid. The remaining hydrophilic DESs could be switched to hydrophobic DESs by adjusting pH to extract new millet samples. In five DES recovery and reuse processes, the yield did not decrease, and more than 91.0% of β-carotene from millet could be directly recovered in solid state each time. In summary, a rapid, efficient, and sustainable method for β-carotene extraction was developed.

Green approach to extract bioactive compounds from orange peel employing hydrophilic and hydrophobic deep eutectic solvents

Consumer interest in natural products with advantageous biological impacts on their health has increased in recent years. Therefore, academic and industrial communities have concentrated their research on developing sustainable techniques for extracting bioactive compounds from natural resources. In the present study, extracts rich in bioactive compounds from orange peel were obtained using novel hydrophilic and hydrophobic deep eutectic solvents (DESs). Bioactive compounds such as carotenoids and polyphenols, their stability, antioxidant capacity, permeability, and biological activity were determined to consider their inclusion in food formulations. The results demonstrated that the highest total carotenoid values were obtained with hydrophobic DESs using DL-Menthol: camphor (163.5 ± 1.1 mg/100gfw), DL-Menthol: Eucalyptol (168.7 ± 1.7mg/100gfw), and lauric acid: octanoic acid (153.1 ± 7.1 mg/100gfw). Total polyphenols were higher in hydrophilic DESs such as proline: malic acid (282.8 ± 7.3 mg/100gfw). The antioxidant values showed that hydrophobic extracts have higher antioxidant activity than traditional solvents. Carotenoid stability was also improved using DL-Menthol: camphor, while lactic acid: glucose and proline: malic acid showed a better capacity to stabilize polyphenols. To simulate carotenoid and polyphenol permeation, the Parallel Artificial Membrane Permeability Assay (PAMPA) was used and demonstrated that DESs can enhance the permeability of these bioactive compounds. Biological tests were also performed, and the antiproliferative effect in HeLa cells showed only 26.70% cell viability in DL-Menthol: camphor extracts. Based on the presented results, DESs can be used to extract hydrophilic and hydrophobic compounds from orange peels, and the obtained extracts could be included in food formulations, avoiding the solvent elimination process.

Diffusivities and solubilities of carbon dioxide in deep eutectic solvents

Deep eutectic solvents (DESs) have been identified as promising solvents for CO2 capture because of their low volatility and tunable properties. Detailed information on solute solubility and diffusivity is crucial for the design and operation of processes involving mixtures composed of DESs and dissolved gases. The infinite-dilution diffusion coefficients of CO2 in 33 DESs (both hydrophilic and hydrophobic) were gravimetrically determined with a magnetic suspension balance at 298.15 and 313.15 K along with the Henry’s constants of CO2 in these DESs. Interestingly, the diffusion coefficients of CO2 at infinite dilution in hydrophobic DESs were found to be much higher than those in hydrophilic DESs. In order to better understand this phenomenon, CO2 diffusion coefficients under infinite dilution conditions in traditional solvents and ionic liquids (ILs) were summarized from literature, which revealed that the CO2 diffusivity is often approximately inversely proportional to the square root of the viscosity. However, the hydrophilic DESs and some ILs/hydrophobic DESs with large molar volumes displayed a significantly different behavior. The OH group seems to hinder CO2 diffusion, while the presence of multiple long flexible alkyl chains in the DES constituents can facilitate the diffusion. Modified Wilke–Chang correlations were successfully developed to describe the infinite-dilution diffusion coefficients in the measured DESs. Tetraoctylammonium bromide - decanoic acid (1:2) was found promising for further investigation for application in CO2 capture processes with supported liquid membranes or physical absorption.

Evaluation of blood lead levels in opium addicts and healthy control group using novel deep eutectic solvent based dispersive liquid-liquid microextraction followed by GFAAS.

Today, drug dealers and sellers add lead compounds to these substances to get more profit. As a result, drug users are heavily exposed to lead, and lead poisoning is clearly seen in most of them. Therefore, it is especially important to check the blood lead levels in these people. In this research, an efficient and eco-friendly pretreatment method was established by deep eutectic solvent for dispersive liquid-liquid microextraction (DES - DLLME) followed by graphite furnace atomic absorption spectrometry (GFAAS) analysis. The selected hydrophilic deep eutectic solvent consists of l-menthol and (1S)-( +)-camphor-10-sulfonic acid (CSA) at a 5:1 molar ratio as a green solvent instead of traditional toxic organic solvents. Under the optimal extraction conditions, the introduced method exhibited good linearity with coefficient of determination (r2) 0.9975 and an acceptable linear range of 0.3-80µg L-1. Accordingly, the detection limit was 0.1µg L-1 (S/N = 3) for lead ions, and the high enrichment factor (240) was obtained. The proposed method was successfully applied to analysis lead ions in real blood samples, which is a promising technique for biological samples. The case samples were classified and analyzed based on age, duration of consumption, and type of substance. The results showed that there was no significant difference between blood lead levels in different age groups and different duration of use, while blood lead levels were higher in opium residue (shireh) users than in opium users.