Hydrophobic Deep Eutectic Solvents Research Articles

Redox Biocatalysis in Lidocaine-based Hydrophobic Deep Eutectic Solvents: Non-conventional Media Outperform Aqueous Conditions.

Redox biocatalysis is an important pillar of the chemical industry. Yet, the enzymes' nature restricts most reactions to aqueous conditions, where the limited substrate solubility leads to unsustainable diluted biotranformations. Non-aqueous media represent a strategic solution to conduct intensified biocatalytic routes. Deep eutectic solvents (DESs) are designable solvents that can be customized to meet specific application needs. Within the large design space of combining DES components (and ratios), hydrophobic DESs hold the potential to be both enzyme-compatible - keeping the enzymes' hydration -, and solubilizers for hydrophobic reactants. We explored two hydrophobic DESs, lidocaine/oleic acid, and lidocaine/decanoic acid, as reaction media for carbonyl reduction catalyzed by horse liver alcohol dehydrogenase, focusing on the effect of water contents and on maximizing substrate loadings. Enzymes remained highly active and stable in the DESs with 20 wt.% buffer, whereas the reaction performance in DESs outperformed the pure buffer system with hydrophobic substrates (e.g., cinnamaldehyde to form the industrially relevant cinnamyl alcohol), with a 2-fold higher specific activity. Notably, the cinnamaldehyde reduction was for the first time performed at 800 mM (~100 g[[EQUATION]]L-1) with full conversion, which opens up new avenues to industrial applications of hydrophobic DESs for enzyme catalysis.

Salting-out Effects in Extraction of Phenol from Aqueous Solutions Using a Hydrophobic Deep Eutectic Solvent Based on Dodecanoic and Octanoic Acids: Experimental Study and Comparison

Salting-out Effects in Extraction of Phenol from Aqueous Solutions Using a Hydrophobic Deep Eutectic Solvent Based on Dodecanoic and Octanoic Acids: Experimental Study and Comparison

Rapid and eco-friendly microextraction procedure based on green hydrophobic deep eutectic solvent for simultaneous determination of five sex hormones from cosmetic samples

Hormones, which are among the endocrine disruptors, are used in many fields and their use in cosmetic products has recently attracted considerable attention. Despite the negative health consequences, there is no detailed guidance that limits the use of these endocrine disruptors. This study aimed to develop a green hydrophobic deep eutectic solvent (HDES)-based microextraction method for the detection and quantification of sex hormones (progesterone, β-estradiol, estrone, ethinylestradiol, and testosterone) in different cosmetic products. The best value for extraction recovery was obtained by using DL-menthol and dodecanoic acid as green HDES in a 4:1 mole ratio. Optimization parameters such as HDES volume, pH, sample volume, centrifugation time, mixing type, and mixing time were investigated for cosmetic samples to be used as real samples. Furthermore, the extraction recovery values ranged from 85.7 % to 101.3 % and the detection limit was between 2.33–3.30 ng mL−1. Additionally, three different greenness methods, namely ComplexGAPI, AGREEprep, and BAGI, were used to evaluate how green the proposed method is in this study. The microextraction procedure developed in this study was successfully applied to five different cosmetic samples that will be used as real samples to detect and determine sex hormones.

Mechanistic insights into lipid extraction from wet microalgae using hydrophobic deep eutectic solvents under hydrothermal conditions

Hydrophobic deep eutectic solvents (HDESs) were first employed under hydrothermal conditions to form a two-phase system for instantaneous and efficient lipid extraction from wet microalgae, preventing lipid degradation and avoiding the use of toxic solvents. Ten HDESs were assessed for their efficiency and selectivity in lipid extraction. Among them, OCT-DEC, composed of octanoic acid and decanoic acid, achieved the highest extraction efficiency at 95.42 %, while also preventing the co-extraction of proteins and reducing sugars. Molecular dynamics simulations revealed that lipid extraction efficiency is primarily influenced by lipid-HDES interactions, which drive lipid diffusion, and the interfacial properties of the two-phase hydrothermal system, which resist lipid diffusion. The superior performance of OCT-DEC is attributed to its high hydrogen bond density and short bond lifetimes, which, combined with its structural stability, synergistically reduce resistance to lipid diffusion at the interface. Additionally, OCT-DEC significantly enhances the thermal stability of unsaturated fatty acids, such as C20:5, effectively preventing the degradation of high-value lipids and highlighting its potential for hydrothermal extraction of these valuable compounds.

Fast and green methodology based on miniaturised liquid–liquid extraction with a hydrophobic natural deep eutectic solvent of opium alkaloids from poppy seed beverages

Currently, the development of environmentally friendly analytical methodologies is a challenge for analytical chemistry. Therefore, the search for solvents to extract analytes of interest from complex matrices has progressed considerably in recent years. In the present work, 15 hydrophobic natural deep eutectic solvents (HNADES) consisting of a mixture of different donors and acceptors in different ratios have been prepared and compared to evaluate the most efficient extraction of opium alkaloids (OA) from fortified water samples. After selecting the most effective one consisting in a mixture of thymol and camphor in the ratio 1:1 ([Thy]:[Cam] 1:1), a rapid analytical methodology to determine OA in poppy seed beverages was optimised and validated for the first time. It was based on a miniaturised liquid–liquid extraction (m-LLE) with 0.5 mL of sample and 0.5 mL of HNADES by vortexing for 1 min, followed by 1 min centrifugation and subsequent analysis by high-performance liquid chromatography with diode array detector (HPLC-DAD). The validation was successful, showing extraction efficiencies between 91 and 107 % for all analytes, low limits of quantification (0.1 µg/mL for all analytes, except for morphine, 0.4 µg/mL) and precision values below 15 %. In addition, the greenness of the method was evaluated, obtaining a 0.79 on the AGREEprep metric scale. Therefore, it was demonstrated that the methodology developed to analyse OAs in poppy seed beverage was efficient, fast, simple and environmentally friendly.

Stability of Hydrophobic Deep Eutectic Solvents against Water

Stability of Hydrophobic Deep Eutectic Solvents against Water

Development of pH-Switchable Hydrophobic Deep Eutectic Solvents for the Extraction and Preconcentration of Aflatoxin M1 in Milk-Based Athlete Sports Supplements

Development of pH-Switchable Hydrophobic Deep Eutectic Solvents for the Extraction and Preconcentration of Aflatoxin M1 in Milk-Based Athlete Sports Supplements

Lipase Substrate Anchoring Dynamics Guided the Rational Design of Novel Deep Eutectic Solvents for Glucose Ester Synthesis.

Glucose esters, heralded for their emulsifying and solubilizing properties, have found increasing application in food, pharmaceutical, and cosmetic sectors. However, the environmental impact of chemical synthesis and the problem of enzyme inactivation in enzymatic synthesis have hindered their application. To this end, deep eutectic solvents (DESs) with stabilized enzyme activity and better solubility properties are considered a promising solution. In the study, 12 kinds of hydrophilic DESs and 22 kinds of hydrophobic DESs were screened, and we examined their efficiency in the synthesis of glucose esters. The results indicated that d,l-menthol-based DESs have excellent performance, with the highest yield of 92.85%. The molecular dynamics simulations suggested that it can be attributed to DESs changing the size of substrate binding pocket, which in turn affects the substrate anchoring ability and the catalytic efficiency of lipase. To further evaluate the effects of the solvent on the substrate anchoring ability of enzymes, a novel strategy, namely, substrate anchoring index, which is based on the stability of the tetrahedral intermediate, was proposed and used for the designing of more efficient DESs. Fortunately, novel DESs based on cyclohexanone (menthol analogues) were successfully developed with a yield of 98.85%.

A paradigm for natural eutectic solvents based on fatty acids: Molecular interactions and toxicological considerations

In this work, we present experimental and molecular modeling results on archetypal hydrophobic natural deep eutectic solvents (NADES) based on fatty acids (octanoic and dodecanoic acid) and menthol, a representative monoterpenoid. Our goal is to provide a multiscale characterization to enhance the understanding of this field by studying these selected archetypical mixtures. We examine their liquid state properties, intermolecular forces, nanoscopic arrangements, toxicity, and environmental impact.The computational study integrates quantum chemistry, molecular dynamics (both all-atom and coarse-grained approaches), and thermodynamic modeling (COSMO-RS approach) to analyze the fluids and their interactions with biological entities, such as proteins and plasma membranes. The experimental characterization focuses on elucidating intermolecular interactions and liquid phase dynamics using NMR spectroscopy, visible and UV Resonance Raman spectroscopy (UVRR). Notably, this is the first report of UVRR data on NADES.Additionally, we simulate the effect of the molecular moieties forming the solvents on biological targets—specifically, protein and cell membrane models –. This in silico analysis aims to rationalize and predict their potential toxicity.Overall, our experimental findings and in silico simulations contribute to a deeper understanding of these novel solvents in terms of their network of interactions. Additionally, they highlight the potential impact on biological targets, providing new data to accurately define the eco-friendliness of type V DES and their suitability as sustainable alternatives to traditional molecular solvents.

Medium/Long Chain Hydrophobic Deep Eutectic Solvent-Based Liquid Phase Microextraction for the Determination of Rhein, Emodin, and Chrysophanol with Detection by High-Performance Liquid Chromatography (HPLC)

Medium/long-chain fatty acids/alcohols as hydrogen bond donors coupled with methyltrioctylammonium chloride were used to prepare hydrophobic deep eutectic solvents (DESs) that were employed for the extraction of the anthraquinones (rhein, emodin, and chrysophanol) from fetal bovine serum. Hydrophobic DES-based liquid-phase microextraction and high-performance liquid chromatography were developed. The most suitable combination was optimized for liquid-phase microextraction. Spiked fetal bovine serum was analyzed with satisfactory extraction recoveries.

Preconcentration of Cinnamic Acid Derivatives in Traditional Chinese Medicines by an Effective Dispersive Liquid-Liquid Microextraction Based on a Hydrophobic Deep Eutectic Solvent.

A dispersive liquid-liquid microextraction based on hydrophobic deep eutectic solvent (hDES) was developed for the extraction and quantification of four cinnamic acid derivatives in traditional Chinese medicines coupled with high-performance liquid chromatography-ultraviolet detection. In this method, a hDES (tetrabutylammonium chloride-hexanoic acid, molar ratio of 1:2) was prepared as the extractant. It only took 15 s to handle multiple samples simultaneously by hand-assisted dispersion. The use of a narrow-bore tube reduced the amount of the hydrophobic extractant with easier recovery. The approach was influenced by several key parameters, including the composition and consumption of the DES, sample phase pH, salt amount, extraction time, and centrifugation time, all of which had been investigated and optimized. Moreover, the formation of the DES was characterized by Fourier-transform infrared spectroscopy and differential scanning calorimetry. Under the optimal conditions, enrichment factors of the target analytes ranged from 135 to 220. Satisfactory linearities (r ≥ 0.9977), detection limits (0.2-0.4ng/mL), precision (<8.5%), and accuracy (recoveries: 90.0%-104.6%) were obtained. The method has been successfully applied to the simultaneous extraction and preconcentration of four cinnamic acid derivatives in Chinese medicinal samples with rapidness, high efficiency, and convenience.

An emulsion extraction system composed of hydrophobic deep eutectic solvent and water for synchronous extraction of oil and phenolic compounds from U.S. pecans [Carya illinoinensis (Wangenh.) K. Koch]

U.S. pecans nuts are rich in oils and phenolic compounds with important biological functions. At present, the reports about simultaneous extraction of oil and phenolic compounds are limited, and the traditional procedure is complicated and the yield is low. In this study, a new emulsion formed by hydrophobic deep eutectic solvent (DES) and water was used as extractant for synchronous extraction of oil and phenolic components from U.S. pecans, and subsequently the two were recovered from the upper and lower phases based on the incompatibility of DES and water, respectively. The oil and phenolic compounds obtained by the optimization of extraction conditions were 615.29 mg/g and 82.11 mg/g, respectively, which were higher than those obtained by conventional methods. At the same time, the extraction mechanism is discussed through the extraction kinetics and thermodynamics. The extraction process conformed to the Fick’s second law, and it was an endothermic process. After directional recovery by macroporous resin and back-extraction, the effectiveness of the method was proved by the analysis of fatty acid composition of oil, spectral characterization of phenolic compounds and antioxidant activities.

In silico study on helicenes in hydrophobic natural deep eutectic solvent

This research explores the behavior of helicenes in Deep Eutectic Solvents (DES) formed by thymol and dodecanoic acid using a combined theoretical approach. COSMOtherm, Density Functional Theory (DFT), and molecular dynamics (MD) simulations were employed to elucidate the interactions between helicenes and the DES components at the molecular level. The behavior of helicenes in water was also studied as a reference system. COSMOtherm calculations provided insights into the thermodynamic properties of the system. DFT simulations allowed for the investigation of the electronic structure and bonding interactions between helicenes and DES molecules. Additionally, MD simulations offered dynamic information on the solvation behavior and conformational preferences of helicenes within the DES media. The combined approach provides a comprehensive understanding of the interactions between helicenes and thymol-dodecanoic acid DES. The research findings will contribute to the development of a theoretical framework for predicting the behavior of other functional molecules in DES environments. This knowledge has potential applications in various fields, including material science, catalysis, and drug delivery.

Formulation and Characterization of Deep Eutectic Solvents and Potential Application in Recycling Packaging Laminates.

Deep Eutectic Solvents (DESs) show promising abilities for the delamination of multilayer packaging films that are used in food packaging and in pharmaceutical blister packs. Due to the complexity of their structure, the recycling of such materials is a challenging task, leading to the easiest or cheapest disposal option of either landfill or incineration. Towards the development of 'green' solvents for efficient waste management and recycling, this research focuses on the preparation of a range of hydrophobic and hydrophilic DESs based on carboxylic acids in combination with various naturally derived aliphatic and aromatic organic compounds as well as amino acids. Chemical and physical characterization of the solvents was undertaken using differential scanning calorimetry, rheometry, and density measurements for the determination of their properties. Subsequently, batches of solvent were tested against different types of consumer packaging to evaluate the ability of the DES to delaminate these structures into their component materials. The laminate packaging waste products tested were Al/PE, PE/Al/PET, Al/PE/paper, and PVC/PE/Al. Separated films were collected and studied to further examine the effect of solvent delamination on the materials. Depending on the DES formulation, the results showed either partial or full delamination of one or more of the packaging materials, albeit there were challenges for certain solvent systems in the context of delivering a broad delamination efficiency. Variables including temperature, agitation rate, mixing time, and solvent ratios were investigated via a Design of Experiments process to assess the effects of these parameters on the delamination outcome. The results showed that the DESs presented in this research can offer an efficient, low-energy, affordable, and green option for the delamination of laminate packaging materials.

Delamination and Evaluation of Multilayer PE/Al/PET Packaging Waste Separated Using a Hydrophobic Deep Eutectic Solvent.

This research concerns the development and implementation of ground-breaking strategies for improving the sorting, separation, and recycling of common flexible laminate packaging materials. Such packaging laminates incorporate different functional materials in order to achieve the desired mechanical performance and barrier properties. Common components include poly(ethylene) (PE), poly(propylene) (PP), and poly(ethylene terephthalate) (PET), as well as valuable barrier materials such as poly(vinyl alcohol) (PVOH) and aluminium (Al) foils. Although widely used for the protection and preservation of food produce, such packaging materials present significant challenges for established recycling infrastructure and, therefore, to our future ambitions for a circular economy. Experience from the field of ionic liquids (ILs) and deep eutectic solvents (DESs) has been leveraged to develop novel green solvent systems that delaminate multilayer packaging materials to facilitate the separation and recovery of high-purity commodity plastics and aluminium. This research focuses on the development of a hydrophobic DES and the application of a Design of Experiments (DoE) methodology to investigate the effects of process parameters on the delamination of PE/Al/PET laminate packaging films. Key variables including temperature, time, loading, flake size, and perforations were assessed at laboratory scale using a 1 L filter reactor vessel. The results demonstrate that efficient separation of PE, Al, and PET can be achieved with high yields for material and solvent recovery. Recovered plastic films were subsequently characterised via Fourier-transform infra-red (FTIR) spectroscopy, Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA) to qualify the quality of plastics for reuse.

Investigating the Use of Natural Hydrophobic Deep Eutectic Solvents for Extracting Carotenoids from Food and Food By-products

Abstract In today’s food industry, the demand for sustainable methodologies in producing health-promoting natural products is rising. Traditional extraction techniques are increasingly deemed unreliable due to environmental concerns. To address these challenges, the scientific community has developed Green Chemistry , a specialized branch that aims to minimize or eliminate hazardous processes and substances in industrial applications. One promising and eco-friendly alternative emerging from Green Chemistry is the use of NaDESs which are prepared with natural components, generally recognized as safe (GRAS), and offer an environmentally benign option for various industrial processes. They are characterized by their biodegradability, low toxicity, and ability to be tailored for specific applications, making them an ideal choice for green extraction methods. In this context, NaHDESs have shown significant potential as extracting media for bioactive compounds, particularly carotenoids, from food and food by-products. Carotenoids, known for their antioxidant properties and health benefits, are highly sought after in the food and nutraceutical industries. Traditional extraction methods often rely on organic solvents, which pose environmental and health risks. In contrast, NaHDESs offer a safer and more sustainable alternative. This study explores the definition, properties, and applications of NaHDESs, with a particular focus on their use in extracting carotenoids. By examining various food and vegetable by-products, the research aims to evaluate the solvent’s efficiency and effectiveness in this application. The findings could pave the way for eco-friendly extraction techniques in the food industry, aligning with the principles of Green Chemistry and addressing the growing demand for natural and health-promoting products. Information © The Author 2024

Extraction of phenolic acids and tetramethylpyrazine in Shanxi aged vinegar base on vortex-assisted liquid-liquid microextraction-hydrophobic deep eutectic solvent: COSMO-RS calculations and ANN-GA optimization

In this study, vortex-assisted liquid-liquid microextraction (VA-LLME) based on hydrophobic deep eutectic solvents (HDES) was used to efficiently and sustainably extract five phenolic acids and tetramethylpyrazine (TMP) from Shanxi aged vinegar (SAV). The VA-LLME technique was employed to investigate the extraction mechanism of HDES with the best extraction performance for the target compounds using a conductor-like screening model for real solvents (COSMO-RS). An artificial neural network combined with a genetic algorithm (ANN-GA) was developed to optimize the extraction conditions based on single-factor and response surface methodology, while also analyzing the interactive effects on the phenolic acids and TMP in the extracted solution during the extraction phase. The optimized conditions were determined, and the greenness of the procedure was evaluated using an analytical greenness metric, indicating that this technique can serve as a green alternative for the determination of phenolic acids and TMP in SAV.

A conductive ionogel with Stretchability, low hysteresis and adjustable adhesion for Air/Underwater mechanosensing

Conductive ionogels based on deep eutectic solvents (DESs) have great application potential in the field of flexible sensors. However, the development of conductive ionogels that are stable under various environmental conditions (such as high and low temperatures, air, and water) remains extremely challenging. In this work, the hydrophobic conductive ionogel BxHyIG was prepared via a one-step photoinitiated copolymerization of butyl acrylate and N-hydroxyethylacrylamide in a hydrophobic DES. The good chemical compatibility between the polymer and DES, as well as the dense and reversible ion–dipole interactions, dipole–dipole interactions and hydrogen bond interactions, endow BxHyIG with satisfactory transparency (80 %), adhesion (polystyrene: 74.56 kPa), mechanical properties (elongation at break: 578 %, tensile strength: 171.25 kPa), a low degree of hysteresis (DH=1.9 %) and conductivity (3.95 × 10-3 S m−1). Strain/pressure sensors and bioelectrodes prepared from ionogels have the characteristics of high sensitivity, fast response and excellent stability and can be used for real-time monitoring of human activities and health status in the atmosphere. In addition, the inherent hydrophobicity of BxHyIG (water contact angle > 110°) can effectively prevent BxHyIG from being eroded and swollen by water, thereby achieving reliable underwater sensing. More importantly, by directly exposing BxHyIG to air or storing it in nitrogen, the surface adhesion of conductive ionogels can be effectively regulated to obtain double-sided, single-sided or even nonadhesive ionogels. Therefore, this study provides new ideas for the development of conductive ionogels that can be applied under various environmental conditions.

Advances in Sustainable Extraction of Arsenic and Cadmium from Sewage Sludge: Use of Hydrophobic Deep Eutectic Solvent Modified with Magnetic Nanoparticles

Advances in Sustainable Extraction of Arsenic and Cadmium from Sewage Sludge: Use of Hydrophobic Deep Eutectic Solvent Modified with Magnetic Nanoparticles

Optimizing carotenoids NaHDES extraction for enhancing spreadable chocolate's nutritional value

The potential to directly fortify food products using extracts obtained through green solvents is both innovative and promising. In pursuit of this goal, this study evaluated the possibility of directly fortifying spreadable chocolate with an optimized carotenoid-rich Natural Hydrophobic Deep Eutectic Solvent (NaHDES) extract formulated with monoterpenes. The optimized extract (3.545 ± 0.126, 3.341 ± 0.023, and 0.049 ± 0.001 mg/mL for total carotenoids, β-carotene and lutein, respectively) was obtained using a thymol/DL-menthol molar ratio of 1:4, a solvent:sample ratio of 10 (v/w), and an extraction time of 30 min. Subsequently, commercial no-sugar-added spreadable chocolate was fortified with the selected extract at 14 and 28 % (v/w). The fortified products were analyzed for carotenoid content, antioxidant activity, physicochemical and textural properties. The findings revealed that the lower extract addition minimally impacts the investigated characteristics of spreadable chocolate. Considering the preserving effect of the selected NaHDES on carotenoids and antioxidant activity, this innovative approach holds great promise for enhancing fortified food products' nutritional value and stability.