Hydrophobic Solvents Research Articles

Hydrophobic deep eutectic solvent-ferrofluid microextraction followed by liquid chromatography-mass spectrometry for the enantioselective determination of chiral agrochemicals in natural waters.

The increasing use of chiral agrochemicals sold as racemic formulations raises concern for the negative impacts that inactive enantiomers can have on aquatic life and human health. The present work just focuses on the determination of ten chiral pesticides in river water samples by applying a ferrofluid-based microextraction followed by their stereoselective liquid chromatography analysis. To develop the ferrofluid, magnetite nanoparticles were prepared and coated with oleic acid and then dispersed in a hydrophobic natural deep eutectic solvent (NaDES), composed ofL-menthol and thymol (1:1). The stable colloidal dispersion was characterised by scanning electron microscopy, thermogravimetric analysis, energy-dispersive X-ray spectroscopy and attenuated total reflection Fourier transform infrared spectroscopy. The analyte microextraction from 5ml river samples was performed using 50µl of ferrofluid, while acidified acetonitrile (150µl) was used to break down the ferrofluid and solubilise the NaDES containing the analytes. All the extracts were analysed by high-performance liquid chromatography-tandem mass spectrometry. For each analyte, the baseline separation of isomers was achieved on a Lux i-Amylose-3 column (amylose tris(3-chloro-5-methylphenylcarbamate) working in reversed-phase mode; the combination with mass spectrometry detection allows the overall separation of 24 isomers (ten chiral analytes among which eight containing a single (one) chiral centre, one with two chiral centres and the last one existing in four stereoisomeric forms, due to the presence of two regioisomers with a chiral carbon) within 37min. The method showed very good figures of merit in terms of recoveries (77.7-97.5%), intra-day and inter-day precision (2.7-7.7% and 6.9-14.9%, respectively), limit of detection (0.01-0.35µg/L), limit of quantitation (0.03-1.20µg/L), linear dynamic range, and intra-day and inter-day accuracy (1.2-14.8% and 1.8-15.0%, respectively). The presented method was able to detect 14 out of 24 isomers at the preventive limit established by the Italian legislation for single pesticide (that for a chiral pesticide is the sum of all its isomers) in surface waters, set at 0.1µg/l. Finally, the method was evaluated using AGREEprep and ComplexGAPI metrics, compared with other ferrofluid-based methods, and applied to the analysis of water samples from two Italian rivers (the Nera River and the Tiber River), providing to be sustainable and reliable for the application to real river matrices.

Eutectic Strategy for the Solvent-Free Synthesis of Hydrophobic Cellulosic Cross-Linked Networks with Broad Multifunctional Applications.

Cellulose-based functional materials play a crucial role in sustainable social development. However, during the material synthesis process, there is typically significant reliance on various solvent systems for macroscopic- or molecular-scale functionalization modifications. In this study, an innovative hydrophobic eutectic solvent (HES) was developed using ethyl cellulose (EC) and thymol (Thy) without any external solvents. Utilizing this homogeneous system, it is convenient to chemically modify the components without any catalyst. Furthermore, a hydrophobic cellulosic cross-linked network (HCCN) can be successfully prepared through in situ photopolymerization. The HCCN film exhibits high transparency, excellent mechanical properties, chemical stability, and durability. The EC/Thy prepolymer system also demonstrates favorable processability for the preparation of various polymeric materials. Additionally, the applicability of other biomasses and derivatives based on the eutectic strategy has been verified. The methodology proposed in this study offers novel insights into the green and solvent-free preparation of biomass functional materials.

Extraction of mucilage polysaccharides from chia seed by hydrophobic deep eutectic solvents-based three-phase partitioning system: A phase behavior-driven approach

By incorporating the hydrophobic deep eutectic solvents (DESs) into the three-phase partitioning (TPP) technique, a TPP-based method was developed to extract the chia seed polysaccharide (CSP) from chia seed. Through a single-factor experiment and response-surface model, the optimal condition for the TPP extraction was determined as DES composed of dodecanoic acid and octanoic acid in a 1:1 M ratio, (NH4)2SO4 concentration of 32.86 %, crude extract–DES ratio of 0.93 (v/v), aqueous phase pH of 4.38, extraction temperature of 35 °C, and extraction time of 10 min. The polysaccharide yield of the constructed TPP method is 8.65 %, which is higher than the conventional water extraction method (yield is 6.96 %). Molecular dynamics simulations reveal the phase behavior of proteins and polysaccharides in the TPP system, showing that noncovalent interactions play a crucial role in the TPP system. The CSP obtained by the TPP method exhibits distinctive composition, structural, physicochemical, and functional properties, leading to improved thermal stability, rheological behavior, and antioxidant performance. Compared with the traditional extraction method, efficient extraction of CSP can be achieved flexibly using the proposed TPP approach, resulting in high yield and quality of CSP, which provides a new path for the large-scale utilization of chia seed.

Determination of parabens and bisphenol A in sludge samples using hydrophobic deep eutectic solvents by gas chromatography coupled to mass spectrometry and sample introduction via pyrolizer

Determination of parabens and bisphenol A in sludge samples using hydrophobic deep eutectic solvents by gas chromatography coupled to mass spectrometry and sample introduction via pyrolizer

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.

Pathogenic Mutation ΔK280 Promotes Hydrophobic Interactions Involving Microtubule-Binding Domain and Enhances Liquid-Liquid Phase Separation of Tau.

Liquid-liquid phase separation (LLPS) of tau protein can initiate its aggregation which is associated with Alzheimer's disease. The pathogenic mutation ΔK280 can enhance the aggregation of K18, a truncated tau variant comprising the microtubule-binding domain. However, the impact of ΔK280 on K18 LLPS and underlying mechanisms are largely unexplored. Herein, the conformational ensemble and LLPS of ΔK280 K18 through multiscale molecular simulations and microscopy experiments are investigated. All-atom molecular dynamic simulations reveal that ΔK280 significantly enhances the collapse degree and β-sheet content of the K18 monomer, indicating that ΔK280 mutation may promote K18 LLPS, validated by coarse-grained phase-coexistence simulations and microscopy experiments. Importantly, ΔK280 mutation promotes β-sheet formation of six motifs (especially PHF6), increases the hydrophobic solvent exposure of PHF6* and PHF6, and enhances hydrophobic, hydrogen bonding, and cation-π interactions involving most of the motifs, thus facilitating the phase separation of K18. Notably, ΔK280 alters the interaction network among the six motifs, inducing the formation of K18 conformations with high β-sheet contents and collapse degree. Coarse-grained simulations on full-length tau reveal that ΔK280 promotes tau LLPS by enhancing the hydrophobic interactions involving the microtubule-binding domain. These findings offer detailed mechanistic insights into ΔK280-induced tau pathogenesis, providing potential targets for therapeutic intervention.

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

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.

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.

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.

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.

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.

Ultra-sensitive CO2 switchable low temperature transition mixture for intensified retrieval of oily waste

One of the challenge in the remediation of contaminated soil by solvent washing is the retrieval of total petroleum hydrocarbons (TPH) and solvents. Herein, a CO2 switchable hydrophobic low temperature transition mixture ([DPA][EL]) composed of ethyl lactate (EL) and dipropylamine (DPA) is proposed, accompanied by a proof-of-concept for contaminated soil washing. The path and energy of hydrogen bond interactions in [DPA][EL] were revealed by the quantum chemical calculation using the quantum theory of atoms in molecule. [DPA][EL] achieved a thorough CO2-induced polarity and hydrophobicity transition undergoing an incomplete CO2 absorption that results in the partial formation of carbonate and carbamate. [DPA][EL] was regenerated after the removal of CO2 by heating at 85 °C for 2 min. Thanks to this peculiarity, the time required for hydrophobicity transition was 197 times shorter than that of the typical CO2 switchable hydrophobic solvent, N,N-dimethylcyclohexylamine. The polarity of [DPA][EL], quantified by the normalized polarity energy, increased by 346.69 % after the introduction of CO2 because of the synergistic effect of water. This ultra-sensitive transition behavior intensified the CO2-induced separation of oily compounds, e.g., kerosene and crude oil. The conceptual usage of [DPA][EL] in the contaminated soil washing was demonstrated. The TPH content of contaminated soil decrease from 8.27 % to 0.31 % by [DPA][EL] washing through tailoring the molar ratio of DPA to EL in [DPA][EL], temperature, and [DPA][EL] to contaminated soil ratio (L/S, mL/g). [DPA][EL] whose composition possesses different polarities compensated for the poor solubility of single solvents towards TPH, thereby improving the washing efficiency of contaminated soil. Afterwards, TPH was separated upon triggered by CO2/water in 2 min, and 91.33 % of [DPA][EL] was subsequently regenerated at 85 °C in 2 min.

Synthesis and electric field response of titanium dioxide nano-particles dispersed in hydrophobic solvents.

We present a novel synthesis method for producing stable titanium dioxide nanoparticles (<10 nm) dispersed in hydrophobic solvents using organophosphates. Our approach enables the control of nanoparticles' electric field responsiveness by altering the dispersing medium's composition, expanding their potential applications in electronics, photovoltaics, and photocatalysis.

Enhanced furfural extraction using neoteric hydrophobic solvents for sustainable biomass recovery and bioenergy applications

The recovery of furfural from hemicellulosic biowastes is important for developing sustainable and renewable energy alternatives to fossil fuels. However, current methods are inefficient and environmentally questionable. To address this issue, this study introduces neoteric hydrophobic solvents, specifically deep eutectic solvents (DESs) and ionic liquids (ILs). Of the 32 solvents tested, thymol:decanoic acid 1:1 (Thy:DecA) DES and trihexyltetradecyl phosphonium bis(trifluoro methylsulfonyl) imide [P14,6,6,6][NTf2] IL were the most effective, with extraction efficiencies of 94.1% and 97.1%, respectively. These solvents outperformed the reference solvent toluene, with an efficiency of 81.2%, while also showing favorable characteristics in multiple investigated criterions. For the first time, excellent performance stability was demonstrated under various operational conditions and reusability over multiple extraction and regeneration cycles. Furthermore, to provide insights into the molecular mechanisms of extraction, computational quantum chemistry modeling was employed, which showed a strong agreement with the experimental results. The development of these new neoteric solvents for furfural recovery from biowaste offers a highly effective, sustainable, and eco-friendly alternative to traditional solvents, representing a significant breakthrough in the field of renewable bioenergy production and sustainable materials recovery.