Hydrophilic Solvents Research Articles

Comparing the improvement of enzymatic hydrolysis effect of Celtis sinensis leaves residue by hydrophilic or hydrophobic deep eutectic solvent pretreatment

Comparing the improvement of enzymatic hydrolysis effect of Celtis sinensis leaves residue by hydrophilic or hydrophobic deep eutectic solvent pretreatment

Structural characterization and physicochemical properties of different hydrophilic natural deep eutectic solvents.

To overcome the toxic nature of organic solvents, scientific interest in the use of green solvents, particularly natural deep eutectic solvents (NADES), has increased over the past decade, leading to new applications in the food, nutraceutical, pharmaceutical, and cosmetic industries. Understanding the physicochemical properties and molecular interactions of NADES is essential for uncovering new potential applications in these fields. In this study, several lactic and citric acid-based NADES, as well as chloride choline- and urea-based NADES, were evaluated for their physicochemical properties, including density, pH, viscosity, conductivity, and refractive index. Additionally, nuclear magnetic resonance (NMR), and in particular nuclear Overhauser enhancement spectroscopy (NOESY), was employed to investigate the intermolecular interactions between the NADES components to confirm the formation of the eutectic mixture. The extraction efficiency of the confirmed NADES was tested for extracting polyphenols as a proof of concept to highlight their relationship with the measured properties. Lactic and choline chloride-based NADES provided the highest extraction yields. These results were also compared with the predicted extraction capabilities of each NADES provided by the COSMO-RS software.

Four-liquid-phase system for simultaneous extraction and separation method of various active components in Antarctic krill crude oil extract

A four-liquid-phase system (FLPS) was serendipitously discovered when appropriate amounts of Antarctic krill crude oil extract (AKCOE), salt, water, a hydrophilic solvent, and a hydrophobic solvent were mixed. The system contained two hydrophobic phases and two hydrophilic phases, so the four main components of AKCOE (astaxanthin, phospholipids, proteins, and saccharides) could be simultaneously extracted into the various phases in a single step. For example, in a Na2CO3/ethanol/isooctane FLPS, 97.53% of phospholipids (the most important components) partitioned into the weakly hydrophobic phase, and astaxanthin, proteins, and saccharides simultaneously separated into the other three phases, with high yields (approximately 80%). Furthermore, the AKCOE phospholipids have been demonstrated to be key factors in FLPS formation, which provides an important reference for future designs of new FLPSs. This novel method is simple to operate and has the potential to scale-up; therefore, it may serve as a simple and efficient method for the separation and purification of biological mixtures containing many different polar components.

An eco-friendly strategy for emerging contaminants removal in water: Study of the adsorption properties and kinetics of self-polymerized PHEMA in green solvents

Water contaminants severely affect human health and aquatic ecosystems, and adsorption poses an economic, available, and feasible technology for remediation that needs to be accompanied by eco-friendly and sustainable materials. This study proposes an eco-friendly strategy for removing emerging contaminants using polyhydroxyethyl methacrylate polymers synthesized by self-polymerization with hydrophilic first-generation deep eutectic solvents. The polymers were characterized using structural and physical characterization techniques and their adsorption capacity against four emerging contaminants: a non-steroidal anti-inflammatory drug, an antibiotic, a pesticide, and a non-ionic surfactant. The experimental results showed high adsorption capacity for the urea: choline chloride-derived polymer with 6.21, 7.19, 6.01, and 6.99 mg⋅g-1 for paracetamol, ciprofloxacin, glyphosate, and triton X-100, respectively; these values are comparable to those obtained for similar systems. Kinetic, isothermal, and thermodynamics were also studied using various mathematical models to understand the adsorption mechanism, further complemented by DFT analysis. Chemisorption was found to be the primary mechanism by exothermic and ordered processes, which is thermodynamically favored. The study demonstrated for the first-time the effectiveness of self-polymerized PHEMA without chemical modification as a reusable adsorbent material and its ability to remove different types of emerging contaminants, thereby offering a promising solution for water treatment in environmental science.

Effervescent-assisted Liquid-phase Microextraction Employing Switchable Hydrophilicity Solvent for the Determination of Cortisol and Testosterone in Oral Fluid by High-Performance Liquid Chromatography-Diode Array Detection.

Cortisol and testosterone are important biomarkers for diagnosing complex disorders, including polycystic ovary syndrome and Cushing's syndrome, where symptomatology usually overlaps with other prevalent disorders. This work proposes, for the first time, an analytical method based on a switchable hydrophilicity solvent as an extraction phase for the determination of cortisol and testosterone in oral fluid (OF) by high-performance liquid chromatography with diode-array detection. The optimized extraction conditions consisted of 1000µL of OF, 100µL of decanoic acid solution (65mg/mL), 170µL of Na2CO3, 900µL of H2SO4 and 150µL of acetonitrile for dilution. The method was validated, and coefficients of determination higher than 0.9926, the limit of detection of 4.55ng/mL and the limit of quantification of 15.00ng/mL were obtained. Intra-day precision varied from 5.6% to 11.9%, inter-day precision ranged from 6.1% to 13.5%, and relative recoveries ranged from 98.9% to 104.6% for cortisol, and 89.1% to 103.9% for testosterone. This methodology was successfully applied to five OF samples from volunteers. Moreover, the greenness of this methodology was evaluated based on the sample preparation metric of sustainability achieving a global score of 7.37 which can be considered sustainable.

Review article on self emulsifying system

The solubility challenges faced by the pharmaceutical industry, particularly with orally administered drugs, are indeed significant. Low aqueous solubility often leads to poor dissolution and subsequently, low bioavailability, which can result in inconsistent drug effects among patients. Various methods have been explored to address this issue, including salt formation, solid dispersion, and complex formation.Among these approaches, Self-Emulsifying Drug Delivery Systems (SEDDS) have emerged as a promising solution for enhancing the solubility of lipophilic drugs. SEDDS consist of isotropic mixtures of hydrophilic solvents, co-solvents, and surfactants. They possess the unique ability to form fine oil-in-water micro emulsions upon mild agitation and dilution in aqueous media, such as gastrointestinal fluids.The advancement in SEDDS technology encompasses improvements in composition, evaluation methods, development of different dosage forms, and techniques for converting liquid SEDDS into solid forms. These advancements not only enhance solubility but also offer versatility in administration routes and dosage forms, thereby expanding the potential applications of SEDDS in pharmaceutical formulations.This comprehensive review provides valuable insights into the latest developments in SEDDS, offering a detailed account of its composition, evaluation parameters, diverse dosage forms, and innovative techniques for solidification. Moreover, it highlights the diverse applications of SEDDS across various therapeutic areas, underscoring its growing significance in modern pharmaceutical research and development.

A novel green cloud point extraction-based switchable hydrophilicity solvent method for antimony separation and quantification from various bottled beverages by HGAAS

Herein, switchable hydrophilicity solvent (SHS) was used as a synergistic reagent in the cloud point extraction (CPE) protocol to increase the procedure’s efficiency and sensitivity. At room temperature, the CPE-SHS method was created for the fast and accurate extraction of antimony from a variety of drinks. Hydride generation atomic absorption spectroscopy (HGAAS) was used to antimony detection in various samples following the CPE-SHS protocol. The N,N-dimethylamine (DMA), TritonX-100, and p-tert-butyl-tetrakis[(diethylamide)methoxy]tetrathiacalix[4]arene (BTDMTA) were used as a SHS, surfactant, and chelation reagent, respectively. This procedure’s criteria for validation have been identified, including linearity (0.01–700 µg/L), accuracy, precision, limit of detection (LOD = 0.007 µg/L), limit of quantification (LOQ = 0.023 µg/L), enhancement factor (EF = 160), and matrix influence. This approach was validated using certified reference material. The environmentally friendly practices of this method were assessed using recent tools like Complex Modified GAPI (ComplexMoGAPI) software, Analytical GREEnness Calculator (AGREE) software, Blue Applicability Grade Index (BAGI) software, and Sample Preparation Metric of Sustainability (SPMS) program.

In-situ preparation of lanthanide luminescent MOF hydrogel for aldehyde detection☆

Metal-organic frameworks (MOFs) usually exist in the state of powder or crystal. When they are exposed to hydrophilic solvents, their structure will change and become unstable. Therefore, it is a challenge to construct MOF materials with tunable mechanical properties. Herein, we report in-situ growth lanthanide metal-organic framework (LnMOF) in sodium alginate (SA) and polyvinyl alcohol (PVA) hydrogel matrix. The prepared composite hydrogel not only displays characteristic lanthanide narrow-band emission under ultraviolet light, but also demonstrates excellent mechanical properties. The addition of LnMOF significantly enhances the compressive strength of the hydrogel (from 0.75 to 7.32 MPa). Furthermore, the composite hydrogel shows highly selective recognition of glutaraldehyde and gaseous formaldehyde at room temperature. The detection limits (LOD) of SP-EuMOF for glutaraldehyde and formaldehyde are 0.27 and 0.22 ppm, respectively. Based on these results, the LnMOF composite hydrogel is deemed to have significant potential as a fluorescent sensor for both glutaraldehyde and formaldehyde detection.

Wetting mechanism and alteration of nano-sized shale pores: Insights from contrast variation small angle neutron scattering

Wettability of tight shale is crucial for fluid flow and mass transport process in energy geosciences. However, understanding the interfacial chemistry and wetting mechanisms at sub-nano-pore scales remains a formidable challenge. In this study, the Contrast Variation technique of Small Angle Neutron Scattering (CV-SANS) is employed to investigate shale’s interfacial chemistry using reagents that possess a range of different polarities, including water, n-decane, toluene, and dimethyl methanamide. Through five different experimental strategies, we have demonstrated a successful modification of shale wettability, ranging from enhancement, weakening, to reversal. Delving into the mechanisms, we illustrated the crucial role of pre-existing liquid films in these changes, where the uniquely co-existing polar and non-polar functional groups in dimethyl methanamide acted as a conduit for interfacial chemistry adjustments. Furthermore, a solvent immersion led to matrix dilation as well as liberation of residual oil-occupied pores, resulting in altered pore size distributions, with hydrogen bonding playing a significant role in the polar groups. Interestingly, despite shale exhibiting a stronger affinity for oil over water, hydrophilic solvents induced more substantial dilation than lipophilic ones. Collectively, this work elucidates the dynamic change of interfacial chemistry via the configuration of polarity using chemical reagents, and the CV-SANS technique underscores its invaluable utilities in decoding the interfacial wettability traits in nanopore space of shale.

A novel temperature-responsive biphasic deep eutectic solvent-based solvent system: Integrated efficient extraction, enrichment and recovery of phytochemicals

The current large-scale use of organic and some toxic reagents hinders the development of plant secondary metabolite extraction and processing industry. Here, a biphasic temperature-responsive solvent system consisting of hydrophilic deep eutectic solvent (choline chloride: levulinic acid) and fatty acid-based hydrophobic deep eutectic solvent is developed. Some characteristics of this intelligent solvent system, including hundreds of synthesis ratios and corresponding switching temperatures, phase ratios, etc., have been comprehensively determined. Subsequently, it is applied to different plant matrices. The extraction efficiencies ranged from 1.006 to 6.807 times higher than those of conventional organic reagents, with separation efficiencies ranging from 60.7 % to 100 %, besides the fact that the hydrophilic components are almost entirely distributed in the lower phase. The recovery of targeted phytochemicals achieves satisfactory results during the simultaneous extraction and enrichment process. Mechanisms of switching, extraction, and enrichment have been elucidated to a certain extent from the point of view of chemical computational simulations. Overall, this new green solvent system is universal and can be applied to a wide range of phytochemicals extraction and separation from plants in a one-pot operating unit. Also, it is almost the greenest of the temperature-responsive solvents studied so far and has superior application prospects.

A recoverable hydrophilic deep eutectic solvent for efficient extraction of polyphenolic compounds from raspberry root.

Green deep eutectic solvents (DESs) are widely used to extract bioactive components from plant biomass; however, hydrophilic DES and bioactive component isolation methods have not been developed. In this study, we synthesized hydrophilic DES (CL-CA-DES) using citric acid and choline chloride. We combined this with environmentally friendly anion- and cation-exchange resin column chromatographic isolation methods. This approach extracted and isolated four polyphenolic compounds (catechins, epicatechins, procyanidin B1, and procyanidin B2) from raspberry root and efficiently recovered the hydrophilic DES. CL-CA-DES extracted significantly higher contents of catechin and procyanidin B2 from raspberry root compared to other solvents. It also extracted substantially higher contents of epicatechin compared to butyl alcohol, 70% ethanol, and water, but there was no significant difference when compared with acetone and ethyl acetate. Additionally, CL-CA-DES extracted significantly higher contents of procyanidin B1 compared to butyl alcohol, water, and ethyl acetate, with no significant difference when compared with 70% ethanol and acetone. The isolation efficiency of the bioactive components in the raspberry root extract by anion- and cation-exchange resin column chromatography was higher than that of the organic solvent extraction and precipitation generation methods, and the method was effective in recovering CL-CA-DES with a recovery rate higher than 60%. In conclusion, this study developed a new method for the efficient recovery of hydrophilic CL-CA-DES, which can be used for isolating polyphenolic compounds from raspberry root.

Exchange of Thiol Ligands on CuInS2 Quantum Dots in High Boiling Solvents.

As-prepared quantum dots are covered with long-chain ligands to prevent aggregation. When quantum dots are used in optoelectronic devices such as solar cells and QD-LED, ligand exchange is necessary to replace long-chain ligands with short-chain ones to increase the efficiency of charge transfer from the quantum dots to the electrode. In this study, we successfully exchanged 1-dodecanethiol (DDT) ligands on CuInS2 quantum dots with mercaptopropionic acid (MPA) ligands by using a two-phase system of high-boiling hydrophilic and hydrophobic solvents. The ligand exchange to MPA was achieved by using diethylene glycol (DEG) or ethylene glycol (EG) as the hydrophilic phase and tetradecane as the hydrophobic phase. The ligand exchange rate increased with increasing ligand exchange temperature. When quantum dot sensitized solar cells (QDSSCs) were fabricated using the ligand-exchanged quantum dots, a positive correlation was observed between the progress of ligand exchange and short-circuit current density. This is because charge transfer efficiency from the quantum dots to the TiO2 electrode was improved by the ligand exchange. This work has shown that QDs synthesized using DDT can be applied to optoelectronic devices.

Enhancing flexibility and durability of PVC with liquid epoxidized natural rubber: Innovative UV treatment to mitigate plasticizer migration

AbstractThis manuscript elucidates the preparation and utilization of liquid epoxidized natural rubber (LENR) with 50 mol% epoxidation level (LENR50) as a polymeric plasticizer for poly(vinyl chloride) (PVC), and further immobilization of the plasticizer in the plastic matrix through subsequent ultraviolet (UV)‐curing treatment. The plasticizing effect induced by LENR50 at 50 wt% loading was evident with a reduction of Tg from a high of 72.0 to 11.4°C. Positive enhancements were also documented in the mechanical properties of the LENR50‐plasticized PVC, specifically the big improvement in elongation at break and elastic modulus, from 106% to 430%, and from 646 to 7 MPa, respectively. The UV‐treated PVC/LENR film also exhibited superior resistance to migration compared with formulations with conventional plasticizers such as di‐2‐ethylhexyl phthalate (DEHP) and triethyl‐2‐acetyl citrate (ATEC). A similar outcome was recorded in the leaching resistance test, where LENR50 had the best resistance to leaching in four different solvents (water, soap solution, ethanol, and toluene). The LENR50‐plasticized PVC film recorded the lowest weight loss following 24 h immersion in both hydrophilic and lipophilic solvents. The findings from this study suggest that LENR50 could serve as an efficient bio‐based polymeric plasticizer for PVC.Highlights LENR as bio‐based polymeric plasticizer for PVC. Significant reduction in Tg and elastic modulus of PVC plasticized with LENR. UV treatment improved tensile strength and elongation at break of LENR/PVC film. UV‐treated PVC/LENR has superior plasticizer migration and leaching resistance.

Liquid–liquid microextraction method based on switchable hydrophilic solvent for determination of parabens in cream samples

Liquid–liquid microextraction method based on switchable hydrophilic solvent for determination of parabens in cream samples

A Novel DLLME Method Involving a Solidifying Hydrophobic Deep Eutectic Solvent Using Hydrophilic Deep Eutectic Solvent as the Dispersant for the Determination of Polychlorinated Biphenyls in Water Samples.

This paper presents a novel dispersive liquid-liquid microextraction (DLLME) method that employs solidified hydrophobic deep eutectic solvent (DES) with hydrophilic DES acting as the dispersant. The aim is to enrich polychlorinated biphenyls (PCBs) from water samples for subsequent determination by gas chromatography-mass spectrometry. The effects of both the hydrophobic DES as the extractant and the hydrophilic DES as the dispersant were thoroughly investigated. Optimization of the key factors influencing extraction efficiency was performed, and the method was subsequently validated. Specifically, a hydrophobic DES called DES2, prepared by combining thymol and decanoic acid in a molar ratio of 3:2, was selected as the extraction solvent. Meanwhile, a hydrophilic DES named DES6, prepared from choline chloride and acetic acid in a molar ratio of 1:2, was chosen as a dispersant. Under the optimal extraction conditions, the developed method exhibited excellent linearity over the concentration range of 0.01-5.0 µg/L, low limits of detection ranging from 3.0 to 5.1 ng/L, relative standard deviations less than 4.1%, and enrichment factors between 182 and 204 for PCBs. Finally, the effectiveness of the developed method was successfully demonstrated through residue determination of PCBs in water samples.

A green liquid phase microextraction using phthalic acid as switchable hydrophilicity solvent for the HPLC determination of sildenafil (Viagra®) in human urine

Herein, a green liquid phase microextraction protocol using phthalic acid as switchable hydrophilicity solvent (SHS) is reported for the quantification of sildenafil in authentic human urine. The analyte was extracted onto phthalic acid solid particles which were produced through acidification of the sample. Its solidification was accomplished at ambient conditions without sample cooling. The determination of the sildenafil was carried out using high performance liquid chromatography-ultraviolet detection (HPLC-UV). The microextraction parameters that affect the extraction efficiency of the drug (i.e. SHS type and its concentration, acid type and concentration, extraction time, filter type) have been studied. The optimized analytical protocol involved the mixing of 300 μL of phthalate solution (0.75 M) with 600 μL of sample, followed by the addition of 50 μL of concentrated H3PO4. The produced solid was collected using membrane syringe filter (0.45 μm) and was finally dissolved in 500 μL of CH3OH. Method validation data showed determination coefficient ≥ 0.99 for the linear range of 50 – 2000 ng/mL. The limit of detection (LOD) and the lower limit of quantitation (LLOQ) were 30 and 100 ng/mL, respectively. The accuracy (expressed as % recovery) of the method ranged between 88.0 – 108.9 % while the precision (expressed as % RSD) was less than 17.8 % in all cases. The robustness of the microextraction procedure and the instrumental method were investigated using Plackett-Burman experimental designs. The applicability of the method was demonstrated by analyzing both spiked and authentic human urine samples after oral administration of drug-containing pharmaceutical formulation. The developed protocol offers cost-efficiency, handling simplicity, and high throughput. Its green character was evaluated using Green Analytical Procedure Index and Blue Applicability Grade Index.

Synthesis and Properties of Hydrophilic and Hydrophobic Deep Eutectic Solvents via Heating-Stirring and Ultrasound.

Deep eutectic solvents (DESs) have emerged as a greener alternative to other more polluting traditional solvents and have attracted a lot of interest in the last two decades. The DESs are less toxic dissolvents and have a lower environmental footprint. This paper presents an alternative synthesis method to the classical heating-stirring method. The ultrasound method is one of the most promising synthesis methods for DESs in terms of yield and energy efficiency. Therefore, the ultrasound synthesis method was studied to obtain hydrophobic (Aliquat 336:L-Menthol (3:7); Lidocaine:Decanoic acid (1:2)) and hydrophilic DESs based on choline chloride, urea, ethylene glycol and oxalic acid. The physical characterization of DESs via comparison of Fourier transform infrared (FTIR) spectra showed no difference between the DESs obtained by heating-stirring and ultrasound synthesis methods. The study and comparison of all the prepared DESs were carried out via nuclear magnetic resonance spectroscopy (NMR). The density and viscosity properties of DESs were evaluated. The density values were similar for both synthesis methods. However, differences in viscosity values were detected due to the presence of some water in hygroscopic DESs.

Enhancing Liquid-Crystalline Order and Fluidity of a Hydrophobic Host with Trace Hydrophilic Solvent

Enhancing Liquid-Crystalline Order and Fluidity of a Hydrophobic Host with Trace Hydrophilic Solvent

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.

Amine Switchable Hydrophilic Solvent Vortex-Assisted Homogeneous Liquid-Liquid Microextraction and GC-MS for the Enrichment and Determination of 2, 6-DIPA Additive in Biodegradable Film.

2, 6-diisopropylaniline (2, 6-DIPA) is a crucial non-intentionally organic additive that allows the assessment of the production processes, formulation qualities, and performance variations in biodegradable mulching film. Moreover, its release into the environment may have certain effects on human health. Hence, this study developed simultaneous heating hydrolysis-extraction and amine switchable hydrophilic solvent vortex-assisted homogeneous liquid-liquid microextraction for the gas chromatography-mass spectrometry analysis of the 2, 6-DIPA additive and its corresponding isocyanates in poly(butylene adipate-co-terephthalate) (PBAT) biodegradable agricultural mulching films. The heating hydrolysis-extraction conditions and factors influencing the efficiency of homogeneous liquid-liquid microextraction, such as the type and volume of amine, homogeneous-phase and phase separation transition pH, and extraction time were investigated and optimized. The optimum heating hydrolysis-extraction conditions were found to be a H2SO4 concentration of 2.5 M, heating temperature of 87.8 °C, and hydrolysis-extraction time of 3.0 h. As a switchable hydrophilic solvent, dipropylamine does not require a dispersant. Vortex assistance is helpful to speed up the extraction. Under the optimum experimental conditions, this method exhibits a better linearity (0.0144~7.200 μg mL-1 with R = 0.9986), low limit of detection and quantification (0.0033 μg g-1 and 0.0103 μg g-1), high extraction recovery (92.5~105.4%), desirable intra- and inter-day precision (relative standard deviation less than 4.1% and 4.7%), and high enrichment factor (90.9). Finally, this method was successfully applied to detect the content of the additive 2, 6-DIPA in PBAT biodegradable agricultural mulching films, thus facilitating production process monitoring or safety assessments.