Extraction techniques with deep eutectic solvents

Extraction of carotenoids from tomato pomace using deep eutectic solvents composed of short and medium-chain fatty acids and menthol

Tomatoes are rich in carotenoids, which remain in significant quantities in tomato pomace and can be sustainably extracted. This study aimed to develop a method for extracting carotenoids from tomato pomace using deep eutectic solvents composed of menthol and fatty acids (butyric, hexanoic, caprylic, lauric, and palmitic), as an alternative to toxic and polluting organic solvents. Preliminary screening identified the most effective deep eutectic solvent, while design of experiment and a kinetic study optimized the extraction process. Under optimal conditions, the DES extracted approximately 300 μg/g of carotenoids on a dry weight basis. HPLC analysis of the extract quantified 24 μg/g ± 5 of β-carotene and 52 μg/g ± 2 of lycopene. The menthol-butyric acid DES outperformed conventional organic solvents, emphasizing its sustainability and efficiency.

The Physicochemical Properties and Plausible Implication of Deep Eutectic Solvents in Analytical Techniques

Volatile organic solvents and fluoride-containing ionic liquids (ILs) have few drawbacks like toxicity, non-biodegradability, and environmental issues. Even though ILs are considered as new safest solvent for their lower volatility. They pose toxicity and sustainability concerns. Deep eutectic solvents (DESs) have garnered significant attention as substitutes for these solvents, addressing their drawbacks and aligning with specific principles of green chemistry, such as reduced toxicity, biodegradability, and the use of renewable resources. This review thoroughly explains the emergence and inception of DESs through their development. It deals with the physicochemical properties like density, polarity, and viscosity. The factors dealing with variation in density and viscosity of DES have been discussed. The preparation and operation of DESs, encompassing their various variants such as hydrophobic and hydrophilic types are examined to provide a comprehensive grasp of their chemical properties. Beyond basic characteristics, the article delves into a few specific DES applications to demonstrate their flexibility. DESs show promising multifarious utility, ranging from acting as extractant to critical roles in sorbent-based extractions, solvent-based extractions, and their role in various analytical techniques. The article covers the opportunities and difficulties associated with DESs, offering a prospective viewpoint on future advancements and difficulties. The review outlines different facets of DES research, emphasizing the level of knowledge at the moment and their potential influence in the emerging subject of DESs.

Enhancing the Mechanical Properties of Electrospun Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) Fiber Mats Using Deep Eutectic Solvents

In this study, the use of deep eutectic solvents (DESs) was considered for the first time to improve the mechanical properties of electrospun poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) fiber mats. For this, different DES formulations, namely, Choline Chloride (ChCl):Urea:Water, ChCl:Glycerol (Gly), and Gly:Sodium Citrate (NaCitrate), were selected and evaluated at a concentration of 10 wt %, and their efficacy enhancing mechanical properties was compared against traditional plasticizing additives glycerol and acetyl tributyl citrate (ATBC). The impact of these formulations on PHBV fiber mats was evaluated in terms of thermal, crystallinity, and mechanical properties, both as obtained and after aging. All samples produced macroscopically consistent, self-supporting, and handleable nonwoven material sheets. The DES-containing PHBV showed a thinner, bead-free surface morphology but a rugose surface morphology. DSC results indicated that glycerol, ATBC, and Gly:NaCitrate (DES) exhibited the highest reduction in melting temperatures, with a notable 5.6 °C decrease for the mat containing Gly:NaCitrate. Interestingly, electrospun PHBV fibers containing DES revealed a larger quantity of β-form planar zigzag chain conformations, so-called β-form crystals. Tensile test results revealed that depending on the additive formulation, the mechanical performance of the samples was fundamentally different from each other. Among DESs, PHBV fiber mats with ChCl-based DES were excessively brittle. Surprisingly and interestingly, PHBV fiber mats containing Gly:NaCitrate exhibited an unreported significant increase in all mechanical properties, including modulus, elongation at break, and toughness. Overall, this study highlights the potential of DESs as unique additives to tailor the mechanical properties of electrospun PHBV materials.

Optimization of Deep Eutectic Solvent-Based Ultrasound-Assisted Extraction of Bioactive Compounds from Maca Leaves Using the Taguchi Method

This study was conducted to identify the optimal conditions and evaluate the feasibility of deep eutectic solvent (DES)-based ultrasound-assisted extraction (UAE) for utilizing maca (Lepidium meyenii) leaves, an agricultural by-product, as functional materials. The extraction parameters influencing the recovery of saponins and polyphenols, which are major bioactive compounds, were analyzed using the Taguchi method. Results: Signal-to-noise ratios and analysis of variance indicated that the liquid-solid ratio was the most critical factor for optimizing the extraction process. The optimal extraction conditions were determined to be a liquid-solid ratio of 40 mL/g, a water content in DES of 30%, an extraction time of 30 min, and an ultrasonic power of 300 W in the DES system consisting of choline chloride and glycerin in the molar ratio of 1:2. Maca leaf extract obtained under optimized DES-based UAE conditions exhibited higher bioactive compounds content and antioxidant activity compared with that obtained by hot water extraction. Therefore, the DES-based UAE method is a promising, eco-friendly alternative for extracting bioactive compounds from maca leaves.

A novel DES-enhanced sodium alginate-based conductive organohydrogel fiber for high-performance wearable sensors

Conductive organohydrogel fibers based on sodium alginate (SA) exhibit remarkable flexibility and electrical conductivity, making them ideal candidates for conformal skin adhesion and real-time monitoring of human activity signals. However, traditional conductive hydrogels often suffer from issues such as uneven distribution of conductive fillers, and achieving the integration of high mechanical strength, stretchability, and transparency using environmentally friendly methods remains a significant challenge. In this study, a novel and sustainable strategy was developed to fabricate dual-network organohydrogel fibers using sodium alginate as the primary material. By incorporating a deep eutectic solvent (DES) composed of choline chloride and glycerol into the SA matrix through wet spinning, the mechanical properties of the hydrogel were significantly enhanced, achieving an elongation at break of 817 % and a tensile strength of 5.12 MPa. The resulting fibers exhibit stable electrical conductivity and outstanding performance as wearable sensors, enabling accurate and reliable real-time monitoring of diverse human activities. This innovative approach highlights the potential of SA-based conductive hydrogels for multifunctional sensing applications. By addressing the limitations of traditional hydrogels and leveraging the biocompatibility and scalability of SA, this method opens new avenues for advanced wearable electronics and biomedical devices that are sustainable, durable, and versatile.

Application of deep eutectic solvents for the simultaneous determination of organophosphorus and pyrethroid pesticides in aqueous matrices and the assessment of its level of whiteness

This work presents as a novelty the development of a method for the simultaneous determination of organophosphorus and pyrethroid pesticides in aqueous samples using only deep eutectic solvents (DES) followed by a gas chromatography-mass spectrometry analysis. Combining 4 hydrogen bond acceptors and 6 hydrogen bond donors, 17 DES were prepared. Menthol:thymol in a 1:1 molar ratio presented the best extraction performance and was, therefore, characterized by Fourier transform infrared spectroscopy (FTIR), hydrogen-nuclear magnetic resonance (1H NMR) and nuclear Overhauser effect spectroscopy (NOESY-NMR), comparing the spectra from the pure components and from the DES. In the FTIR analysis, the main shifts occurred in the CO bonds. The NMR analyses allowed a better understanding of the interactions occurring during solvent formation, which were attributed to the interaction between the hydroxyls from menthol and thymol. Vortex-assisted dispersive liquid-liquid microextraction (DLLME) required no dispersing solvents. The main variables affecting the extraction were optimized using full factorial design, including a triplicate center point. For a fixed 10-mL sample volume, the optimum ranges obtained were: 3.0 ± 0.60 g of NaCl, pH in the range from 5 to 9, a vortex stirring time of 4 ± 2 min and 150 μL of a DES composed of menthol and thymol in a 1:1 molar ratio. Satisfactory figures of merit were then obtained: coefficients of determination greater than 0.99, linear working ranges from 1 μg/L to 400 μg/L, limit of detections of 0.3 μg/L, an inter-day precision from 1.33 % to 9.86 % (n = 12), and an intra-day precision from 4.65 % to 15.52 % (n = 4). The application was carried out in six different aqueous matrices, with methyl parathion being detected in a lake sample. An excellent mean recovery of 98.0 % was obtained for the three levels evaluated and all analytes. The comparison with other methods was based on the principles of White Analytical Chemistry using Algorithm 12, by which the method proposed in this work showed a higher level of whiteness compared to the others.

Evaluation of the Inhibition Performance of a Hybrid Depth Eutectic Solvent Used as an Inhibitor for Water-Based Drilling Fluids and Its Mechanistic Analysis

Drilling instability in oil and gas drilling has long challenged drilling safety and economics. Conventional oil-based drilling fluids offer high-temperature resistance and good inhibition. However, oil-based drilling fluids have significant problems in terms of environmental impact, cost, and waste fluid disposal. This has led to the widespread use of water-based drilling fluids. This study aims to investigate the synthesis of a new water-based drilling fluid inhibitor, a hybrid low eutectic solvent ChCl-Gly-Urea (CGU-DES), and its performance evaluation. While conventional eutectic solvents (DES) usually consist of a single type of hydrogen bond acceptor (HBA) and hydrogen bond donor (HBD), CGU-DES extends its performance characteristics by introducing a combination of one HBA and two HBDs. The study confirmed the successful synthesis of CGU-DES using FT-IR spectroscopy. The following advantages of CGU-DES over CU-DES and CU-DES consisting of a single type of HBA and HBD were verified. Below 175 °C, the temperature resistance of CGU-DES is better, and the mass loss rate is less than 5%. The first and second rolling recoveries of CGU-DES aqueous solution with low concentration (<0.5 wt %) were greater than 95% and 85%, respectively, higher than the rolling recoveries of CG-DES and CU-DES.CGU-DES has a good ability to reduce water activity. When the dosage is 10%, the activity of DES aqueous solution is less than 0.950, and the efficiency of reducing water activity is nearly twice that of CG-DES and CU-DES. CGU-DES is compatible with sodium slurry and drilling fluids with polymer-sulfonated materials because it has little influence on rheology and fluid loss. At 180 °C, 0.7% CGU-DES was added to the polysulfonate drilling fluid system, and the fluid loss reduction rate reached 30.59%. Experiments show that CGU-DES can inhibit the hydration and dispersion of shale by inserting into the crystal spacing of montmorillonite , adsorbing onto the surface, reducing the surface tension of drilling fluid, reducing the contact angle between drilling fluid and shale, and reducing the water activity of drilling fluid. In summary, CGU-DES, a new type of green solvent, has potential application prospects in water-based drilling fluids and provides new technical support for solving the borehole instability problem during drilling.

Green extraction and IC analysis of trace impurities in TATB through deep eutectic solvents

1,3,5-trinamino-2,4,6-trinitrobenzene (TATB) as an important insensitive high explosive has excellent safety performance due to strong hydrogen bonds. Ionic impurities including sulfate ions (SO42-), nitrate ions (NO3-) and chloride ions (Cl-) formed during the preparation of TATB have negative effects on TATB-based explosives. However, strong hydrogen bonds result in extremely low solubility of TATB in traditional solvents, which poses a huge obstacle to extract and detect the impurities in TATB for quality control. In this study, a green extraction method based deep eutectic solvent (CS-1) was firstly developed for the extraction of trace impurities in TATB. After the dissolution of TATB in CS-1 solvent, water (H2O) was used as a green hydrogen bond donor to differentiate the solubility between TATB and its ionic impurities. Through the above strategy, TATB was efficiently removed and the impurities were selectively extracted in CS-1 solvent. Meanwhile, Ca(OH)2 as a precipitant was investigated to eliminate the background interference of F- ions in CS-1 solvent through forming the precipitate of CaF2. Further, the extraction of deep eutectic solvent was combined with ion chromatography (IC) to develop an analytical method for trace impurities. This method displays excellent separation, high sensitivity and good repeatability toward four ionic impurities (Cl-, NO2-, NO3- and SO42-). Compared to traditional methods (DMSO method and oxygen flask combustion method) with low extraction ability, indirect detection and dangerous pretreatment, this method provides direct, convenient and accurate detection of anionic impurities in TATB, and displays better application for quality control of TATB.

Optimized extraction of Spirulina platensis phenolics using natural deep eutectic solvents for cosmetics

This study presents a highly environmentally friendly system using natural deep eutectic solvent (NADES) as an organic solvent substitute to obtain high-quality microalgae extract, which is a potential new source of moisturizing cosmetic materials. Blue-green algae Spirulina platensis was selected as the alg metabolite source. Choline chloride and glycerol were used as the ingredients of the NADES owing to they are commonly used in cosmetic products for skin moisturizing and/or healing. The extraction of bioactives from Spirulina platensis was optimized based on the multi-response optimizition of Response Surface method (RSM). 3-factor and 3-level Box-Behnken design was implemented for the design matrix with 17 experimental runs. The best conditions were attained by almost 21% (v/v) water addition into the best NADES (choline chloride/glycerol, ½ molar ratio) for 30 sec of extraction time under almost 7500 rpm mixing speed. The given conditions provided the highest yields of total phenolic content (10.517 mg-GAE/g-DM), antioxidant activity (1.796 mg-TEAC/g-DM) and 1,2,3,4-butanetetrol (70.174%), which were approved with satisfactory validation findings (the error < 2%). The application of the produced products gave promising findings for the valorization of the NADES-based alg metabolites as potential natural additives used directly in cosmetic formulations.

Cocktail enzyme-assisted natural deep eutectic solvent for enhanced extraction of capsaicin from chili peppers: Mechanism exploration based on multi-experiments and molecular dynamic simulation

The cocktail enzyme-assisted natural deep eutectic solvent (CE-NADES) has been tailored for the efficient extraction of capsaicin, the characteristic bioactive compound of chili peppers (CPs), in this study. The extraction procedures were optimized as choline chloride:1,4-butanediol (molar ratio 1:3), extraction temperature 38 °C, liquid-solid ratio 27.5 mL/g, water content 17.8 % (v/v) and extraction time 28 min, which yield was 9.91 ± 0.13 mg/g. Moreover, CE pretreatment, by destroying plant structures, accelerated the release of capsaicin and consequently reduced the maximum decomposition temperature of CP residues to 260.5 °C after extraction. Meanwhile, more hydrogen bonds (134.72 at lifetime 3.98 ps) formed between capsaicin and NADES to facilitate the mass transfer. Larger solvent accessible surface area (210.09 nm2) and lower average interaction energy (-455.12 kJ/mol) enhanced the stability and solubility of capsaicin. Overall, CE-NADES could serve as an industrialized and green alternative method for the efficient extraction of capsaicin.

Highly efficient esterification of waxy maize starch in choline chloride/acetic acid acidic deep eutectic solvent system

In this study, to address the issue of solvent selection in the chemical modification of starch, a method was developed for the efficient esterification of waxy maize starch (WMS) using an acidic deep eutectic solvent composed of choline chloride and acetic acid (CCHAc-ADES). The impact of different mass fractions of CCHAc-ADES on the degree of substitution and reaction efficiency of lauric acid starch esters was explored. It was found that under the conditions of 70 wt% CCHAc-ADES, starch esters with the highest degree of substitution of 0.161 were successfully prepared, achieving an esterification efficiency of 79.63 %. 13C and 1H nuclear magnetic resonance spectroscopy, X-ray diffraction and gel permeation chromatography revealed that CCHAc-ADES acted within the surface voids of WMS particles without seriously damaging the WMS structure, making it a favorable solvent for chemical modification of WMS. By monitoring changes in the morphology, relative crystallinity, particle size, and hydrophobicity of esterified WMS in CCHAc-ADES, the formation mechanism of lauric acid starch esters was inferred, primarily related to the competitive hydrogen bonding of CCHAc-ADES with WMS. The method proposed in this study allows for the preparation of long-chain fatty acid starch esters without the use of any additional chemicals or enzymes, offering significant guidance for the application of deep eutectic solvents in green synthesis.

Extraction mechanism and bio-activities of capsaicinoids from lantern peppers placenta using deep eutectic solvents

This study proposed ultrasound-assisted deep eutectic solvent (DES) for the extraction of capsaicinoids (CAP) from the placenta of lantern peppers. The DES of choline chloride-citric acid (ChCl-CA), with the highest CAP yield (8.25 mg/g) was screened. 1H nuclear magnetic resonance and Fourier transform infrared spectroscopy showed that the ChCl-CA formed hydrogen bonds through -COOH of CA and N+Cl- of ChCl. Furthermore, the CAP preferred the diffusion of ChCl during the extraction of CAP, which indicated that ChCl played a better solvent role in the DES via molecular dynamics. High-performance liquid chromatography results showed capsaicin (65.02 %) as the major compound in the extracts. Notably, DES-extracted CAP had excellent antioxidant activity and provided enhanced inhibition of Escherichia coli and Staphylococcus aureus. Thus, this study will provide a reference for the future use of DES in the extraction of other alkaloids, either in the laboratory or the industry.

Trends in pretreatment and determination methods for furfurals in foods: Update since 2017

BACKGROUND

Furfurals, key derivatives of Maillard reactions commonly found in everyday foods, have been identified as having significant toxic effects on human health. Excessive intake of furfurals can lead symptoms such as weight loss, poor nutrient metabolism which followed by disease occurrence. The severe carcinogenicity, mutagenicity and genotoxicity of furfurals were well recognized recently. In response, international organizations have established strict limits on the allowable levels of furfurals in food products. Therefore, it is of paramount importance to implement control which mediated by modern pretreatment and analytical techniques, towards the daily accessibility of furfurals.

SCOPE AND APPROACH

This review seeks to present a comprehensive overview of recent advancements in the pretreatment and analytical techniques for furfurals in food from 2017 to 2023. Various pretreatment methods, such as liquid phase microextraction, solid phase extraction, solid phase microextraction, and QuEChERS, as well as analytical technologies like liquid chromatography-based methods and gas chromatography-based methods, are thoroughly discussed in terms of their mechanisms, benefits, and limitations.

KEY FINDINGS AND CONCLUSIONS

Currently, various pretreatment and analytical techniques with advantages and limitations had been proposed. The development of novel materials does facilitate the optimization and application of microextraction based pretreatment platforms which share with enhanced extraction efficiency. In addition, the development of novel targeting/sensing materials along with the utilization of high-resolution mass spectrometry could promote the determination sensitivity. In future, development of novel absorbents which mediates more desirable pretreatment methods, and automated and miniaturized on-site analytical instruments for furfurals determination still deserve indepth invesigation.

Green extraction using natural deep eutectic solvents for determination of As, Cd, and Pb in plant and food matrices by ICP-MS

In this study, extraction methods using natural deep eutectic solvents (NADES) were proposed for the determination of arsenic (As), cadmium (Cd), and lead (Pb) in plant and food matrices. NADES are green and sustainable solvents with advantageous chemical properties for such applications. The NADES were prepared with different components, characterized, and applied in ultrasound-assisted extraction (UAE) and microwave-assisted extraction (MAE) methods. Experimental variables including temperature, extraction time, and sample-solvent ratio, were investigated using experimental designs to establish the optimal extraction conditions before analysis by ICP-MS. For the MAE method, the optimal conditions were extraction temperature of 100 °C, extraction time of 40 min, and SSR of 40:1 m v-1, resulting in recoveries of up to 84 %. For the UAE method, the optimal conditions were 40 °C, 40 min, and sample-solvent ratio (SSR) of 30:1 m v-1, with recoveries ranging from 96 % to 109 %, all with relative standard deviations less than 11 %. The proposed methods provided low detection limits (mg kg-1), with values of <0.0160 for As, <0.0030 for Cd, and < 0.0090 for Pb for UAE and MAE. The methods were considered green, achieving scores of 0.54 (MAE) and 0.45 (UAE) on the analytical greenness metric for sample preparation. The use of NADES as efficient extractants, combined with multivariate optimization, resulted in optimal experimental conditions, good analytical performance, and enhanced sustainability. The proposed method is a promising approach for applications in food safety and public health studies.

Selective microextraction of erythrosine (E127) in foodstuffs using a new generation high-density type-V deep eutectic solvent

A novel and selective (deep eutectic solvent) DES-based microextraction method was established for the first time, utilizing a synthesized new generation High-Density Type-V DES for monitoring the dye Erythrosine (E127) in various foodstuffs and drugs. Type-V DES was created from acetophenone and diphenylamine at 3:1 M ratio. The pH, DES amount, and vortex time were optimized using Box-Behnken Design (BBD) of Response Surface Methodology (RSM). The quadratic microextraction model with R2 = 0.9982 was obtained. The limit of detection, preconcentration factor and linear dynamic range were determined to be 12 μg/L, 50 and 41-4000 μg/L, respectively. Effects of matrix components were examined. The developed High-Density Type-V Deep Eutectic Solvent Microextraction (HD-V-DES-ME) method was applied to foodstuffs and drugs to monitor their E127 contents and subsequently validated by applying spiked tests to real samples, with recoveries ranging between 94 and 101 %. The indexes of environmental friendliness and practicality for the method were evaluated using the Analytical GREEnness metric approach tool (AGREE) and the Blue Applicability Grade Index tool (BAGI), respectively.

Electron beam irradiation coupled ultrasound-assisted natural deep eutectic solvents extraction: A green and efficient extraction strategy for proanthocyanidin from walnut green husk

Proanthocyanidin (PAC) is recognized as a potent natural antioxidant that prevents various diseases. As societal awareness increases, eco-friendly and efficient natural product extraction technologies are gaining more attention. In this study, an electron beam irradiation (EBI) coupled with ultrasound-assisted natural deep eutectic solvents (NADES) extraction method was developed to enable the green and highly efficient extraction of PAC from walnut green husk (WGH). NADES, prepared with choline chloride and ethylene glycol, demonstrated excellent extraction capacity and storage stability for PAC. Molecular dynamics simulations elucidated the high compatibility between NADES and PAC, attributed mainly to a higher SASA value (207.85 nm2), a greater number of hydrogen bonds (330.99), an extended hydrogen bonding lifetime (4.54 ps), and lower inter-molecular interaction energy. Based on these findings, the optimal conditions (13 kGy EBI, 42 mL/g liquid-solid ratio, 38 °C extraction temperature, 70 min extraction time) resulted in a maximum PAC extraction yield of 56.34 mg/g. Notably, this yield was 32.93 % higher than that observed in samples not treated with EBI and ultrasound-assisted extraction (UAE). Analysis of tissue morphology, extract functional groups and thermal behavior suggested a possible mechanism for the synergistically enhanced PAC extraction by the EBI-NADES-UAE method. Additionally, the PAC extracted using the NADES by the EBI coupled with ultrasound-assisted method exhibited outstanding antioxidant activity (comparable to Vc), digestive enzyme inhibition (IC50: 17-0.61 mg/mL), and anti-glycation capacity (IC50: 86.49 μg/mL). Overall, this work provided a green and efficient strategy for PAC extraction from WGH, elucidated the extraction mechanism and bioactivities, and offered valuable insights for potential industrial applications.

Optimization of Eco-Friendly Extraction of Bioactive Compounds from Mentha spicata L. Using Ultrasound-Assisted Extraction Combined with Choline Chloride-Based Deep Eutectic Solvents

Three choline chloride (ChCl)-based deep eutectic solvents (DESs) as a new type of green solvents were used for the ultrasound-assisted extraction (UAE) of bioactive compounds from Mentha spicata L. DES containing ChCl and malonic acid (MalA) was selected as the most promising, providing a more effective extraction of antioxidants from spearmint. Response surface methodology (RSM) and a Box-Behnken design (BBD) with three variables, ChCl:MalA molar ratio, water content (WC) in DES, and extraction time (t), were implemented for optimizing the extraction conditions. The optimal conditions were calculated to maximize the antioxidant capacity (AC) determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and cupric reducing antioxidant capacity (CUPRAC) assays, total phenolic acids (TPAc), total flavonoid aglycones (TFAgly), and total flavonoid glycosides (TFGly). The phenolic profiles in the obtained extracts were analyzed using ultra-performance liquid chromatography (UPLC), revealing that rosmarinic acid, ellagic acid, rutin, kaempferol, and kaempferol-3-O-rutinoside were predominant in the DES extracts.

Green extraction of prostaglandin analogs in cosmetics using deep eutectic solvents and detection via LC-MS/MS

Prostaglandin analogs (bimatoprost, travoprost, tafluprost, etc.) have similar effects to prostaglandins and are effective drugs for treating glaucoma. These compounds exhibit abnormal reactions such as causing eyelash growth, with several cases being reported of people purchasing them to increase eyelash growth; however, some cases have reported side effects such as pigmentation and dry eyes. In the Republic of Korea, cosmetics are not medicines for treating diseases; therefore, cosmetics cannot contain drugs or have labels that could mislead people. However, there are cases in which products claim to elongate and enrich eyelashes. Concerns about the abnormal reactions of these products are constantly growing, and the absence of analytical methods for illicit compounds (prostaglandins and their analogs) in cosmetics (eyelash growth serums) renders monitoring challenging. Accordingly, in this study, we sought to develop an LC-MS/MS method for facile and fast analysis of compounds illegally mixed into eyelash growth serums. Green analytical chemistry has recently emerged because of environmental concerns. In line with this trend, we developed an optimal method by comparing the methods mainly used in cosmetic pretreatment (solvent extraction, QuEChERS, and solid phase extraction) with a method using deep eutectic solvents (DESs), which is an eco-friendly solvent. As a result of validation according to the International Conference on Harmonization guidelines, the limit of detection was 0.20-9.34 ng/mL, and the limit of quantification was 0.60-28.31 ng/mL. Recovery, linearity, precision, and accuracy were within acceptable ranges. Additionally, using the Analytical GREEnness calculator and complex green analytical procedure index tools, we confirmed that the method using the DES was greener than the other methods. In this study, we developed an analytical method for illicit compounds contained in eyelash growth serums, offering an eco-friendly approach for the prevention of the distribution of illegal cosmetics.

Fast Dissolution of Chitin in Amino Acids Based Deep Eutectic Solvents Under the Assistance of Microwave

Due to the abundant hydrogen bond networks, high crystallinity, and high molecular weight of chitin, it is difficult to dissolve chitin in most solvents. Meanwhile, most of the existing solvent systems have the disadvantages of high toxicity, low solubility, and high cost. Therefore, the efficient and rapid dissolution of chitin using green solvents is urgently needed. In this work, ternary DES with amino acids, urea, and 1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU) is prepared at first. Then chitin can be dissolved fastly with the assistance of a microwave. Compared with the conventional heating process (110 °C, 6-8 h), the microwave process can be shortened to only 3-10 min. The successful dissolution of chitin is verified by means of fourier transform infrared spectrometer (FT-IR), X-ray diffraction (XRD), rheology studies, and optical light microscope, and the dissolution mechanism contributed to the synergistic destroying of the hydrogen bond networks of chitin by amino acids and DBU. The DES solvent can be well recovered with the remaining of its dissolving ability to chitin.

Marine cosmetics and the blue bioeconomy: From sourcing to success stories

As the global population continues to grow, so does the demand for longer, healthier lives and environmentally responsible choices. Consumers are increasingly drawn to naturally sourced products with proven health and wellbeing benefits. The marine environment presents a promising yet underexplored resource for the cosmetics industry, offering bioactive compounds with the potential for safe and biocompatible ingredients. This manuscript provides a comprehensive overview of the potential of marine organisms for cosmetics production, highlighting marine-derived compounds and their applications in skin/hair/oral-care products, cosmeceuticals and more. It also lays down critical safety considerations and addresses the methodologies for sourcing marine compounds, including harvesting, the biorefinery concept, use of systems biology for enhanced product development, and the relevant regulatory landscape. The review is enriched by three case studies: design of macroalgal skincare products in Iceland, establishment of a microalgal cosmetics spin-off in Italy, and the utilization of marine proteins for cosmeceutical applications.

The perfect match between macroalgae and eutectic solvents as a sustainable gateway to ready-to-use extracts towards a (blue + green) economy ─ A perspective review

The article discusses how aligning with the Sustainable Development Goals (SDGs) can foster a sustainable economy, mainly through the (green + blue) economy, which involves valorizing macroalgae to produce ready-to-use extracts. It focuses on the potential of eutectic solvents (commonly known as deep eutectic solvents - DES) as promising candidates for this purpose. Traditional methods for extracting bioactive compounds from macroalgae, which rely on organic solvents and aqueous buffers, often involve harsh conditions and extensive processing. These factors can lead to reduced extract quality and/or low yields. In contrast, if properly designed, DES presents a green and sustainable alternative. They offer advantages such as low volatility, adjustable polarity, and negligible toxicity, making them a more environmentally friendly and efficient option for extraction processes. They can be customized to enhance both biological and technological properties, resulting in extracts with unique characteristics such as increased antioxidant activity, antiproliferative and anti-inflammatory effects, as well as improving the viscoelasticity of polysaccharides (fucoidans, alginates, and κ-carrageenan) from macroalgae. In this sense, the tunable nature of DES enables the optimization of extraction conditions to maximize yield, purity, and bioactivity, making it a smart alternative for producing bio-based products. Despite limited literature on DES for this purpose, the article highlights their potential and outlines the main advantages and challenges needed for macroalgae valorization.

Assessing Melting and Solid-Solid Transition Properties of Choline Chloride via Molecular Dynamics Simulations

Choline chloride (ChCl) is used extensively as a hydrogen bond donor in deep eutectic solvents (DESs). However, determining its melting properties experimentally is challenging due to decomposition upon melting, leading to widely varying literature values. Accurate melting properties are crucial for understanding the solid-liquid phase behavior of ChCl-containing DESs. Here, we employ molecular dynamics simulations to compute the phase transitions of ChCl, testing a variety of atomistic force fields. We find that the results are sensitive to the choice of force field, but a melting temperature of 627 K and a melting enthalpy of 7.8 kJ/mol seem most reasonable, in good agreement with some literature values. We suggest these as the likely melting properties of ChCl, though the results are tentative due to limited experimental data for the liquid ChCl phase.

Deep eutectic supramolecular polymers based HPLC stationary phase: Green synthesis strategy and promising application prospects

BACKGROUND

Deep eutectic solvents (DESs) have been widely and significantly applied in various fields due to their outstanding features such as low cost, easy preparation and good biodegradability. As novel derivatives of DESs, deep eutectic supramolecular polymers (DESPs) combine the macroscopic state of DESs with the covalent interactions of supramolecular polymers, which also possess the properties of DESs as multifunctional materials. Therefore, DESPs are believed to be promising candidates for separation science. However, there are no studies on the application of DESPs as stationary phases for HPLC analysis.

RESULTS

In this work, a novel DESP based HPLC stationary phase (Poly(DES)@SiO2) was developed for the first time through a green synthesis method by using DES as the polymerization monomer as well as the reaction medium. The results manifest that this novel Poly(DES)@SiO2 column can well interact with analytes through various mechanisms, and realize selective separation of a wide range of structurally similar hydrophilic/hydrophobic substances. More importantly, the separation of hydrophobic analytes on the Poly(DES)@SiO2 column is less time-consuming with fewer organic eluent, although the column efficiency is slightly lower than that of commercial C18 column. Furthermore, the Poly(DES)@SiO2 column exhibits excellent mechanical stability and satisfactory separation repeatability for steroid hormones. Therefore, a reliable method was established for detecting steroid hormones in actual samples with the recoveries ranging from 94.56 % to 103.84 %, which can meet the detection needs of commonly seen steroid hormones in food and the environment.

SIGNIFICANCE

In summary, this work provides some valuable theoretical references for the synthesis of new DESP based stationary phases through a green and facile strategy, and meanwhile, verifies the feasibility of DESP for effective HPLC separations. In addition, the promising application prospect of DESP based stationary phases in the analysis of complex samples has also been demonstrated, expanding the potential application of DES in separation science.

Antimicrobial Effectiveness of Ribes nigrum L. Leaf Extracts Prepared in Natural Deep Eutectic Solvents (NaDESs)

BACKGROUND

Blackcurrant (Ribes nigrum L.) leaves are valuable sources of bioactive compounds, including phenolic acids, flavonoids, and tannins, which contribute to their potent antioxidant, anti-inflammatory, and antimicrobial properties.

OBJECTIVES

The overall aim of this study was to investigate the antimicrobial potential of extracts rich in bioactive compounds from blackcurrant leaves prepared in natural deep eutectic solvents (NaDESs). The objectives included the optimization of polyphenols extraction in NaDESs, characterization of the phytochemical composition by liquid chromatography-mass spectrometry (LC-MS), explanation of the chemical interactions between solvent systems and the main bioactive compound (chlorogenic acid) by molecular dynamics simulations, and evaluation of biological efficacy through antimicrobial tests.

METHODS

Two hydrogen-bond acceptors (HBAs) and three hydrogen-bond donors (HBDs) were tested. The experimental design included variables such as the HBA:HBD molar ratio, water percentage, extraction time, and extraction techniques used, specifically ultrasound-assisted extraction (UAE) and ultra-turrax extraction (UTE). The evaluated responses included the total polyphenol content, total flavonoid content, and total antioxidant activity. Antimicrobial assays were performed on four Gram-positive and three Gram-negative bacterial species, as well as one fungus, Candida albicans.

RESULTS

The extracts obtained by UAE showed higher concentrations of polyphenols and increased antioxidant potential. LC-MS analysis revealed the predominant presence of chlorogenic acid. The extracts showed significant activities against Gram-positive bacteria and Candida albicans.

CONCLUSIONS

This study highlights the antioxidant and antimicrobial potentials of blackcurrant leaves extracts prepared in NaDESs, confirming that this type of solvent enhances polyphenols extraction and offers perspectives for new therapeutic formulations.

Utilization of Cobalt and its Oxide/Hydroxide Mediated by Ionic Liquids/Deep Eutectic Solvents as Catalysts in Water Splitting

With the ever-growing global demand for sustainable energy solutions, hydrogen has garnered significant attention as a clean, efficient, and renewable energy source. In the field of hydrogen production, catalyst research stands out as one of the foremost areas of focus. In recent years, the preparation of electrocatalysts using ionic liquids (ILs) and deep eutectic solvents (DESs) has attracted widespread attention. ILs and DESs possess unique physicochemical properties and are recognized as green media as well as functional materials. Cobalt-based catalysts have proven to be efficient electrocatalysts for water splitting. Incorporating ILs or DESs into the preparation of cobalt-based catalysts offers a remarkable advantage by allowing precise control over their structural design and composition. This control directly influences the adsorption properties of the catalyst's surface and the stability of reaction intermediates, thereby enabling enhanced control over reaction pathways and product selectivity. Consequently, the catalytic activity and stability of cobalt-based catalysts can be effectively improved. In the process of preparing cobalt-based catalysts, ILs and DESs can serve as solvents and templates. Owing to the good solubility of ILs and DESs, they can efficiently dissolve raw materials and provide a special nucleation and growth environment, obtaining catalysts with novel-structures. The main focus of this review is to provide a detailed introduction to metal cobalt and its oxide/hydroxide derivatives in the field of water splitting, with a particular emphasis on the research progress achieved through the utilization of IL and DES. The aim is to assist readers in designing and synthesizing novel and high-performance electrochemical catalysts.

Deep Eutectic Solvent as a New Zeta Potential Altering Chemical for Sand Agglomeration

Fines migration can cause various issues, such as plugging of the sand screen and damage to tubings. There are two chemical sand control methods: consolidation and agglomeration. Consolidation works by injection of a solvent into the formation to harden over time and hold the sand in place, while agglomeration works by altering chemical properties of the sand surface to attract and clump up sand. Various chemicals have been used for research in sand control. Some chemicals for consolidation, mostly resins, have been effective in consolidating sand but may cause permeability impairment, which will reduce production. Some chemicals for agglomeration such as a polymer with amines have been less effective or are nonbiodegradable. In this work, a novel deep eutectic solvent (DES) and ionic polymer combination as a fines stabilizer is formulated in-house and tested through extensive experimental study. The development of chemicals is based on agglomeration principles which determine the range of zeta potential reduction that can be achieved to destabilize, coagulate, and flocculate the fine particles together with different combinations of DESs and ionic polymers tested systematically using the design of experiment (DoE) method. The chemicals are then tested for compatibility with reservoir fluids in the jar test. The optimized formulation is characterized by thermogravimetric analysis (TGA) for limit of temperature degradation and laser particle size analysis (LPSA) for the extent of particle size. The novelty of this work is the development of a greener and more cost-saving in-house DES and ionic polymer combination as a fines stabilizer chemical, which is effective for both injection or production wells after stimulation or enhanced oil recovery (EOR) treatments. Due to the tunable nature of the DES, the formulated chemical can be tailored for various reservoir conditions to cater to specific requirements.

Greening Separation and Purification of Proteins and Peptides

The increasing awareness of environmental issues and the transition to green analytical chemistry (GAC) have gained popularity among academia and industry in recent years. One of the principles of GAC is the reduction and replacement of toxic solvents with more sustainable and environmentally friendly ones. This review gives an overview of the advances in applying green solvents as an alternative to the traditional organic solvents for peptide and protein purification and analysis by liquid chromatography (LC) and capillary electrophoresis (CE) methods. The feasibility of using greener LC and CE methods is demonstrated through several application examples; however, there is still plenty of room for new developments to fully realize their potential and to address existing challenges. Thanks to the tunable properties of designer solvents, such as ionic liquids and deep eutectic solvents, and almost infinite possible mixtures of components for their production, it is possible that some new designer solvents could potentially surpass the traditional harmful solvents in the future. Therefore, future research should focus mainly on developing new solvent combinations and enhancing analytical instruments to be able to effectively work with green solvents.

Toward Diverse Plant Proteins for Food Innovation

This review highlights the development of plant proteins from a wide variety of sources, as most of the research and development efforts to date have been limited to a few sources including soy, chickpea, wheat, and pea. The native structure of plant proteins during production and their impact on food colloids including emulsions, foams, and gels are considered in relation to their fundamental properties, while highlighting the recent developments in the production and processing technologies with regard to their impacts on the molecular properties and aggregation of the proteins. The ability to quantify structural, morphological, and rheological properties can provide a better understanding of the roles of plant proteins in food systems. The applications of plant proteins as dairy and meat alternatives are discussed from the perspective of food structure formation. Future directions on the processing of plant proteins and potential applications are outlined to encourage the generation of more diverse plant-based products.

Combining High-Throughput Experiments and Active Learning to Characterize Deep Eutectic Solvents

The high tunability of deep eutectic solvents (DESs) stems from the ease of changing their precursors and relative compositions. However, measuring the physicochemical properties across large composition and temperature ranges, necessary to properly design target-specific DESs, is tedious and error-prone and represents a bottleneck in the advancement and scalability of DES-based applications. As such, active learning (AL) methodologies based on Gaussian processes (GPs) were developed in this work to minimize the experimental effort necessary to characterize DESs. Owing to its importance for large-scale applications, the reduction of DES viscosity through the addition of a low-molecular-weight solvent was explored as a case study. A high-throughput experimental screening was initially performed on nine different ternary DESs. Then, GPs were successfully trained to predict DES viscosity from its composition and temperature, showcasing the ability of these stochastic, nonparametric models to accurately describe the physicochemical properties of complex mixtures. Finally, the ability of GPs to provide estimates of their own uncertainty was leveraged through an AL framework to minimize the number of data points necessary to obtain accurate viscosity modes. This led to a significant reduction in data requirements, with many systems requiring only five independent viscosity data points to be properly described.

A review of greener approaches for rare earth elements recovery from mineral wastes

The use of rare earth elements (REE) in many various fields, including high-tech products, increases the demand for these materials day by day. The production of REE from primary sources has expanded in response to increasing demand; however, due to its limited, a more sustainable supply is also started to offer for the REE demand by using secondary sources. The most commonly used metallurgical method for REE recovery is hydrometallurgical processes. However, it has some disadvantages, like pyrometallurgical methods. In the review, studies of the environmental impacts of REE production from primary sources and life cycle assessments of products containing REE were investigated. According to the results, it has been seen that those studies in the literature in which hydrometallurgical methods have changed to more environmentally friendly approaches have begun to increase. In this review, mine wastes, which are secondary sources, were defined, conventional methods of recovery of rare earth elements were discussed, greener approaches to the recovery of REE from these sources were comprehensively examined and studies in the literature were evaluated. Furthermore, it was stated that there are limited studies on green approaches and REE recovery from mineral wastes and that this field is developing with an emphasis on the current outlook and future perspectives.

Deep eutectic solvent for the extraction of polycyclic aromatic compounds in fuel, food and environmental samples

Polycyclic aromatic compounds (PACs) encompass a wide variety of organic analytes that have mutagenic and carcinogenic potentials for human health and are recalcitrant in the environment. Evaluating PACs levels in fuel (e.g., gasoline and diesel), food (e.g., grilled meat, fish, powdered milk, fruits, honey, and coffee) and environmental (e.g., industrial effluents, water, wastewater and marine organisms) samples are critical to determine the risk that these chemicals pose. Deep eutectic solvents (DES) have garnered significant attention in recent years as a green alternative to traditional organic solvents employed in sample preparation. DES are biodegradable, have low toxicities, ease of synthesis, low cost, and a remarkable ability to extract PACs. However, no comprehensive assessment of the use of DESs for extracting PACs from fuel, food and environmental samples has been performed. This review focused on research involving the utilization of DESs to extract PACs in matrices such as PAHs in environmental samples, NSO-HET in fuels, and bisphenols in foods. Chromatographic methods, such as gas chromatography (GC) and high-performance liquid chromatography (HPLC), were also revised, considering the sensibility to quantify these compound types. In addition, the characteristics of DES and advantages and limitations for PACs in the context of green analytical chemistry principles (GAC) and green profile based on metrics provide perspective and directions for future development.

Determination of fifteen illegal colorants in traditional Chinese medicines by two hydrophobic DES-based microextraction methods coupled with an HPLC-DAD

The dyeing and adulteration of traditional Chinese medicines (TCMs) are continuously updated. Valuable analytical methods for the daily inspection of illegal colorant additives in TCMs and the preparations are in demand. Two deep eutectic solvent (DES)-based vortex-assisted liquid-liquid microextraction (VA-LLME) and ultrasonic-assisted solid-liquid microextraction (UA-SLME) were developed for the sample pretreatment of ten water-soluble colorants and five water-insoluble colorants, respectively, followed by an HPLC-DAD detection. Fifteen colorants were analyzed at four detection wavelengths within 40 min of gradient elution. The optimal DES of VA-LLME and UA-SLME were screened from 23 homemade DESs. The factors affecting the extraction efficiency of VA-LLME and UA-SLME were optimized systematically. Under the optimal conditions, ten water-soluble colorants analyzed by DES-based VA-LLME-HPLC-DAD showed good linearity (R ≥ 0.9995) within the optimal linear range. The LODs and LOQs were 0.2-1.0 μg g-1 and 0. 5-5.0 μg g-1, respectively. The recoveries of spiked samples were 80.2%-104.7 %, with RSDs ≤ 4.39 %. Five water-insoluble colorants of Sudan I‒IV and Sudan 7B analyzed by DES-based UA-SLME-HPLC-DAD showed good linearity (R ≥ 0.9995) within the optimal linear range. The LODs and LOQs were 0.8-8.0 μg g-1 and 4.0-40.0 μg g-1, respectively. The recoveries of spiked samples were 94.2%-103.1 %, with RSDs ≤ 4.81 %. The proposed DES-based VA-LLME-HPLC-DAD was successfully applied to analyze six water-soluble yellow colorants in Cuscutae Semen, salted Cuscutae Semen, and four water-soluble red colorants in Schisandrae Chinensis Fructus. The proposed DES-based UA-SLME-HPLC-DAD was successfully applied to analyze five water-insoluble red colorants in Dieda pills. The study provides analytical method options for routine tests of water-soluble, water-insoluble, or both water-soluble/-insoluble illegal colorant additives in herbal medical materials and preparations by the relevant proposed DES-based sample pretreatment method or a combination of the two proposed DES-based methods.

Green Approaches for the Extraction of Banana Peel Phenolics Using Deep Eutectic Solvents

Banana peels, comprising about 35% of the fruit's weight, are often discarded, posing environmental and economic issues. This research focuses on recycling banana peel waste by optimizing advanced extraction techniques, specifically microwave-assisted (MAE) and ultrasound-assisted extraction (UAE), for the isolation of phenolic compounds. A choline chloride-based deep eutectic solvent (DES) with glycerol in a 1:3 ratio with a water content of 30% (w/w) was compared to 30% ethanol. Parameters, including sample-to-solvent ratio (SSR), extraction time, and temperature for MAE or amplitude for UAE, were varied. Extracts were analyzed for hydroxycinnamic acid (HCA) and flavonoid content, and antioxidant activity using FRAP and ABTS assays. DES outperformed ethanol, with HCA content ranging from 180.80 to 765.92 mg/100 g and flavonoid content from 96.70 to 531.08 mg/100 g, accompanied by higher antioxidant activity. Optimal MAE conditions with DES were an SSR of 1:50, a temperature of 60 °C, and a time of 10 min, whereas an SSR of 1:60, time of 5 min, and 75% amplitude were optimal for UAE. The polyphenolic profile of optimized extracts comprised 19 individual compounds belonging to the class of flavonols, flavan-3-ols, and phenolic acids. This study concluded that DESs, with their superior extraction efficiency and environmental benefits, are promising solvents for the extraction of high-value bioactive compounds from banana peels and offer significant potential for the food and pharmaceutical industries.

Deep Eutectic Solvents for Extraction and Preconcentration of Organic and Inorganic Species in Water and Food Samples: A Review

Deep eutectic solvents (DESs) have been developed as green solvents and these are capable as alternatives to conventional solvents used for the extraction of organic and inorganic species from food and water samples. The continuous generation of contaminated waste and increasing concern for the human health and environment have compelled the scientific community to investigate more ecological schemes. In this concern, the use of DESs have developed in one of the chief approach in the field of chemistry. These solvents have appeared as a capable substitute to conventional hazardous solvents and ionic liquids. The DESs has distinctive properties, easy preparation and components availability. It is not only used in scienctific fields but also used in quotidian life. There are many advantages of DESs in analytical chemistry, they are largely used for extraction and determination of inorganic and organic compounds from different samples. In previous a few years, several advanced researches have been focused on the separation and preconcentration of low level of pollutants using DESs as the extractants. This review summarizes the use of DESs in the separation and preconcentration of organic and inorganic species from water and food samples using various microextraction processes.

Composition of Sphagnum palustre L. extracts using different extraction methods

Sphagnum palustre L. is a Chinese herbal medicine with a long history, however, few studies have been performed on its chemical composition and active effects. In this study, we investigated the composition and antibacterial and antioxidant capacities of extracts obtained from Sphagnum palustre L. phytosomes extracted with conventional solvents (water, methanol, and ethanol) and two different hydrogen bond donors (citric acid and 1,2-propanediol) modified with choline chloride-type deep eutectic solvents (DESs). The results show that Sphagnum palustre extracts contained 253 compounds, including citric acid, ethyl maltol, and thymol. The highest total phenolic content (TPC) was obtained with a DES extraction method combining 1,2-propanediol and choline chloride (39.02 ± 7.08 mg gallic acid equivalent/g dried weight (DW). This shows the composition of Sphagnum palustre as a natural product and the application of DESs in the extraction of active ingredients, demonstrating the potential of peat moss extracts in cosmetics and health products.

Efficient removal of Chromium(VI) from wastewater based on magnetic multiwalled carbon nanotubes coupled with deep eutectic solvents

Industrial wastewater containing heavy metal Cr(VI) seriously affects the health of organisms and may even lead to cancer. Developing efficient adsorbents that can quickly separate heavy metals is crucial for treating wastewater. In this study, magnetic multiwalled carbon nanotubes (MMWCNTs) with moderate particle size and abundant surface active sites were prepared by coating multiwalled carbon nanotubes with magnetic nanoparticles. The results of FTIR, XRD, TG, VSM, BET, and EDS showed MWCNTs completely encapsulated on the surface of the magnetic nanoparticles, with a particle size of approximately 30 nm. Oxygenated groups provided abundant surface active sites and formed numerous mesopores. The response surface methodology was used to optimize the adsorbent dose, adsorption contact time and adsorption temperature, and the removal rate of Cr(VI) was more than 95%. The quasi-second order kinetics and Freundlich adsorption isotherm model explained the adsorption process to Cr(VI). MMWCNTs interacted with Cr(VI) through electrostatic attraction, reduction reactions, complexation, and other means. The extensive hydrogen bonding of the green solvent deep eutectic solvent (DES) was employed to desorb the MMWCNTs and desorption rate exceed 90%. Even after five adsorption-regeneration cycles, the adsorbent maintained a high capacity. In conclusion, these novel MMWCNTs, as efficient adsorbents paired with DES desorption, hold broad potential for application in the treatment of Cr(VI)-contaminated wastewater.

Strategies for using magnetic beads in enhanced deep eutectic solvent-mechanochemical extraction of natural products from orange peels

To address the challenges of low recovery, prolonged extraction times, and environmental pollution caused by toxic solvents in traditional extraction methods, magnetic bead-enhanced deep eutectic solvent mechanochemical extraction was developed for extracting natural products from orange peels. The extraction efficiencies of deep eutectic solvents were experimentally evaluated, and theoretical methods were used to guide solvent selection. Choline chloride-ethylene glycol demonstrated the highest efficiency under the optimal extraction conditions: a molar ratio of 1:2, no water content, a solid-liquid ratio of 0.08 g/mL, and an extraction time of 60 s. The synergy between the deep eutectic solvent and magnetic bead-enhanced the mechanochemical extraction efficiencies. The study also examined the effects of different magnetic bead types and orange peel powder particle sizes on extraction efficiency, finding that a 0.11 mm particle size combined with CIP@SiO2 yielded the best results. Overall, this study holds promise as an environmentally friendly and efficient extraction method.

Valorization and protection of anthocyanins from strawberries (Fragaria×ananassa Duch.) by acidified natural deep eutectic solvent based on intermolecular interaction

This study introduces an innovative approach for the valorization and protection of anthocyanins from 'Benihoppe' strawberry (Fragaria × ananassa Duch.) based on acidified natural deep eutectic solvent (NADES). Choline chloride-citric acid (ChCl-CA, 1:1) was selected and acidified to enhance the valorization and protection of anthocyanins through hydrogen bond. The optimal conditions (ultrasonic power of 318 W, extraction temperature of 61 °C, liquid-to-solid ratio of 33 mL/g, ultrasonic time of 19 min), yielded the highest anthocyanins of 1428.34 μg CGE/g DW. UPLC-Triple-TOF/MS identified six anthocyanins in acidified ChCl-CA extract. Stability tests indicated that acidified ChCl-CA significantly increased storage stability of anthocyanins in high temperature and light treatments. Molecular dynamics results showed that acidified ChCl-CA system possessed a larger diffusion coefficient (0.05 m2/s), hydrogen bond number (145) and hydrogen bond lifetime (4.38 ps) with a reduced intermolecular interaction energy (-1329.74 kcal/mol), thereby efficiently valorizing and protecting anthocyanins from strawberries.

Determination of pesticide residues in soybeans using QuEChERS followed by deep eutectic solvent-based DLLME preconcentration prior to gas chromatography-mass spectrometry analysis

A reliable and greener alternative to the usual extraction methods is reported for the determination of pesticide residues in soybeans. This novel approach combines the classical QuEChERS extraction method with a DLLME (dispersive liquid-liquid microextraction) step, utilizing a deep eutectic solvent (DES) - camphor: hexanoic acid (1:1 molar ratio) - as the microextraction solvent. This DES has never been employed in pesticide analysis by gas chromatography-mass spectrometry of complex matrices like soybeans. A Plackett-Burman screening design was employed to optimize sample preparation variables of QuEChERS (amount of sodium chloride and magnesium sulfate, and amount of PSA and C18 sorbents) and DLLME (pH of medium, amount of sodium chloride, and volume of microextraction solvent). This design allowed for a systematic evaluation of the impact of each parameter on the method's performance. The optimized method was evaluated using a certified reference material and commercial samples of soybeans. The method exhibited high accuracy and precision for most of the analytes under study, demonstrating its applicability for pesticide residue analysis in soybeans. To assess the greenness and practicality of the developed method, the Analytical Greenness (AGREE) and Blue Applicability Grade Index (BAGI) metric systems were employed, respectively. Overall, the proposed QuEChERS-DLLME method using a DES solvent is a reliable and greener alternative to conventional extraction methods for the determination of pesticide residues in soybeans. Its high performance, coupled with its environmental friendliness, makes it a promising tool for food safety analysis.

An Innovative Vortex-Assisted Liquid-Liquid Microextraction Approach Using Deep Eutectic Solvent: Application for the Spectrofluorometric Determination of Rhodamine B in Water, Food and Cosmetic Samples

A new green and highly sensitive method for the determination of rhodamine B (RhB) by deep eutectic solvent-based vortex-assisted liquid-liquid microextraction with fluorescence detection (DES-VALLME-FLD) was developed. The extraction efficiency of conventional solvents and different deep eutectic solvent (DES) systems composed of tetrabutylammonium bromide (TBAB) and an alcohol (hexanol, octanol, or decanol) in different ratios were compared. DFT calculations of intermolecular electrostatic and non-covalent interactions of the most stable RhB forms with DES and water explain the experimental DESs' extraction efficiency. Semiempirical PM7 computations were used to obtain Hansen solubility parameters, which supported the good solubility of the monocationic RhB form in selected DESs. The dependence of the linear calibration of microextraction into 100 µL DES was observed in the RhB calibration range from 0.2 to 10.0 µg L-1 with a correlation coefficient of R2 = 0.9991. The LOD value was calculated to be 0.023 µg L-1. The accuracy and precision of the proposed method were verified over two days with RSD values of 2.9 to 4.1% and recovery of 94.6 to 103.7%. The developed method was applied to the determination of RhB in real samples (tap water, energy drink, and lipstick).

Aroma determination in alcoholic beverages: Green MS-based sample preparation approaches

Aroma determination in alcoholic beverages has become a hot research topic due to the ongoing effort to obtain quality products, especially in a globalized market. Consumer satisfaction is mainly achieved by balancing several aroma compounds, which are mixtures of numerous volatile molecules enclosed in challenging matrices. Thus, sample preparation strategies for quality control and product development are required. They involve several steps including copious amounts of hazardous solvents or time-consuming procedures. This is bucking the trend of the ever-increasing pressure to reduce the environmental impact of analytical chemistry processes. Hence, the evolution of sample preparation procedures has directed towards miniaturized techniques to decrease or avoid the use of hazardous solvents and integrating sampling, extraction, and enrichment of the targeted analytes in fewer steps. Mass spectrometry coupled to gas or liquid chromatography is particularly well suited to address the complexity of these matrices. This review surveys advancements of green miniaturized techniques coupled to mass spectrometry applied on all categories of odor-active molecules in the most consumed alcoholic beverages: beer, wine, and spirits. The targeted literature consider progresses over the past 20 years.

Deep eutectic solvent extraction of myricetin and antioxidant properties

In this study, a response surface method (RSM) was used to optimise the ultrasonic-assisted deep eutectic solvent (DES) extraction of myricetin from myricetin leaves. The results demonstrated that the DES-5 (choline chloride-oxalic acid) system exhibited better extraction results than the other seven DESs prepared. The optimum extraction conditions for myricetin were a DES-5 system with 19% water content of DES, a liquid-to-solid ratio of 37 : 1 mL g-1, an extraction time of 45 min, and an extraction temperature of 72 °C. Under these conditions, the extraction amount of myricetin was 22.47 mg g-1. To optimise the extraction process, the crude myricetin extract was purified, and the optimal conditions were as follows: an AB-8 macroporous adsorption resin was used with an anhydrous ethanol desorption agent. The adsorption rate was 1 BV per h (bed volume per hour), the desorption rate was 1 BV per h, and the desorption capacity was 2 BV (bed volume). The antioxidant properties of the myricetin were also investigated. The results demonstrated that, with an increase in concentration, the scavenging rates of DPPH and ˙OH free radicals increased. Compared to Vc, myricetin had a better scavenging ability for DPPH free radicals, whereas purified myricetin had a better antioxidant effect. At the same concentration, the radical-scavenging rate of the ˙OH radical was slightly higher in myricetin purified by the macroporous adsorption resin than in Vc, and that of the unpurified myricetin was the smallest. Myricetin was purified using a macroporous adsorption resin to improve its antioxidant properties.

A Comprehensive Analysis of Diversity, Structure, Biosynthesis and Extraction of Biologically Active Tannins from Various Plant-Based Materials Using Deep Eutectic Solvents

This paper explores the emerging subject of extracting tannins from various plant sources using deep eutectic solvents (DESs). Tannins are widely used in the food and feed industries as they have outstanding antioxidant qualities and greatly enhance the flavor and nutritional content of a wide range of food products. Organic solvents are frequently used in traditional extraction techniques, which raises questions about their safety for human health and the environment. DESs present a prospective substitute because of their low toxicity, adaptability, and environmental friendliness. The fundamental ideas supporting the application of DESs in the extraction of tannins from a range of plant-based materials frequently used in daily life are all well covered in this paper. Furthermore, this paper covers the impact of extraction parameters on the yield of extracted tannins, as well as possible obstacles and directions for future research in this emerging subject. This includes challenges such as high viscosity, intricated recovery of compounds, thermal degradation, and the occurrence of esterification. An extensive summary of the diversity, structure, biosynthesis, distribution, and roles of tannins in plants is given in this paper. Additionally, this paper thoroughly examines various bioactivities of tannins and their metabolites.

Ultrasound-Assisted Extraction of Phenolic Compounds from Celtuce (Lactuca sativa var. augustana) Leaves Using Natural Deep Eutectic Solvents (NADES): Process Optimization and Extraction Mechanism Research

Natural deep eutectic solvents (NADESs), as emerging green solvents, can efficiently extract natural products from natural resources. However, studies on the extraction of phenolic compounds from celtuce (Lactuca sativa var. augustana) leaves (CLs) by NADESs are still lacking. This study screened the NADES L-proline-lactic acid (Pr-LA), combined it with ultrasound-assisted extraction (UAE) to extract phenolic compounds from CLs, and conducted a comparative study on the extraction effect with traditional extraction solvents. Both SEM and FT-IR confirmed that Pr-LA can enhance the degree of fragmentation of cell structures and improve the extraction rate of phenolic compounds. Molecular dynamics simulation results show that Pr-LA can improve the solubility of phenolic compounds and has stronger hydrogen bonds and van der Waals interactions with phenolic compounds. Single-factor and Box-Behnken experiments optimized the process parameters for the extraction of phenolic compounds from CLs. The second-order kinetic model describes the extraction process of phenolic compounds from CLs under optimal process parameters and provides theoretical guidance for actual industrial production. This study not only provides an efficient and green method for extracting phenolic compounds from CLs but also clarifies the mechanism of improved extraction efficiency, which provides a basis for research on the NADES extraction mechanism.

Green and Efficient Extraction of Phenolic Components from Plants with Supramolecular Solvents: Experimental and Theoretical Studies

The supramolecular solvent (SUPRAS) has garnered significant attention as an innovative, efficient, and environmentally friendly solvent for the effective extraction and separation of bioactive compounds from natural resources. However, research on the use of a SUPRAS for the extraction of phenolic compounds from plants, which are highly valued in food products due to their exceptional antioxidant properties, remains scarce. The present study developed a green, ultra-sound-assisted SUPRAS method for the simultaneous determination of three phenolic acids in Prunella vulgaris using high-performance liquid chromatography (HPLC). The experimental parameters were meticulously optimized. The efficiency and antioxidant properties of the phenolic compounds obtained using different extraction methods were also compared. Under optimal conditions, the extraction efficiency of the SUPRAS, prepared with octanoic acid reverse micelles dispersed in ethanol-water, significantly exceeded that of conventional organic solvents. Moreover, the SUPRAS method demonstrated greater antioxidant capacity. Confocal laser scanning microscopy (CLSM) images revealed the spherical droplet structure of the SUPRAS, characterized by a well-defined circular fluorescence position, which coincided with the position of the phenolic acids. The phenolic acids were encapsulated within the SUPRAS droplets, indicating their efficient extraction capacity. Furthermore, molecular dynamics simulations combined with CLSM supported the proposed method's mechanism and theoretically demonstrated the superior extraction performance of the SUPRAS. In contrast to conventional methods, the higher extraction efficiency of the SUPRAS can be attributed to the larger solvent contact surface area, the formation of more types of hydrogen bonds between the extractants and the supramolecular solvents, and stronger, more stable interaction forces. The results of the theoretical studies corroborate the experimental outcomes.

Developing of an eco-friendly liquid-liquid microextraction method by using menthol-based hydrophobic deep eutectic solvent for determination of basic fuchsin dye: assessment of the greenness profile

Herein, we aimed to develop a new environmentally friendly liquid-liquid microextraction (LLME) method based on hydrophobic deep eutectic solvent (hDES) synthesized using biodegradable dl-menthol and decanoic acid for the spectrophotometric determination of toxic basic fuchsin dye in environmental water samples. The parameters affecting the extraction efficiency such as pH, mole ratio, and volume of hDES (1:2) and type and volume of organic solvent, sample volume, times of vortex, ultrasonic bath and centrifuge, ionic strength, and matrix effect were investigated and optimized. Under optimal conditions, the calibration curve showed linearity in the range of 7.4-167 μg L-1 with a coefficient of determination of 0.9994. The limit of detection, intra-day and inter-day precision, and recovery values were 2.25 μg L-1, 2.46% and 4.45%, and 105 ± 3%, respectively. The preconcentration and enrichment factors were found to be 30 and 61.5, respectively. The proposed hDES-LLME methodology was successfully applied to the environmental water samples to detect toxic BF dye (95-105%). Finally, the ecological impact of the suggested method was evaluated using the analytical eco-scale (PPS:88), complementary green analytical procedure indexe (ComplexGAPI), and the Analytical GREEnness tool (0.63). The assessment results showed that the presented analytical method can be regarded as a green LLME approach for the determination of the BF in water.

Solute dynamics of a hydrophobic molecule in a menthol-thymol based type-V deep eutectic solvent: effect of composition of the components

Type-V deep eutectic solvents (DESs) are a newly emerging unique class of solvents obtained by physical mixing and heating of non-ionic components. These solvents show deviation from the thermodynamic ideality. Compared to type-I to IV DESs, type-V DESs are less explored and their physical chemistry is in its nascent stage. In this work, we have chosen a type-V DES based on menthol-thymol (MT) for our working media. Solvent and rotational dynamics were studied with varying temperature using a well-known solvatochromic probe, Coumarin 153 (C153). We prepared the MT-based DES using a reported procedure at three molar ratios: 1 : 1 (M1T1), 1 : 1.5 (M1T1.5), and 2 : 1 (M2T1) of menthol (M) and thymol (T). Time-resolved emission spectra (TRES) were constructed with varying temperature. Utilizing TRES, the decay of the solvent correlation function (C(t)) was plotted. We have correlated the solvent relaxation time in these DESs as a function of viscosity. The time-resolved anisotropy decays were also collected to perceive the rotational relaxation dynamics of C153 as a function of temperature. The decay of solvent relaxation was found to be bi-exponential, and the average solvation time (〈τs〉) in M2T1 was found to be longer than those of M1T1.5 and M1T1. The rotational reorientation times (〈τrot〉) also follow the same trend. We have analysed the rotational dynamics of C153 in type-V DESs employing the Stokes-Einstein-Debye (SED) hydrodynamic model. The rotational dynamics in DESs demonstrate a good correlation with the SED model with a little deviation. In MT-based DESs, the solute's rotational relaxation times approach hydrodynamic stick boundary condition at low viscosity (or at high temperatures) for all molar compositions. Using the Arrhenius-type equations, we have correlated the activation energies for the rotational motion of C153, along with the viscous flow and non-radiative pathways for all the DESs.

Recent progress in promoting the bioavailability of polyphenols in plant-based foods

Polyphenols are important constituents of plant-based foods, exhibiting a range of beneficial effects. However, many phenolic compounds have low bioavailability because of their low water solubility, chemical instability, food matrix effects, and interactions with other nutrients. This article reviews various methods of improving the bioavailability of polyphenols in plant-based foods, including fermentation, natural deep eutectic solvents, encapsulation technologies, co-crystallization and amorphous solid dispersion systems, and exosome complexes. Several innovative technologies have recently been deployed to improve the bioavailability of phenolic compounds. These technologies may be utilized to increase the healthiness of plant-based foods. Further research is required to better understand the mechanisms of action of these novel approaches and their potential to be used in food production.

Polysaccharides extraction from Ganoderma lucidum using a ternary deep eutectic solvents of choline chloride/guaiacol/lactic acid

In this study, a purposefully formulated ternary deep eutectic solvents (DESs), consisting of choline chloride, guaiacol, and lactic acid in a molar ratio of 1:1:1, was synthesized for the extraction of polysaccharides from Ganoderma lucidum. The physicochemical properties of the synthesized DESs, including viscosity, density, pH, and hydrogen bonds, were comprehensively examined. Verification of the formation of the ternary DESs was accomplished through Fourier transform infrared and Nuclear magnetic resonance spectroscopies. Subsequently, response surface methodology was applied to optimize crucial parameters for polysaccharide extraction using DESs, resulting in a maximal extraction yield of 94.72 mg/g under the optimized conditions. Cyclic experiments demonstrated the commendable cyclic stability of the DESs, with a recovery rate exceeding 88 %. Furthermore, experiments on monosaccharide composition, molecular weight, and antioxidant activity of the isolated polysaccharides were conducted. Density functional theory was employed to gain insights into the molecular mechanism of polysaccharide extraction by DESs. The findings revealed a triple hydrogen bond interaction and a high binding energy (65.29 kcal/mol) between the DESs and glucose, highlighting their significant contribution to the high extraction effectiveness. This molecular-level understanding underscores the inherent superiority of DESs in the polysaccharide extraction processes, providing valuable insights for future applications in this field.

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.