Phlorotannins are secondary metabolites produced mainly by brown seaweeds (Phaeophyceae) and belong to the class of polyphenolic compounds with diverse bioactivities. The key factors in the ...extraction of polyphenols are the selection of a suitable solvent, method of extraction and selection of optimal conditions. Ultrasonic-assisted extraction (UAE) is one of the advanced energy-saving methods suitable for the extraction of labile compounds. Methanol, acetone, ethanol and ethyl acetate are the most commonly used solvents for polyphenol extraction. As alternatives to toxic organic solvents, a new class of green solvents, natural deep eutectic solvents (NADES), has been proposed for the efficient extraction of a wide range of natural compounds including polyphenols. Several NADES were screened previously for the extraction of phlorotannins; however, the extraction conditions were not optimized and chemical profiling of NADES extract was not performed. The purpose of this work was to study the effect of selected extraction parameters on the phlorotannin content in NADES extract from
optimization of extraction conditions and chemical profiling of phlorotannins in the NADES extract. A fast and green NADES-UAE procedure was developed for the extraction of phlorotannins. Optimization was performed through an experimental design and showed that NADES (lactic acid:choline chloride; 3:1) provides a high yield (137.3 mg phloroglucinol equivalents per g dry weight of algae) of phlorotannins under the following extraction conditions: extraction time 23 min, 30.0% water concentration and 1:12 sample to solvent ratio. The antioxidant activity of the optimized NADES extract was equal to that of EtOH extract. In total, 32 phlorotannins have been identified (one trimer, two tetramers, six pentamers, four hexamers, six heptamers, six octamers and seven nonamers) in NADES extracts from arctic
using the HPLC-HRMS and MS/MS technique. It was noted that all the above-mentioned phlorotannins were identified in both EtOH and NADES extracts. Our results suggest that NADES could be considered as an alternative to the conventional techniques for the effective extraction of phlorotannins from
with high antioxidant potential.
Deep eutectic solvents have emerged in green chemistry only seventeen years ago and yet resulted in a plethora of publications covering various research areas and diverse fields of application. Deep ...eutectic solvents appear as promising alternatives to conventional organic solvents due to their straightforward preparation using highly accessible and natural compounds. They display also high tunability. Here we present the classification and preparation methods of deep eutectic solvents. We detail their physicochemical properties such as phase behavior, density, viscosity, ionic conductivity, surface tension, and polarity. Properties are controlled by the choice of the forming compounds, molar ratio, temperature, and water content.
The concept of sustainable development has impacted in analytical chemistry changing the way of thinking processes and methods. It is important for analytical chemists to consider how sample ...preparation can integrate the basic concepts of Green Chemistry. In this sense, the replacement of traditional organic solvents is of utmost importance. Natural Deep Eutectic Solvents (NADES) have come to light as a green alternative. In the last few years, a growing number of contributions have applied these natural solvents proving their efficiency in terms of extraction ability, analyte stabilization capacity and detection compatibility. However, the arising question that has to be answered is: the use of NADES is enough to green an extraction process? This review presents an overview of knowledge regarding sustainability of NADES-based extraction procedures, focused on reported literature within the timeframe spanning from 2011 up to date. The contributions were analyzed from a green perspective in terms of energy, time, sample and solvent consumption. Moreover, we include a critical analysis to clarify whether the use of NADES as extraction media is enough for greening an analytical methodology; strategies to make them even greener are also presented. Finally, recent trends and future perspectives on how NADES-based extraction approaches in combination with computational methodologies can contribute are discussed.
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•Contributions regarding NADES as extraction media are analyzed in terms of energy, time, sample and solvent consumption.•Strategies to make NADES-mediated approaches even greener are presented.•The review underlines the relevance of developing sustainable analytical methodologies.
Ultrasound-assisted extraction is a common technique for the extraction of organic contaminants from solid samples due to its ease of application to a variety of matrices and the wide range of ...solvents that can be used. In recent years, many methods have combined sonication with microextraction techniques for liquid samples. Among the improvements in extraction techniques, there is an increasing interest in reducing the use of traditional organic solvents or replacing them with other less toxic solvents, such as ionic liquids due to the negligible vapour pressure of these solvents. However, these solvents are not fully green due to poor biodegradability and some toxicity to aquatic life. As a result of the growing interest in the so-called “Green Chemistry”, the use of more environmentally friendly solvents, such as deep eutectic solvents, or novel sorbents, such as magnetic nanoparticles, has been observed for the extraction of organic contaminants. This review provides an overview of the new applications of ultrasound-assisted extraction for the determination of organic contaminants, with special emphasis on the methods that implement the principles of Green Analytical Chemistry to reduce the environmental impact. In this article, the ultrasound-assisted extraction methods proposed in the last five years (2018–2022) are reviewed to update our previous review.
•Overview of new applications of ultrasound assisted extraction from 2018 to 2022.•Ultrasound-assisted extraction methods for organic contaminants are discussed.•Microextraction methods for liquid samples are summarized.•Application of new sorbents and green solvents is discussed.
Deep eutectic solvent (DES) is regarded as a new generation of green solvent due to its distinctive and tailorable physicochemical properties, such as low volatility, strong solubility, ...biodegradability, low-cost, environment-friendly, and feasibility of the structural design. As an alternative to traditional organic solvents and ionic liquids (ILs), DESs have been widely applied in many fields, such as organic chemical synthesis, electrochemical deposition, material preparation, biomass catalytic conversion, extraction and separation, detection and analysis, nanotechnology, gas absorption, and drug delivery. In this paper, through in-depth discussion on factors influencing the physicochemical properties of DESs, we summarized the relations between their composition, structure, and performance. Focusing on their solvent performance, we analyzed the latest research results of DESs with different physicochemical properties in various fields. It should be pointed out that designing and synthesizing DESs from the molecular structure aspect to regulate their physicochemical properties is the direction of accurately developing new functional applications of DESs.
Natural phenolic compounds are important classes of plant, microorganism, and algal secondary metabolites. They have well-documented beneficial biological activities. The marine environment is less ...explored than other environments but have huge potential for the discovery of new unique compounds with potential applications in, e.g., food, cosmetics, and pharmaceutical industries. To survive in a very harsh and challenging environment, marine organisms like several seaweed (macroalgae) species produce and accumulate several secondary metabolites, including marine phenolics in the cells. Traditionally, these compounds were extracted from their sample matrix using organic solvents. This conventional extraction method had several drawbacks such as a long extraction time, low extraction yield, co-extraction of other compounds, and usage of a huge volume of one or more organic solvents, which consequently results in environmental pollution. To mitigate these drawbacks, newly emerging technologies, such as enzyme-assisted extraction (EAE), microwave-assisted extraction (MAE), ultrasound-assisted extraction (UAE), pressurized liquid extraction (PLE), and supercritical fluid extraction (SFE) have received huge interest from researchers around the world. Therefore, in this review, the most recent and emerging technologies are discussed for the extraction of marine phenolic compounds of interest for their antioxidant and other bioactivity in, e.g., cosmetic and food industry. Moreover, the opportunities and the bottleneck for upscaling of these technologies are also presented.
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•A systematic assessment on both toxicity and biodegradability of DESs.•DESs cannot be simply regarded as nontoxic or readily biodegradable.•Strong relationship between ...toxicity/biodegradability of DESs and their structures.•Toxicity of DES components can be drastically lowered by incorporation into DES.•Toxicity mechanism may be related to interactions of DESs with cellular membranes.
Deep eutectic solvents (DESs) have emerged as a new type of promising ionic solvents with a broad range of potential applications. Although their ecotoxicological profile is still poorly known, DESs are generally regarded as “green” because they are composed of ammonium salts and H-bond donors (HBDs) which are considered to be eco-friendly. In this work, cholinium-based DESs comprised of choline chloride (ChCl) and choline acetate (ChAc) as the salt and urea (U), acetamide (A), glycerol (G) and ethylene glycol (EG) as the HBD were evaluated for their toxic effects on different living organisms such as Escherichia coli (a bacterium), Allium sativum (garlic, a plant) and hydra (an invertebrate), and their biodegradabilities were assessed by means of closed bottle tests. These DESs possessed an anti-bacterial property and exhibited inhibitory effects on the test organisms adopted, depending on the composition and concentration of the DES. The mechanism for the impact of DESs and their components on different living organisms can be associated to their interactions with the cellular membranes. Not all DESs can be considered readily biodegradable. By extending the limited knowledge about the toxicity and biodegradation of this particular solvent family, this investigation on DESs provides insight into our structure-based understanding of their ecotoxicological behavior.
Green solvents reduce secondary pollution of the environment during pesticide pre-concentration in food and environmental matrices. Ionic liquids are among the green solvents that are widely used ...during pesticides analysis. Their physico-chemical properties can be easily modified by changing the cation/anion combinations in their structures. This paper critically reviews the application of ionic liquids during pre-concentration of pesticides in food and environmental samples. Another group of green, designer solvents is composed of deep eutectic solvents. They are synthesised simply by mixing hydrogen bond donors and hydrogen bond acceptors. Their contributions during pesticide pre-concentration are reviewed critically in this paper. The use of supramolecular solvents during pesticide pre-concentration is gaining popularity among researchers. They are green, water-immiscible solvents composed of three-dimensional amphiphilic aggregates and their applications during pesticide pre-concentration are reviewed in this paper. The amount of chemicals used during pesticide analysis can be reduced by using switchable solvents. This paper also gives a critical review of the applications of switchable solvents during micro-extraction of pesticides in food and environmental samples. In addition, the challenges associated with the use of these green solvents are discussed in this review as well as the future prospects.
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•Green solvents can be used during micro-extraction of pesticide residues.•They mitigate secondary pollution of the environment during pesticide analysis.•Some green solvents have adjustable properties during pesticide pre-concentration.•Use of green solvents result in high extraction recoveries and enrichment factors.
Ionic liquids (ILs) and deep eutectic solvents (DESs) debuted with a promise of a superior sustainability footprint due to their low vapor pressure. However, their toxicity and high cost compromise ...this footprint, impeding their real‐world applications. Fortunately, their property tunability through a rational selection of precursors, including bioderived ones, provides a strategy to ameliorate toxicity, lower cost, and endow new functions. This Review discusses whether ILs and DESs are sustainable solvents and how they contribute to sustainable chemical processes.
Ionic liquids (ILs) and deep eutectic solvents (DESs) continue to generate interest within and beyond the chemistry community. Their property tunability through a rational selection of precursors, including bioderived ones, provides a strategy to ameliorate toxicity, lower cost, and endow new functions for sustainable chemistry. This Review discusses whether ILs and DESs are sustainable solvents and how they contribute to sustainable chemical processes.
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