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.
Supramolecular solvent (SUPRAS) extraction is gaining attraction as a sample treatment technique because of its great performance in terms of effectiveness, versatility, sample clean-up, quickness, ...cost and sustainability. However, the nature of SUPRASs, being formed by amphiphile molecules, results in poor compatibility with Gas Chromatography (GC). Here, we show the hitherto unexplored development of a SUPRAS with high thermal stability (HTS) suitable for subsequent direct analysis by Headspace (HS)-GC. This novel HTS-SUPRAS, based on poly-undecylenic acid -an oligomeric surfactant-, tetraglyme -a polar aprotic solvent with excellent chemical and thermal stability- and water, was fully characterized in terms of composition and physical properties such as thermal stability. Subsequently, the HTS-SUPRAS developed was further successfully applied, as a proof-of-principle, to the extraction and determination of residual solvents in pharmaceutical drugs, including several solvents (class 2C) whose analysis by HS-GC has been shown to be highly complex. Analytical performance was demonstrated as mandated by the International Council for Harmonisation of technical requirements for pharmaceuticals for human use (ICH). Furthermore, excellent recoveries (70–120%) and high precisions (<20%, expressed as relative standard deviations) were obtained for the analysis of several different drug formulations spiked with the analyzed 37 residual solvents at their respective maximum residue levels.
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•A supramolecular solvent with high thermal stability is described for the first time.•This new solvent is based on poly-undecylenic acid, an oligomeric surfactant.•It opens a new avenue for sample treatment prior to Headspace - Gas Chromatography.•A validated determination of 37 residual solvents in 10 different drugs was achieved.
Large amounts of agri-food by-products, non-edible food, and waste are produced throughout the supply chain from the initial production to the final consumption stages. The valorization of this ...biomass to obtain high value-added compounds has been the focus of extensive research in the last decade. For this purpose, the use of green techniques is essential to reduce the negative impact on the health and the environment. In this review, we discuss the use of green solvents for the valorization of agri-food waste and by-products, and we consider their potential to replace conventional organic solvents in order to provide more environmentally friendly and sustainable processes. The use of supercritical fluids, neoteric (ionic liquids and deep eutectic solvents), bio-based, and supramolecular solvents is critically dicussed. Parameters affecting extraction efficiency are detailed for each type of solvent along with advantages and limitations for application at the industrial scale.
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