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Abstract

The ever-increasing demand for determining compounds at low concentration levels in complex matrices requires a preliminary step of analytes isolation/enrichment in order to employ a detection technique characterised by high sensitivity at low LOQ. Sample preparation is considered as crucial part of analytical procedures. Previously the parameter of „greenness” is as important as selectivity in order to avoid using harmful organic solvents in sustainable extraction techniques. These solvents can generate hazardous, toxic waste while consuming large resources volume. Developing new green solvents is one of the key subjects in Green Chemistry in order to reduce the intensity of anthropogenic activities related to analytical laboratories. A lot of new, more eco-friendly media have been employed as extractant phases. These media, besides of being more eco-friendly, provide shorter extraction times, simplicity, low cost, better selectivity in some cases. The most promising, most widely used green extraction solvents are described in this review.

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... Volatile organic chemicals are commonly used in many industrial techniques, such as food or pharmaceutical production, or in separation processes [1][2][3][4]. They mainly include organic chemical compounds such as alcohols, aldehydes, ketones, aliphatic and aromatic hydrocarbons with boiling points above 50°C [1]. ...
... They mainly include organic chemical compounds such as alcohols, aldehydes, ketones, aliphatic and aromatic hydrocarbons with boiling points above 50°C [1]. These compounds are often very toxic and flammable [1,4]. With the raising awareness for environmental protection and human health, green solvents are getting more attention as alternative replacement for toxic organic chemicals [1,5]. ...
... low toxicity, minimal viscosity, non-flammability, solute selectivity, etc. [1]. Terpenes, which can be obtained from plants, wood, and algal biomass, represent potentially good candidates as green compounds [2,4,[6][7][8][9]. Commercially, they can find various applications in different industrial fields as flavours, food additives, cosmetics, pharmaceuticals, solvents, biofuels, pesticides [4,[10][11][12][13][14]. ...
Article
An experimental analysis of density, refractive index, speed of sound and the viscosity at atmospheric pressure and temperatures T = (288.15 to 323.15) K has been carried out for the three binary systems, i.e. (p-cymene + α-pinene), (p-cymene + limonene) and (p-cymene + citral). Excess molar volumes, viscosity deviations, deviations in isentropic compressibility and excess Gibbs free energy of activation of viscous flow were calculated from experimental data. The results were fitted employing Redlich-Kister polynomial equation. Also, partial molar volumes, excess partial molar volumes and partial molar volumes at infinite dilutions were calculated to elucidate the non-ideal behavior of investigated mixtures. Furthermore, Prigogine-Flory-Patterson (PFP) model was successfully applied for the correlation of excess molar volumes of examined binary mixtures. The results of excess molar volume correlations show very good agreement with experimental measurement.
... В последнее время в КМЭ вместо токсичных растворителей все чаще применяют экологически чистые растворители, такие как ионные жидкости (ИЖ). Применению ИЖ в КМЭ посвящен отдельный обзор [36] и большие разделы в обзорах [34,42,32,[59][60][61][62][63]. Полезными оказались такие свойства ИЖ, как низкое давление паров, хорошая термическая стабильность, высокая и варьируемая вязкость, большое поверхностное натяжение. ...
... В ряде случаев применение ИЖ позволило не только повысить эффективность экстракции, но и улучшить воспроизводимость результатов. Информацию о применении ИЖ в ММЭ в полое волокно можно найти в обзорах [59][60][61][62]73]. Первые упоминания о применении глубоких эвтетических растворителей в трехфазной ММЭ в полое волокно приведены в обзорах [65,66]. ...
Article
Single-drop microextraction (SDME) and hollow-fiber membrane microextraction (HFME) belong to methods of the liquid-phase microextraction preconcentration of organic compounds. These methods are characterized by the low consumption of organic solvents, high preconcentration factors, simplicity, low cost, ease of combination with various chromatographic methods; processes of preconcentration and sample injection are combined in a single device. Since the emergence of SDME (1996) and HFME (1999), a large number of versions have been developed that differ in the preconcentration technique, nature of the extractants used, and combinations with methods for the subsequent determination of the preconcentrated substances. The popularity of these methods among the analysts is evidenced by many reviews that we have summarized in this publication.
... It is necessary for cannabinoid compounds to be extracted with organic solvents instead of water, because the active compounds are less soluble in polar solvents [41]. The most commonly used solvents are ethanol, ether, chloroform, and methanol [42]. When used for extraction, various compounds, including some undesired substances, dissolve together with the cannabinoids [42]. ...
... The most commonly used solvents are ethanol, ether, chloroform, and methanol [42]. When used for extraction, various compounds, including some undesired substances, dissolve together with the cannabinoids [42]. The high solvent power of ethanol for cannabinoid compounds is the reason why it is frequently used in home-made extracts of Cannabis [41]. ...
Article
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Cannabis sativa is known among many cultures for its medicinal potential. Its complexity contributes to the historical application of various parts of the plant in ethno-medicines and pharmacotherapy. C. sativa has been used for the treatment of rheumatism, epilepsy, asthma, skin burns, pain, the management of sexually transmitted diseases, difficulties during child labor, postpartum hemorrhage, and gastrointestinal activity. However, the use of C. sativa is still limited, and it is illegal in most countries. Thus, this review aims to highlight the biological potential of the plant parts, as well as the techniques for the extraction, isolation, and characterization of C. sativa compounds. The plant produces a unique class of terpenophenolic compounds, called cannabinoids, as well as non-cannabinoid compounds. The exhaustive profiling of bioactive compounds and the chemical characterization and analysis of C. sativa compounds, which modern research has not yet fully achieved, is needed for the consistency, standardization, and the justified application of Cannabis sativa products for therapeutic purposes. Studies on the clinical relevance and applications of cannabinoids and non-cannabinoid phenols in the prevention and treatment of life-threatening diseases is indeed significant. Furthermore, psychoactive cannabinoids, when chemically standardized and administered under medical supervision, can be the legal answer to the use of C. sativa.
... The density of CO 2 can be altered by making very minor changes to temperature and pressure [12]. SFE is considered a greener technique because of its low impact on the environment, and it does not require the use of hazardous organic solvents [13]. SFE has already been commercialized for the extraction of cannabis and related products. ...
... The cannabis strain, "tower" (cannabidiol-dominant), with the sativa genotype was planted on 4 May 2017 under ideal growing conditions (12)(13)(14)(15)(16)(17)(18) h light exposure at 23 • C). The flowers of the cannabis sample were collected at the fluorescence stsgeand dried for 5 to 8 days at 20 • C. According to the certificate of analysis, the flower material had around 15% w/w of CBD and CBDA, whereas THC and THCA levels were around 0.517% w/w. ...
Article
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The optimization of the supercritical fluid extraction (SFE) of cannabinoids, using supercritical carbon dioxide (scCO2), was investigated in a fractional factorial design study. It is hypothesized that four main parameters (temperature, pressure, dry flower weight, and extraction time) play an important role. Therefore, these parameters were screened at predetermined low, medium, and high relative levels. The density of scCO2 was used as a factor for the extraction of cannabinoids by changing the pressure and temperature. The robustness of the mathematical model was also evaluated by regression analysis. The quantification of major (cannabidiol (CBD), cannabidiolic acid (CBDA), delta 9-tetrahydrocannabinol (Δ9-THC), delta 8-tetrahydrocannabinol (Δ8-THC), and delta 9-tetrahydrocannabinol acid (THCA-A)) and minor (cannabidivann (CBDV), tetrahydrocannabivann (THCV), cannabigerolic acid (CBG), cannabigerol (CBGA), cannabinol (CBN), and cannabichomere (CBC)) cannabinoids in the scCO2 extract was performed by RP-HPLC analysis. From the model response, it was identified that long extraction time is a significant parameter to obtain a high yield of cannabinoids in the scCO2 extract. Higher relative concentrations of CBD(A) (0.78 and 2.41% w/w, respectively) and THC(A) (0.084 and 0.048% w/w, respectively) were found when extraction was performed at high relative pressures and temperatures (250 bar and 45 °C). The higher yield of CBD(A) compared to THC(A) can be attributed to the extract being a CBD-dominant cannabis strain. The study revealed that conventional organic solvent extraction, e.g., ethanol gives a marginally higher yield of cannabinoids from the extract compared to scCO2 extraction. However, scCO2 extraction generates a cleaner (chlorophyll-free) and organic solvent-free extract, which requires less downstream processing, such as purification from waxes and chlorophyll.
... Where PFAS (which also have outstanding physico-chemical properties, such as high chemical and thermal stability, but, unlike other persistent organic pollutants (POPs), are amphiphilic) are concerned, methods based on solid-phase extraction (mainly using reverse phase C18 sorbent or ion change sorbents, WAX) or extraction with acetonitrile or methanol are usually employed [18,19]. Unfortunately, most of these methods are very laborious and require a relatively large amount of organic, often toxic solvents, such as dichloromethane, n-hexane, etc. [20,21]. ...
... The modifications usually involve the extraction solvent, with ethyl acetate (EtOAc) being the most widely used for PAHs, PCBs, OCPs, and BFRs eligible for gas chromatography coupled to mass spectrometry (GC-MS) analysis [15,16,22,23]. Both solvents are considered environmentally friendly and therefore their use is very suitable for these methods [20,21]. To minimize the amount of potentially interfering matrix co-extracts present in the crude extracts, dispersive solidphase extraction (dSPE) is widely employed. ...
Article
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Interference of residual lipids is a very common problem in ultratrace analysis of contaminants in fatty matrices. Therefore, quick and effective clean-up techniques applicable to multiple groups of analytes are much needed. Cartridge and dispersive solid-phase extraction (SPE and dSPE) are often used for this purpose. In this context, we evaluated the lipid clean-up efficiency and performance of four commonly used sorbents—silica, C18, Z-Sep, and EMR-lipid—for the determination of organic pollutants in fatty fish samples (10%) extracted using ethyl acetate or the QuEChERS method. Namely, 17 polychlorinated biphenyls (PCBs), 22 organochlorine pesticides (OCPs), 13 brominated flame retardants (BFRs), 19 per- and polyfluoroalkyl substances (PFAS), and 16 polycyclic aromatic hydrocarbons (PAHs) were determined in this study. The clean-up efficiency was evaluated by direct analysis in real time coupled with time-of-flight mass spectrometry (DART-HRMS). The triacylglycerols (TAGs) content in the purified extracts were significantly reduced. The EMR-lipid sorbent was the most efficient of the dSPE sorbents used for the determination of POPs and PAHs in this study. The recoveries of the POPs and PAHs obtained by the validated QuEChERS method followed by the dSPE EMR-lipid sorbent ranged between 59 and 120%, with repeatabilities ranging between 2 and 23% and LOQs ranging between 0.02 and 1.50 µg·kg−1.
... As a result, each solvent is labeled with a color, such as green, yellow, or red, and a description, such as "recommended," "to be confirmed," "problematic," or "dangerous." [5]. ...
... The majority of LC solvents are volatile organic chemicals that permeate directly into the environment toxicity. A solvent-replacement approach is currently one of the main areas of focus being explored in greening chromatography, in which the most common mobile phases containing acetonitrile and/or methanol are replaced by less harmful and more ecofriendly supercritical alternatives, such as water and ethanol or isopropanol [5][6][7]. ...
Article
The environmental impact of analytical procedures is a major concern nowadays. As a result, scientists are now working to reduce the adverse environmental impact of chemicals and solvents. Stability testing is an important stage in the pharmaceutical industry because it determines how a drug product's quality changes over time as a result of environmental and laboratory conditions. This study demonstrates the use of green reversed phase (RP-HPLC) to determine pyridoxine HCl (PYR) and doxylamine succinate (DOX) in the presence of DOX oxidative degradation product (DOX DEG). DOX DEG was identified by using (LC-MS). The chromatographic separation was achieved using a mobile phase consisting of ethanol and 0.01M phosphate buffer pH=5.0 (10: 90, v/v) with isocratic elution, pumped at 1.0 mL/min on an Xterra C18 column (100 mm x 4.6mm x 5m). DAD was used for detection at 254.0 nm, and the retention times for PYR, DOX, and DOX DEG were 1.41 min, 5.89 min, and 7.36 min, respectively. This procedure was valid over linearity ranges of 10.00-120.00 g/mL and 5.00-100.00 g/mL, with mean percentage recoveries100.09± 0.949 and 100.29±0.519 for PYR and DOX, respectively. The presented chromatographic method was fully validated in accordance with ICH requirements and was statistically compared with those of the reported method and there was no significant difference between them. The proposed approach was shown to be more eco -friendly in terms of the use of hazardous chemicals and solvents, energy consumption, and waste generation than the reported one.
... Therefore, sample purification and enrichment of the targeted analytes in a complex matrix can be one of the main aims of sample analysis methods . In this regard, different types of organic solvents, including esters, ethers, alcohols, aromatic and aliphatic hydrocarbons, halogenated hydrocarbons, aldehydes, and ketones, are mainly applied as extraction or adsorbent solvents (Płotka-Wasylka et al. 2017). It is well known that most of these solvents are highly toxic, flammable, volatile, and detrimental to the environment (Płotka-Wasylka et al. 2017). ...
... In this regard, different types of organic solvents, including esters, ethers, alcohols, aromatic and aliphatic hydrocarbons, halogenated hydrocarbons, aldehydes, and ketones, are mainly applied as extraction or adsorbent solvents (Płotka-Wasylka et al. 2017). It is well known that most of these solvents are highly toxic, flammable, volatile, and detrimental to the environment (Płotka-Wasylka et al. 2017). ...
Chapter
"Microextraction techniques in analytical toxicology" provides the information readers need to include about cutting-edge sample preparation techniques into their everyday analytical practice, including comprehensive information about principle and state-of-art on microextraction sample preparation techniques for analysis of drugs and poisons in biological specimens especially in forensic and clinical settings. The book also focuses on theoretical discussion of solid-based and liquid-based microextraction techniques, their method development, validation, and applications. A detailed compilation of analytical protocols based on published microextraction procedures to aid in method development, synthesis, and application of green solvents (ionic liquids and deep eutectic solvents) and new sorbents such as molecularly imprinted polymers and their application in microextraction techniques are also covered. Features: Provides a systematic review of microextraction techniques applied in analytical toxicology. A comprehensive guide for practical implementation of microextraction techniques in forensic, clinical and analytical laboratories. Contains figures and tables for easy understanding and quick adaptation of parameters of microextraction techniques. Fundamentals, development, and applications of microextraction techniques as a sample preparation procedure are discussed in detail. Extremely useful for the researchers and academicians engaged in the analytical method development using microextraction techniques. This book appeals to a wide readership of forensic, clinical, and analytical toxicologists, academicians, and researchers. Written by eminent scientists and leading experts on sample preparation techniques, this book serves as a desk reference for routine laboratory analysis and an indispensable teaching tool in the classrooms for graduate and Ph.D. students.
... In general, solvents can be selected as extraction solvents that are denser than water, so that in the extraction process they are easily separated from the aqueous phase and deposited. The amount of toxin solubility in these solvents should be higher than water so that the organic phase transfer is facilitated and extraction has a higher efficiency [14]. The lower solubility of these solvents in water leads to higher separation efficiency because the phase separation occurs easily. ...
... The results of pesticide extraction recovery using selective solvents are shown in Figure 7. The dispersive solvent also plays a key role in the DLLME and it acts as a bridge between the extraction solvent and water [14]. ...
... These solvents are liquid below 100 • C and their properties as a solvent are similar to those for ILs. Furthermore, they are denser and more viscous at room temperature than water; their ionic conductivity is rather low; they are biodegradable, non-reactive with water, their production process is simple and cost-effective, many ionic species can be dissolved by this kind of solvents and there is a large number of possible combinations yielding a DES [111]. ...
Article
Full-text available
The use of oils and fats, mainly from non-edible or used sources, microalgae, plastic wastes, and lignocellulosic residues as feedstock to elaborate different kinds of renewable fuels (biodiesel, hydrotreated vegetable oils, pyrolysis oils, and bio-oils) is increasing with the aim of implementing a circular and dynamic economy. Quality control of these materials involves the quantification of trace elements. Their presence, even at trace levels, leads to environmental concerns, fuel instabilities and may impact the performance of combustion engines. Therefore, in order to circumvent these problems, accurate and sensitive analytical techniques are required to control the level of these elements with good precision. The present manuscript will review different analytical tools used to analyze these samples. Because of their high sensitivity, low limits of detection, wide dynamic range, and in some cases the capability of carrying out multi-elemental analyses, the review is mainly focused on inductively coupled plasma techniques. Furthermore, sample preparation procedures (e.g., direct dilution, emulsification, extraction, and matrix decomposition) are elaborated. At the end of the work, suggestions on procedures for multi-elemental determination in the aforementioned samples are provided.
... Classical extraction is one of the basic techniques used to isolate phytochemicals from plant material. In recent years, great importance has been attached to the search of extraction methods that will be efficient and at the same time environmentally friendly (e.g., by limiting the reducing the amounts of solvent used) [7]. However, some factors, such as the characteristic astringent and bitter taste or low bioavailability of the isolated compounds often limit their use in many fields. ...
Article
Full-text available
Every year, the juice industry generates millions of tons of by-products worldwide such as seeds, skins and pomace. This creates significant environmental problems. It is estimated that about 25% of the fruit weight used in juice production is waste. However, even after processing, this waste contains high amounts of valuable bioactive substances. Phenolic compounds and pectin have been found to be the main components of apple pomace and are responsible for its antioxidant, anti-inflammatory, antibacterial, antifungal, and anticancer properties. However, the low bioavailability and sensitivity of some chemicals limit their use in many areas. Advanced extraction techniques and encapsulation of apple pomace extracts is a promising technique to overcome these problems and increasing their applicability (e.g., in the cosmetic, pharmaceutical, or food industries).
... AS flavonoids identified to date include hyperoside, quercetin, citrin, and rutin [8]. Conventional solvent extraction, using chemicals such as methanol, ethanol [9], and ethyl acetate, was previously used. However, organic solvents are expensive, flammable, toxic, and non-degradable, and their excessive use not only damages the natural environment, but also threatens human health [10]. ...
Article
Full-text available
In recent years, green extraction of bioactive compounds from herbal medicines has generated widespread interest. Deep eutectic solvents (DES) have widely replaced traditional organic solvents in the extraction process. In this study, the efficiencies of eight DESs in extracting flavonoids from Acanthopanax senticosus (AS) were compared. Response surface methodology (RSM) was employed to optimize the independent variable including ultrasonic power, water content, solid-liquid ratio, extraction temperature, and extraction time. DES composed of glycerol and levulinic acid (1:1) was chosen as the most suitable extraction medium. Optimal conditions were ultrasonic power of 500 W, water content of 28%, solid-liquid ratio of 1:18 g·mL−1, extraction temperature of 55 °C, and extraction time of 73 min. The extraction yield of total flavonoids reached 23.928 ± 0.071 mg·g−1, which was 40.7% higher compared with ultrasonic-assisted ethanol extraction. Macroporous resin (D-101, HPD-600, S-8 and AB-8) was used to recover flavonoids from extracts. The AB-8 resin showed higher adsorption/desorption performance, with a recovery rate of total flavonoids of up to 71.56 ± 0.256%. In addition, DES solvent could efficiently be reused twice. In summary, ultrasonic-assisted DES combined with the macroporous resin enrichment method is exceptionally effective in recovering flavonoids from AS, and provides a promising environmentally friendly and recyclable strategy for flavonoid extraction from natural plant sources.
... Organic solvents that do not meet the requirements of green chemistry, such as benzene, toluene, chloroform, dichloroethane, chlorobenzene, carbon tetrachloride, etc., will be used less frequently. They will be increasingly replaced by more environmentally friendly alternatives, including surfactants, ionic liquids, deep eutectic solvents, switchable solvents, supercritical fluids and biological solvents [133,134]. This could also help in the development of microextraction methods for sulfur species, for which none currently exist. ...
Article
This review discusses microextraction methods that have been published over the past twenty years for the determination of organic and inorganic sulfur species. The main advantages and disadvantages of the proposed microextraction methods for the determination of sulfur species are presented. The methods are compared in regard to several analytical parameters, such as sensitivity, selectivity and compliance with the requirements of green chemistry. The rate of occurrence of the selected types of microextraction methods and detection techniques is also discussed. Microextraction methods are often used to determine various organic sulfur species. These methods are primarily SPME and HS–SPME, which combine well with chromatographic techniques, especially GC–MS, GC–FID and HILIC–MS. Liquid microextraction methods, such as HS–SDME, DLLME and DI–SDME, are most often used to determine inorganic sulfur species and are combined with UV-Vis spectrophotometry, less often with HPLC or GC. Microextraction is an effective method for the determination of organic and inorganic sulfur species in real samples with a complex matrix. DLLME, HS–SDME and HS–SPME microextraction seem to us to be the most promising for the development of new methods for the determination of various sulfur species. Abbreviations: AED–atomic emission detector; CV–cyclic voltammetry; DAD–diode-array detector; DI–SDME–direct-immersion single-drop microextraction; DI–SPME–direct-immersion solid-phase microextraction; DLLME–dispersive liquid–liquid microextraction; ECD–electrochemical detection; ECLD–electrochemiluminescence detection; FAAS–flame atomic absorption spectrometry; FID–flame ionization detector; FPD–flame photometric detector; GC–gas chromatography; GDM–gas-diffusion microextraction; HF–LPME–hollow-fiber liquid-phase microextraction; HILIC–hydrophilic interaction chromatography; HLLME–FA–homogeneous liquid–liquid microextraction via flotation assistance; HPLC–high-performance liquid chromatography; HS–LPME–headspace liquid-phase microextraction; HS–SDME–headspace single-drop microextraction; HSSE–headspace sorptive extraction; HS–SPME–headspace solid-phase microextraction; HS–TFME–headspace thin-film microextraction; LC–liquid chromatography; LLE–liquid–liquid extraction; LOD–limit of detection; MS–mass spectrometry; PDMS–polydimethyl-siloxane; PFPD–pulsed flame photometric detector; QuEChERS–‘quick, easy, cheap, effective, rugged, and safe’, a solid-phase extraction technique; RSD–relative standard deviation; SALLME–salting-out-assisted liquid–liquid microextraction; SAs–sulfonamides; SCD–sulfur chemiluminescence detector; SERS–surface-enhanced Raman spectrometry; SNC–smartphone nanocolorimetry; SPE–solid-phase extraction; SPMMTE–solid-phase membrane micro-tip extraction; TD–turbidimetric detection; UHPLC–ultrahigh-performance liquid chromatography; USAE–ME–ultrasound-assisted emulsification microextraction; UV-Vis–ultraviolet–visible spectroscopy. Highlights Microextraction methods used to determine organic and inorganic sulfur species are described Microextraction combined with chromatographic, spectroscopic and electroanalytical detection techniques are reviewed Analytical characteristics and trends in the development of microextraction methods for the determination of sulfur species are discussed.
... One of the basic techniques used to isolate the active compounds from materials of plant origin is classical extraction. In recent years, considerable attention has been given to the development of extraction methods that will be both efficient and environmentally friendly, e.g., limiting the amounts of solvent used or favouring energy efficiency [6]. Raw AP or the solid extraction by-products can also be utilised as a feedstock for the production of various types of intermediate bioenergy carriers in liquid, solid or gaseous forms, i.e., bioethanol, biodiesel, biomethane [7], biogas [8], biochar [9] or raw material for batteries [10]. ...
Article
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In many countries, apple pomace (AP) is one of the most produced types of agri-food waste (globally, it is produced at a rate of ~4 million tons/year). If not managed properly, such bio-organic waste can cause serious pollution of the natural environment and public health hazards, mainly due to the risk of microbial contamination. This review shows that AP can be successfully reused in different industrial sectors—for example, as a source of energy and bio-materials—according to the idea of sustainable development. The recovered active compounds from AP can be applied as preservatives, antioxidants, anti-corrosion agents, wood protectors or biopolymers. Raw or processed forms of AP can also be considered as feedstocks for various bioenergy applications such as the production of intermediate bioenergy carriers (e.g., biogas and pyrolysis oil), and materials (e.g., biochar and activated carbon). In the future, AP and its active ingredients can be of great use due to their non-toxicity, biodegradability and biocompatibility. Given the increasing mass of produced AP, the commercial applications of AP could have a huge economic impact in the future.
... Molecules 2021,26, 2746 ...
Article
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The purpose of the current study was to determine the phenolic composition, antioxidant, and antimicrobial activities in grape cane extracts from typical cultivars of Southern Italy. Aqueous extracts at different pHs (1–13) were prepared from “Aglianico”, “Fiano”, and “Greco” grape canes. The results demonstrated that an alkaline pH (13.00) produced the best polyphenol-rich extracts, as the total phenolic content was more than double when compared to the respective extracts prepared at pH 1.00. “Greco” grape canes gave the highest quantity of phenolic compounds at each pH, ranging from 42.7 ± 0.4 to 104.3 ± 3.0 mg Gallic Acid Equivalents (GAE)/g Dry Extract (DE) from pH 1.00 to 13.00. The Radical Scavenging Activity (RSA) and the Ferric Reducing Antioxidant Power (FRAP) were measured. The highest antioxidant activity was showed by “Greco” extract at pH 7.00. Seventy-five compounds were identified in the extracts by HPLC-MS with six of them described for the first time in grape canes. Procyanidins were highly abundant in extracts at pH 7.00, whereas stilbenoids were the most represented compounds at pH 13.00. Very strong antiviral activity against herpes simplex viruses was recorded for the extracts at pH 7.00 and 13.00 that were active in the early stages of infection by acting directly against the viral particles. The overall results suggest that grape canes, currently underutilized, can be usefully valorised by providing active extracts to use as antioxidant and antiviral agents.
... Although DESs boast of having high greenness and low toxicity, some individual components used to prepare them may be toxic. For this reason, the term natural DES (NADES) has been usually employed to distinguish those non-harmful DES [16,17]. However, NADES definition is an inaccurate term since it may not include all non-toxic DES. ...
Article
In this work, a low toxicity deep eutectic solvent-based ferrofluid is presented for the first time as magnetic fluid to be used as an efficient solvent in liquid-based microextraction techniques. This ferrofluid is made of a hydrophobic deep eutectic solvent, composed by menthol and thymol in a 1:5 molar ratio as carrier solvent, and oleic acid-coated cobalt ferrite (CoFe2O4@oleic acid) magnetic nanoparticles. This material was characterized via magnetism measurement, scanning electron microscopy, infrared spectroscopy and density measurement. The determination of UV filters in environmental water samples was selected as model analytical application to test the extraction performance of this new ferrofluid by employing stir bar dispersive liquid microextraction, prior to liquid chromatography-tandem mass spectrometry analysis. The response surface methodology was used as a multivariate optimization method for extraction step. Under the optimized conditions, good analytical features were obtained, such as low limits of detection between 7 and 83 ng L⁻¹, good repeatability (relative standard deviations, RSD (%) below 15%), enrichment factors between 46-101 and relative recoveries between 80 and 117%, proving the good extraction capability of this ferrofluid. Finally, the method was successfully applied to three environmental waters (beach and river waters), finding trace amounts of the target UV filters. The presented low toxicity deep eutectic solvent-based ferrofluid results to be a good alternative to conventional solvents used in liquid-phase microextraction techniques.
... The high solubilizing ability, which enables the dissolution of a wide range of organic compounds, is also an important feature that distinguishes green solvents, especially when considering extraction processes. [26,27]. For this reason, it is crucial to develop strategies for selecting solvents that meet efficiency, safety, environmental hazard, and human health protection requirements. ...
Article
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New protocol for screening efficient and environmentally friendly solvents was proposed and experimentally verified. The guidance for solvent selection comes from computed solubility via COSMO-RS approach. Furthermore, solute-solvent affinities computed using advanced quantum chemistry level were used as a rationale for observed solvents ranking. The screening protocol pointed out that 4-formylomorpholine (4FM) is an attractive solubilizer compared to commonly used aprotic solvents such as DMSO and DMF. This was tested experimentally by measuring the solubility of the title compounds in aqueous binary mixtures in the temperature range between 298.15 K and 313.15 K. Additional measurements were also performed for aqueous binary mixtures of DMSO and DMF. It has been found that the solubility of studied aromatic amides is very high and quite similar in all three aprotic solvents. For most aqueous binary mixtures, a significant decrease in solubility with a decrease in the organic fraction is observed, indicating that all systems can be regarded as efficient solvent-anti-solvent pairs. In the case of salicylamide dissolved in aqueous-4FM binary mixtures, a strong synergistic effect has been found leading to the highest solubility for 0.6 mole fraction of 4-FM.
... Corrosion research in recent years has centered on creating low-cost, ecologically friendly chemicals [12]. Because of their environmental sustainability, low toxicity, and low cost, plant extracts are considered promising solutions to the problem of metal corrosion in many media, particularly acidic ones [13][14][15][16]. ...
Article
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The inhibitory potency of Citrullus colocynthis ethanolic seed extract (COCO) against corrosion of C38 steel in a hydrochloride media was studied by impedance spectroscopy (EIS) and potentiodynamic polarization (PDP). The polarization data demonstrated a mixed inhibitory behavior. Both polarization and EIS showed excellent agreement in inhibitory efficiency, with IE percent values of 94.9 and 95.8% at 2 g/L COCO extract. The adsorption follows the Langmuir model based on the isothermal analysis. The impact of time was also tested to ensure the inhibitor's stability for 72 h, and the study showed that COCO extract had sufficient stability to be used as an inhibitor. A GC–MS study of the extract and an SEM/EDX investigation of the metal surface were done to further understand this impact. The results of the GC–MS test revealed the existence of various chemicals that might be responsible for the inhibitor's corrosion-inhibiting properties. The presence of a protective barrier formed on the surface by adsorption of active COCO molecules has been established by SEM/EDX measurements.
... The viscosity of the NADES can be easily adjusted by increasing the water content maintaining the solvent properties (Dai et al., 2013a(Dai et al., , 2015. These green solvents have been used during the past decade in diverse applications such as: i) media for enzymatic or chemical reactions to solubilize or isolate macromolecules (Ma et al., 2020), ii) alternative for non-water-soluble drugs (Liu et al., 2018), iii) to develop cosmetic ingredients (Paiva et al., 2014), iv) for extraction of bioactive metabolites from plants (Dai et al., 2013b;Gonzalez et al., 2018), and v) biomedical applications (Plotka-Wasylka et al., 2017;Vanda et al., 2018). Nevertheless, there is still much to learn about the possible applications of the NADES. ...
Article
Natural Deep Eutectic Solvents (NADES) are composed of supramolecular interactions of two or more natural compounds, such as organic acids, sugars, and amino acids, and they are being used as a new media alternative to conventional solvents. In this study, a new application of NADES is presented as a possible technology for biofilm structural breaker in complex systems since the current solvents used for biofilm cleaning and extraction of biofilm components use hazardous solutions. The NADES (betaine:urea:water and Lactic acid:glucose:water) were analyzed before and after the biofilm treatment by attenuated total reflection Fourier-transform infrared spectroscopy and fluorescence excitation-emission matrix spectroscopy. Our results indicate that the green solvents could solubilize up to ≈70 percent of the main components of the biofilms extracellular matrix. The solubilization of the biomolecules weakened the biofilm structure, which could enhance the biofilm solubilization and removal. The NADES have the potential to be an environment-friendly, green solvent to extract valuable compounds and break the main structure from the biofilm, leading to a greener method for extracellular polymeric substance (EPS) extraction and biofilm treatment in various water treatment systems.
... To evaluate the effects of the hydrothermal process followed by freeze-drying, regarding the presence and maintenance of bioactive compounds, the application of aqueous extraction follows the premise of replacing solvents harmful to health and the environment with solvents inert to them, acting in line with the principles of green chemistry (Płotka-Wasylka et al., 2017;Pacheco-Fernández & Pino, 2019). ...
... As a result, the solute quickly diffuses from the solid phase into the solvent. [31][32][33] The anti-gout activity of A. paniculata leaf extract using the UAE method has not been reported. In this study, the UAE method will be used to make this extract with variations in time and amplitude conditions to get the best conditions so that the total phenolic content and the highest anti-uric acid activity results are obtained. ...
... Flavonoid extraction based on Green Analytical Chemistry intends to look for alternative and non-toxic solvents, increased energy efficiency and greater extraction yield, as well as reduced operation time, at a lower cost and aiming to mitigate the environmental impacts. Normally, the extraction step corresponds to 40% to 80% of the total cost of chemical processes [26][27][28]. Different extraction methods have been studied [27], in which solid-liquid extraction methods based on homogenizer-assisted (HAE), ultrasound-assisted (UAE) and microwave-assisted (MAE) extractions are used as sustainable methods to extract bioactive compounds from different types of plant material due to the possibility of using smaller volumes of greener solvents, lower sample mass and safety regarding the analyst [27,[29][30][31]. The analysis step, among other strategies, can benefit from miniaturization of analytical systems to reduce [10]); glu, glucose its environmental impact. ...
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Brazilian biodiversity and favourable environmental conditions open up possibilities not yet explored, showing potential to shift the country’s monochromatic economy into an emancipated, diversified and sustainable economic environment. This can be made possible through the integral use of its resources, exploring every functional fraction to create novel solutions to modern problems. Biorefineries present an interesting strategy to fully use the potential of agricultural feedstocks and together with green separation methods can contribute to the generation of sustainable processes and products. Passion Fruit (Passiflora edulis Sims f. flavicarpa Deg species) is produced on a large scale in Brazil and in other tropical countries, and its processing plants generate tons of residues that basically consist of peel, seeds and bagasse, which account for around 75% of its mass. These fractions of P. edulis can contain significant amounts of flavonoids, secondary metabolites that are the main compounds responsible for the fruit’s bioactivity (antioxidant, anti-inflammatory, pesticide and biocide, in general). Therefore, this work aims to develop, apply and compare the best conditions for the extraction of isoorientin, orientin and isovitexin from passion fruit applying solid–liquid methodologies, followed by analyte quantification using UHPLC-PDA. Homogenizer-assisted (HAE), ultrasound-assisted (UAE) and microwave-assisted (MAE) extraction techniques were used, as well as a full factorial design to reach optimal parameters concerning the extraction yield and energy and solvent efficiencies. According to the results, the procedure based on HAE presented the best conditions for the extraction of selected flavonoids (1.07, 0.90 and 0.33 mg g−1 of isoorientin, orientin and isovitexin, respectively) and was considered the best method according to the green and sustainable described factors.
... Therefore, there is a trend to replace it with the green extraction method. Sometimes solvent extraction has advantages such as low energy input (evaporation and distillation), the solvent can be recycled, and has selectivity [16][17][18]. On the other hand, CPE is an alternative green method for solvent extraction. ...
Article
This study reports a comparison between two types of extraction. The first one is traditional extraction which can be called liquid-liquid extraction (LLE) or solvent extraction, while the second is modern extraction, namely cloud point extraction (CPE). 3-Chloro-2,4-pentanedione was used as a complexing agent that is one of β-diketone that have an interesting in extracting copper ions. The current study showed that cloud point extraction (E%=92, D=11.594, LogD= 1.064233296) is more efficient than its counterpart (E%=80, D=4.089, LogD= 0.611). The cloud point extraction was studied using Triton X-100 as a non-ionic surfactant and ethyl acetate as a solvent. Also, complex CuA-Cl was prepared and characterized by elemental analysis and mass and UV-visible spectrometries.
... In recent years, deep eutectic solvents (DESs) have emerged as green alternatives to classical extractants in LPME with crucial advantages [11,12]. DESs are biodegradable, less toxic than classical solvents, and easy to synthesize from commercially available and economic precursors being typically one hydrogen bond donor (HBD) and one hydrogen bond acceptor (HBA) [13]. What is more, DESs are, similarly to ionic liquids, "tailored solvents", i.e., their physicochemical properties can be tuned by changing type and ratios of their components to modify viscosity and water solubility or to expand the range of analyte interactions beyond simple hydrophobic interaction to extract also polar or even ionic target compounds [14]. ...
Article
Lab-In-Syringe direct immersion single drop microextraction is proposed as an automated sample pretreatment methodology and coupled online to HPLC with fluorescence detection for the determination of fluoroquinolones in environmental waters. For the first time, a drop of a natural deep eutectic solvent (NADES), synthesized from hexanoic acid and thymol, has been used as an extractant in automated single-drop microextraction. The extraction procedure was carried out within the 5 mL void of an automatic syringe pump. A 9-position head valve served the aspiration of all required solutions, air, waste disposal, and hyphenation with the HPLC instrument. Sample mixing during extraction was done by a magnetic stirring bar placed inside the syringe. Only 60 μL of NADES were required omitting toxic classical solvents and improving the greenness of the proposed methodology. By direct injection, linear working ranges between 0.1 and 5 μg L⁻¹ were achieved for all fluoroquinolones. The limit of quantification values and enrichment factors ranged from 20 ng L⁻¹ to 30 ng L⁻¹ and 35 to 45, respectively. Accuracies obtained from the analysis of spiked surface water and wastewater treatment plant effluent analysis at two concentration levels (0.5 and 4 μg L⁻¹) ranged from 84.6% to 119.7%, with RSD values typically <3%.
Article
A simple supramolecular dispersive liquid-liquid microextraction-solidified floating organic drop (SMDLLME-SFOD) method was developed for the separation and preconcentration of brilliant green (BG) before its spectrophotometric determination. The method is based on the extraction of ion-pair of BG with sodium dodecyl sulfate into the coacervates made up of decanoic acid reverse micelles in the tetrahydrofuran-water mixture. The influence of the effective parameters on the extraction of BG was investigated and optimized using response surface methodology. Under the optimized conditions, the calibration graph was linear in the range of 1.0–50.0 μg L⁻¹ of BG. The limit of detection (LOD) and limit of quantification (LOQ) were 0.28 μg L⁻¹ and 0.94 μg L⁻¹, respectively. The repeatability expressed as the relative standard deviation for six replicate measurements at 5.0 μg L⁻¹ BG was 3.6%. The method was successfully applied to the extraction and determination of BG in different water and fish samples.
Article
Because of the increasing demand of greener solvents, deep eutectic solvents (DES) have just emerged as low-cost alternative solvents for a broad range of applications. However, recent toxicity assay studies showed a non-negligible toxic behavior for these solvents and their components. Alternative in silico-based approaches such as the one proposed here, multitasking-Quantitative Structure Toxicity Relationships (mtk-QSTR), are increasingly used for risk assessment of chemicals to speed up policy decisions. This work reports a mtk-QSTR modeling of 572 DES and their components under multiple experimental conditions. To set up a reliable model from such data, we examined here the use of 0D−2D descriptors along with classification analysis, and the Box−Jenkins approach. This procedure led to a final mtk-QSTR model with high overall accuracy and predictivity (ca. 90%). The model highlights also the crucial role that polarizability, electronegativity, hydrogen-bond donor (HBD), and topological properties play into the DES toxicity. Furthermore, with the help of the derived mtk-QSTR model, 30 different HBD components were ranked on the basis of their toxic contributions to DES. More importantly, the proposed in silico modeling approach is shown to be a valuable tool to mine relevant STR information, therefore guiding the rational design of potentially safe DES.
Chapter
Food waste is a precious source of organic carbon which can be utilized for the extraction and synthesis of several high value chemicals and represents a huge opportunity for eco-friendly green processes. The conversion of food waste to value added products is a hot research field. Technological hindrance is obviously due to the heterogeneous nature of the waste and its high moisture content. Anyhow, fine-tuning of the available strategies can pave the way to proper and economically viable management of FW. This Chapter deals with the technologies needed in a food waste-based biorefinery to put into practice the bioeconomy model, thereby realizing the sequential, circular, and sustainable use of the biomass that embodies the biocascading concept.
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Supercritical water (SCW) technology can be applied as an efficient and environment-friendly method to recover toxic or complex chemical wastes. Separation and chemical reactions under supercritical conditions may be realized by changing the temperature, pressure, and other operating parameters to adjust the physical and chemical properties of water. However, salt deposition and corrosion are often encountered during the treatment of inorganic substances, which will hinder the commercial applications of SCW technology. The solubility of salt in high pressure/temperature water forms the theoretical basis for studying the recovery of metal salts in supercritical water and understanding salt deposition. Therefore, this work systematically and objectively reviews different research methods used to analyze salt solubility in high pressure/temperature water, including the experimental method, prediction theoretical modeling, and computer simulation method; the research status and existing data of this parameter are also analyzed. The purpose of this review is to provide ideas and references for follow-up research by providing a comprehensive overview of salt solubility research methods and the current situation. Suggestions for more efficient metal recovery through technology integration are also provided.
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The epimers of catechin include epicatechin, epigallocatechin and epigallocatechin gallate, and others. They are important bioactives that have salutary effects, and hence are valuable. For ascertaining biologically-safe and green extraction methods that are non-thermal, this review evaluates the efficiencies of ultrasound assisted extraction (UAE) and supercritical (SC) fluid extraction (with CO2). Standalone SC-CO2 could be preferred over UAE, given its selectivity (purer product, no co-extracts) and absence of downstream processing. GRAS solvents as water and ethanol or a hydro-alcoholic mix are preferable for UAE. However, considering the core competency of ultrasound in disrupting cell organelles, a tandem approach with sequential SC extraction is recommended to justify process economics and ensure quality yield of catechin using green technologies.
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This work aims to remove the oil from passion fruit seeds using ethanol as solvent and then to carry out the transesterification of the product from the extraction step (oil + ethanol). The effects of operational variables in the ultrasound-assisted extraction (UAE) were evaluated and traditional extraction was performed for comparison. The extraction product was directed to the reaction step using an enzymatic catalyst. UAE provided oil yield from 12.32 to 21.76%, and the maximum value (73.7% of the traditional extraction yield) was obtained at 60 °C and 50 min using a solvent-to-seed ratio of 4. Oil removal was favored by increases in the investigated variables. g-tocopherol, δ-tocopherol and a high concentration of polyunsaturated fatty acids were identified in the oils. The oil obtained by UAE presented higher phytosterol contents. From the reaction step, samples were obtained with higher concentrations of ethyl esters, in addition to emulsifiers (diglycerides and monoglycerides).
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In recent years, the search for the principles of green chemistry in analytical methods has grown considerably. In green analytical chemistry, solvents occupy an essential place. Some criteria are necessary for a solvent to be qualified as a green medium, such as availability, low toxicity, biodegradability, and low cost. So far, the number of green solvents available is quite limited. Many extraction techniques have emerged as alternatives to conventional extraction procedures, using green solvents. A new group of solvents known as deep eutectic solvents (DESs) has emerged as a new and promising alternative for substituting traditional solvents. DESs attract attention due to their peculiar characteristics: eco-friendly, inexpensive, and simple to obtain. This work presents a critical review involving DESs in liquid-phase microextraction (LPME) and their contributions to green chemistry.
Chapter
The term “switchable solvents” (SS) is coined for solvents that can reversibly alter their physical properties to a great extent. The exceptional behavior of switchable solvents is governed by their reversible reaction in response to external incitement like temperature variation and/or the removal or addition of a gas. As a consequence of the switching ability of the chemical reaction, the solvent can be effortlessly changed back to its actual original form. For example, waste carbon dioxide gas, at 1 atm of pressure, is a mostly cheap and ecofriendly trigger as it is not only nontoxic and nonflammable, but it also can be easily removed. The probability of reversibility “switching” the physical properties and/or polarity of solvents like ionic or covalent liquid or gas can be controlled by manipulating its molecular level, which opens the foremost pathways for subsequent basic research and forthcoming chemical process development. The current article illustrates the types, properties, and exploitation of switchable solvents in various industrial applications as an alternate for green chemistry.
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Sample preparation is a challenge for high-throughput analysis, especially for volume-limited samples with low-abundant analytes. Ideally, sample preparation enriches the analytes of interest while removing the interferents to reduce the matrix effect and improve both sensitivity and quantification. In this study, a three-phase electroextraction (EE) method hyphenated to fast online liquid chromatography–mass spectrometry (LC-MS) was developed. Four model acidic drugs of relevance for drug monitoring in plasma, i.e. naproxen, fenoprofen, flurbiprofen, and ibuprofen, were utilized for the optimization and evaluation of the method. A Design of Experiment approach (Box-Behnken design) was used to optimize the critical parameters of the method, i.e., the type of organic solvent, pH of the sample and acceptor phase, and the extraction voltage and time. Good fitness (P < 0.02, R² > 0.95) was observed for the developed quadratic model. Extraction could be achieved in less than 2 min (115 s) with enrichment factors (EF) up to 190 and extraction recoveries (ER) up to 38% for academic samples. Additionally, the optimized three-phase EE method was successfully applied to spiked plasma samples with low-abundant (50 ng mL⁻¹) analytes and a low sample volume of 15 μL plasma in 10-fold diluted samples. Finally, two crucial contributors to the matrix effect of three-phase EE application on plasma samples were determined. Specifically, the ion-suppression effect in the MS source was reduced by the fast LC separation, and the matrix effect during extraction was negligible for the diluted protein-precipitated plasma samples. The developed three-phase EE method is easy to operate and provides fast and online extraction of trace-level acidic analytes from volume-limited biological samples. Therefore, this method can provide a potential solution for sample-preparation bottlenecks in high-throughput bioanalysis workflows.
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The limitations of atomic spectrometry (AS) for analyte quantitation and identification at trace and ultra-trace levels in complex matrices necessitate pre-processing. Extraction and digestion, both of which usually necessitate a large quantity of volatile and toxic solvents, are two of the most major pre-processing methods. Deep eutectic solvents (DESs), are environmentally friendly and exhibit extraordinary properties that researchers use to improve extraction and digestion efficiencies. Based on recent DES research, this review emphasizes applications of DESs in two representative pre-processing operations of AS analysis: liquid-phase microextraction (LPME) and solid sample digestion. Furthermore, several limitations and prospects on DESs in pre-processing for AS analysis are discussed.
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Bioactive compounds (BCs) extracted from plants have been under study since ancient times due to their outstanding features such as antioxidant, anticancer, anti-inflammatory, and antimicrobial properties. This has led to the development of various extraction techniques, which are classified as conventional (e.g., Soxhlet extraction, maceration, and hydrodistillation) and non-conventional (e.g., ultrasound-assisted extraction, ohmic extraction, supercritical fluid extraction), both seeking high yields and recovery effectiveness. However, these compounds have an important disadvantage, as they are very susceptible to degradation when exposed to heat, light, and humidity, among other factors. Micro and nanoencapsulation can protect the BCs from these factors allowing their controlled release, favoring their application in this manner. To build these systems several techniques and materials are used, and they must be properly selected as they directly influence their functionality and structural characteristics. Recently, micro and nanostructures have also been explored as carriers for BCs with the aim of combating microbial attacks on crops and extending the food products shelf life. This review covers relevant and updated information on BCs from plants, describing and discussing different extraction techniques and encapsulation processes. It also presents an updated summary about the most frequently used wall materials for encapsulating BCs. There is a review of the advantages that micro and nano encapsulation of BCs from plants can provide, showing that their design can improve their properties, which represents an excellent alternative to potentiate future applications that cover needs in several areas, mainly in the agri-food industry.
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In the current study, vortex assisted-liquid-liquid microextraction (VA-LLME) pretreatment method was developed based on superparamagnetic nanofluid and deep eutectic solvents for the isolation and preconcentration of quinolones in milk sample. The deep eutectic solvent-ferrofluid (DES-FF) with high extraction ability was prepared by combining DL-menthol/octanoic acid deep eutectic solvent and magnetic nanoparticles, which was mainly related to the strong interactions between extractant and analytes, such as hydrophobic interactions, hydrogen bonding attractions and electrostatic interactions. The functional group, and magnetic characteristics of the synthesized materials were characterized by using Fourier transform-infrared spectroscopy, X-ray diffraction, and vibrating sample magnetometer. The use of vortex instead of dispersed solvent in LLME is simple and quick, reducing the consumption of solvent and shortening the extraction time. The parameters which affected the extraction efficiency were investigated and optimized using response surface methodology (RSM). Under the optimum conditions, linearity (r>0.996) was in the range of 1.00-100 μg mL⁻¹. Limit of detection (LOD) and quantification (LOQ) of two quinolones varied in 0.30-0.35 μg mL⁻¹ and 0.80-1.0 μg mL⁻¹, respectively. The recoveries were in the range of 84.4-95.4%, RSD of intra-day and inter-day precision were not higher than 5.0% and 7.7%, respectively. Finally, the developed method was successfully applied for the determination of quinolones in milk.
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In this study, we reveal an Eu(III) extraction mechanism at the interface between HNO3 and tributyl phosphate (TBP) solutions using fluorescence microspectroscopy. The mass transfer rate constant at the interface is obtained from the analysis of fluorescence intensity changes during the forward and backward extractions at various HNO3 and TBP concentrations to investigate the reaction mechanism. This result indicates that one nitrate ion reacts with Eu(III) at the interface, whereas TBP molecules are not involved in the interfacial reaction, which is different from the results obtained using the NaNO3 solution in our previous study. We demonstrate that the chemical species of Eu(III) complex with nitrate ion and TBP in the aqueous solution play an important role for the extraction mechanism. The rate constants of the interfacial reactions in the forward and backward extractions are (4.0-5.0) × 10-7 m M-1 s-1 and (3.2-3.3) × 10-6 m s-1, respectively. We expect that our revealed mechanism provides useful and fundamental knowledge for actual solvent extraction.
Chapter
One of the lignocellulosic wastes that has obtained much interest in Malaysia is oil palm empty fruit bunch (EFB). EFB is sustainable and renewable as it is generated from the crude palm oil process as a by-product. As the whole fruit bunch undergoes the steaming process in the palm oil mill, EFB is normally in a wet condition with very high moisture content. If it is not processed immediately, EFB is prone to degradation, which affects the quality of the fiber. Basically, EFB consists of cellulose, hemicellulose, and lignin. EFB fibers are partially separated by shredding the bunches. Some of the palm oil mills double shred the bunch and send it out to their plantations as mulching material. However, many of the mills just pile it at the plantation, letting it degrade slowly to create organic stockpile for the soil. Despite utilizing EFB for this low-end usage, EFB fiber has the potential to produce higher end products and has been recognized as an important lignocellulosic biomass. Due to its abundant availability in Malaysia, it is potentially considered as the main candidate as a substitute for wood and to assist in dealing with wood shortage problems.
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Analytical research with adverse environmental impact has caused a severe rise in concern about the ecological consequences of its strategies, most notably the use and emission of harmful solvents/ reagents into the atmosphere. Nowadays, industries are searching for the best reproducible methods. Voriconazole is a second-generation azole derivative used effectively in the treatment of Candida and Aspergillus species infections and oropharyngeal candidiasis in AIDS patients. Recently it has become the drug of choice in treating mucormycosis in several countries, which raises the need for production in large quantities. The present review deals with various recent important analytical techniques used to estimate voriconazole and its combination in pharmaceutical formulations and biological fluids. The methods show their own unique way of analyzing voriconazole in different matrices with excellent linearity, detection, and quantification limits. Additionally, this article deals with methods and solvents analyzed for their impact on the environment. This is followed by estimating the degree of greenness of the methods using various available assessment tools like analytical eco-scale, national environmental method index, green analytical procedure index, and AGREE metrics to confirm the environmental impact. The scores obtained with the evaluation tools depict the quantum of greenness for the reported methods and provide an ideal approach adopted for VOR estimation. Very few methods are eco-friendly, which shows that there is a need for the budding analyst to develop methods based on green analytical principles to protect the environment.
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The use of ionic liquids (ILs) in different fields of analytical chemistry has increased exponentially in recent years, leading to the development of new technologies that try to respect the guidelines proposed by Green Chemistry. ILs are considered ecological compounds due to their thermal stability and non-volatility at room temperature, which prevents their release into the atmosphere. However, recent studies have shown that the growing number of applications that involve them has led to pollution to the aquatic and terrestrial compartments. Despite this, ILs have become environmentally friendlier alternatives to conventional toxic organic solvents for their application in microextraction techniques, both as liquid phases or combined with nanomaterials for solid phase extraction. In addition to this, the use of ILs as mobile and stationary phase additives in chromatographic techniques has introduced substantial improvements in these separation techniques. Likewise, advanced electrodes have been obtained thanks to the functionalization of nanomaterials with ILs for more selective and sensitive electrochemical determinations. In this review, the use of ILs in the development of innovative and efficient analytical methods applied for food and beverage analysis is revised. Special emphasis is made on the environmental impact of the reviewed applications, including their analysis via the AGREE software, which allows the obtention of a numerical estimation of the greenness of an analytical method. In addition, critical issues and future challenges arising from the application of ILs in microextraction, chromatography and electrochemical techniques are discussed.
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The extraction of molecules with high added value plays an important role in the recovery of food waste. This work aimed to valorize tomato pomace, a by-product composed of skin and seeds, through extraction of carotenoids, especially lycopene and β-carotene. The tomato pomace was dried using three different methods (freeze-drying, heat drying, and non-thermal air-drying) to reduce its weight, volume, and water activity and to concentrate the carotenoid fraction. These drying approaches were compared considering the extractive potential. Three solvent mixtures were compared, a traditional one (n-hexane:acetone) and two green deep eutectic solvent mixtures (ethyl acetate:ethyl lactate and menthol:lactic acid) in combination with different drying procedures. The extract obtained using ethyl acetate:ethyl lactate with non-thermal air-drying showed the highest contents of lycopene and β-carotene (75.86 and 3950.08 µg/g of dried sample, respectively) compared with the other procedures.
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Agro-foodindustries generate colossal amounts of non-edible waste and by-products, easily accessible as raw materials for up-cycling active phytochemicals. Phenolic compounds are particularly relevant in this field given their abundance in plant residues and the market interest of their functionalities (e.g. natural antioxidant activity) as part of nutraceutical, cosmetological and biomedical formulations. In “bench-to-bedside” achievements, sample extraction is essential because valorization benefits from matrix desorption and solubilization of targeted phytocompounds. Specifically, the composition and polarity of the extractant, the optimal sample particle size and sample:solvent ratio, as well as pH, pressure and temperature are strategic for the release and stability of mobilized species. On the other hand, current green chemistry environmental rules require extraction approaches that eliminate polluting consumables and reduce energy needs. Thus, the following pages provide an update on advanced technologies for the sustainable and efficient recovery of phenolics from plant matrices.
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A novel green modified QuEChERS based on green deep eutectic solvents (DES) followed by GC-MS was developed to analyze pesticides in tea samples. Among different tested DESs for the extraction of analytes, ChCl:PEG (1:4) DES showed the highest efficiency. Three-dimensional magnetic graphene was functionalized by ChCl:urea (1:2) natural DES, characterized and used as sorbent in the in-syringe dispersive micro-SPE to cleanup tea extract. Under optimized conditions, linear range was 0.70-500 μg kg⁻¹. The limits of quantification (0.70-1.90 μg kg⁻¹) were lower than the maximum residue levels established by the European Union for pesticides in tea (0.015-0.1 mg kg⁻¹). The method was applied to detect pesticides in green and black teas, and the recoveries were 70.2-105.2%. This work represents the first application of ChCl:PEG DES and 3DGA-Fe3O4/ChCl:urea in extraction of pesticides and tea sample cleanup, respectively. The greenness of procedure was evaluated by Analytical Eco-Scale and Complementary Green Analytical Procedure Index.
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Coffee pulp (CP) is a waste from the industrial coffee production which cause a problem in management of environment including acidic soil quality and unpleasant odors. In this study, Arabica CP was value added as functional ingredient in cosmetic product. The CP was extracted with water and dried via freeze drying to obtained coffee pulp extract (CPE). The total phenolic content of CPE was determined to be 45.12 ± 1.08 mg GAE/g extract. The chlorogenic acid, a bioactive compound in CP was found to be 17.8 mg/kg. In the biological evaluation, it was found that CPE showed antioxidant activity in 3 assays of ABTS, DPPH and superoxide radicals-scavenging. The half maximal inhibitory concentration (IC 50) were 0.59, 0.94 and 9.53 mg/ml, respectively. Furthermore, CPE was shown inhibition of tyrosinase, this enzyme plays an important role in melanogenesis which IC 50 was 125.21 mg/ml. From the above experiments, CPE exhibits functional properties for anti-aging cosmetics. CPE was formulated in facial cream product and then the stability test was evaluated in various conditions such as 4°C, room temperature and 45°C for 90 days as well as accelerated stability test under 6 heat-cool cycle. The facial cream demonstrated good physical stability under 4 various conditions. Therefore, CPE has the potential to add the value as functional ingredient in cosmetic products.
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The high oil content of nuts and its fatty acid profile with biological proprieties positively affect blood lipids and lipoproteins. Nuts are low in saturated and high in unsaturated fatty acids (MUFA and PUFA) and are rich sources of other essential nutrients. Vegetable oils extraction is usually done through conventional methods like Soxhlet, cold-pressed Bligh, and Dyer methods. These methods are easy to perform, but they present several disadvantages, mainly related to environmental pollution and long extraction times. Therefore, emerging and green extraction technologies such as supercritical/subcritical, ultrasound, microwave, and enzyme-assisted extractions have been developed and were revised in this paper, showing relevant advantages over traditional methods. These technologies are environmentally friendly, allow the reduction of extraction time, the extraction yields are usually not very different from the obtained with conventional methods, and allow getting oils of better quality, which are less susceptible to oxidation processes.
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Task-specific ionic liquids (TSILs) represent a sub-family of ionic liquids characterized by their high specificity towards a target analyte or group of analytes. This characteristic has made them valuable tools for sample preparation, where selectivity represents a key aspect, especially when other species represent a significant source of interference or when non-specific detectors are used. This review presents an overview of TSILs applications for sample preparation from the last ten years, with a special emphasis on their use as liquid-liquid microextraction solvents or as functionalizing agents for sorbents applied to solid-phase microextractions. TSILs applications for the treatment of environmental, food and biological samples are reviewed, including reports devoted to speciation analysis, a relevant trend in recent years regarding elemental studies. Additionally, focus will be made on the ‘task-specificity’ of the presented TSILs, including a description of the chemical characteristics that made them selective towards the studied analytes. Finally, future trends and gaps to be covered in the field are also presented discussed.
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Liquid – liquid extraction (LLE) processes have been widely applied to extract active pharmaceutical compounds (APCs) from plant materials at both the laboratory and industrial-scale. The approach to modify the aqueous phase with small molecule organic modifiers has been used to increase the solubility of APCs in the aqueous phase. This work investigates the solvent loss for 18 LLE systems, including three aqueous phase modifiers (methanol, ethanol and acetone), three traditional volatile organic compounds (VOCs) solvents (xylene, methyl isobutyl ketone (MIBK) and n-heptane) and three green solvents (d-limonene, α-pinene and p-cymene) with the aim of identifying the most suitable solvents for cannabinoid extraction from cannabis tissues. The solvent selection screening using COnductor-like Screening MOdel - Segment Activity Coefficient (COSMO-SAC) modelling was investigated. The loss of modifier into organic solvents generally increases as the original modifier concentration in aqueous solution increases. Methanol and ethanol are preferred for use in pharmaceutical LLE processes with volume fractions in organic phases at equilibrium of ≤ 0.02 v/v and ≤ 0.06 v/v, respectively. The organic solvent loss into the alcoholic aqueous phase at ≤ 0.8 v/v alcohol/water aqueous phase is negligible. MIBK and acetone are not suitable for pharmaceutical LLE processes with the presence of the modifier. Both Hanson solubility parameters (HSPs) and COSMO-SAC modelling show good agreement with the experimental outcomes.
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The influence of ultrasound treatment (US) on cellular damage of olive leaf tissue was studied. Mechanical damage and thermal effect of US were characterized. The level of tissue damage was defined by the diffusivity disintegration index ZD based on the diffusivity of solutes extracted from olive leaves differently treated. The Arrhenius form using the temperature dependences of the thermal treatment time within the temperature interval 20-90°C was observed for the thermal process. The corresponding activation energy ΔUT was estimated as 57 kJ/mol. The temperature dependences of electrical conductivity were measured for extracts of intact and maximally treated olive leaves. Then the diffusivity disintegration index ZD and total phenolic compounds recovery for three studied US powers were calculated (100, 200, and 400 W). The results evidenced that the mechanically stimulated damage in olive leaf tissue can occur even at a low US power of 100 W if treatment time is long enough (t = 3.5 h). The US treatment noticeably accelerated the diffusion process mechanically in addition to its thermal effect. Trials in aqueous solution revealed the dependence of polyphenols extraction on damage level with respect to the US power applied.
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This review article points out, through an overview, aspects that are related to the procedures established by green analytical chemistry, for the extraction of bioactive compounds in plants, through the use of assisted techniques, as well as green solvents. Procedures that have less negative impact on the environment are being increasingly required for the extraction of biocompounds in the area of analytical chemistry due to aspects of sustainability, profitability and efficiency. To this end, green procedures aim to design environmentally benign chemical processes and synthetic methodologies, to eliminate or reduce the use of dangerous and toxic chemicals at any stage of production in industry or even in the laboratory. These extraction procedures will be defined as “green”, when using alternative solvents, reducing energy consumption, in addition to ensuring the safety and high quality of the extract. This review provides an overview of the green procedures applied and which had an effective action in the extraction of bioactive compounds in medicinal plants, supported thus by innovative, sustainable, and unconventional energy sources.
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Developing new, eco-friendly solvents which would meet technological and economic demands is perhaps the most popular aspects of Green Chemistry. Natural deep eutectic solvents (NADES) fully meet green chemistry principles. These solvents offer many advantages including biodegradability, low toxicity, sustainability, low costs and simple preparation. This paper provides an overview of knowledge regarding NADES with special emphasis on extraction applications and further perspectives as truly sustainable solvents.
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Green analytical chemistry although is not a new concept, it does not have greenness metrics system. Green chemistry metrics is not suitable for analytical procedures assessments because they often refer to the mass of product. Some efforts have been made to develop suitable metrics for analytical chemistry. Some are simple to use but do not cover all aspect of procedure environmental impact. Others are more comprehensive but may be difficult to be applied. The analytical reagents were not assessed but some clues about their greenness can be obtained from assessments from other branches of chemistry. New reagents and solvents applied in analytical chemistry require their detailed assessment in terms of greenness. Environmental issues have to be taken into consideration during reagents and solvents selection, analytical wastes disposal practices, analytical processes energetic requirements and development or selection of analytical procedures and for that reasons metrics systems are required.
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Previously it was demonstrated that natural deep eutectic solvents (NADES) are promising green solvents for the extraction of natural products. However, despite their potential, an obvious disadvantage of NADES is the high viscosity. Here we explored the dilution effect on the structures and physicochemical properties of NADES and their improvements of applications using quercetin and carthamin. The results of FT-IR and (1)H NMR experiments demonstrated that there are intensive H-bonding interactions between the two components of NADES and dilution with water caused the interactions weaken gradually and even disappeared completely at around 50% (v/v) water addition. A small amount of water could reduce the viscosity of NADES to the range of water and increase the conductivity by up to 100 times for some NADES. This study provides the basis for modulating NADES in a controllable way for their applications in food processing, enzyme reactions, pharmaceuticals and cosmetics. Copyright © 2015 Elsevier Ltd. All rights reserved.
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The improvement of sample-preparation and extraction techniques for determinations of natural bioactive compounds is very important. New concepts relate to not only enhancement of extraction efficiencies but also environmental impact. This evolution towards Green Analytical Chemistry is to new extraction and sample-preparation processes that should be faster, more reproducible and more environmentally friendly.Compressed fluid-based sample-preparation techniques (e.g., supercritical fluid extraction and pressurized liquid extraction) demonstrate good capabilities. In this review, we update knowledge on the techniques together with the main technical developments and the most notable recent applications for the extraction of bioactive compounds.
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A method is presented for hollow fiber liquid-phase microextraction (HF-LPME) of cadmium(II), which is chelated with 1-(2-pyridylazo)-2-naphthol (PAN) to obtain a hydrophobic complex which then is extracted into a polypropylene hollow fiber containing an ionic liquid in its pores which acts as the membrane phase. EDTA is then injected into the lumen of the membrane as an acceptor phase to trap the analyte. The extraction time (20 min), agitation (400 rpm at 25 °C), pH value (10.0), and the concentrations of PAN (2.5 ng mL−1) and EDTA (250 ng mL−1) were optimized. With a sample volume of 50 mL and a stripping volume of 15 μL, the enrichment factor is 162. Cadmium(II) was then quantified by graphite furnace AAS. The limit of detection is 0.12 pg mL−1, the relative standard deviation is 5.2 %, and the linear working range extends from 4 to 45 pg mL−1. The method was successfully applied to the determination of Cd(II) in environmental and food samples. Figure A method is presented for hollow fiber liquid-phase microextraction (HF-LPME) of cadmium(II), which is chelated with 1-(2-pyridylazo)-2-naphthol (PAN). Cadmium(II) was quantified by graphite furnace AAS. The limit of detection is 0.12 pg mL−1, the relative standard deviation is 5.2 %, and the linear working range extends from 4 to 45 pg mL−1.
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In this work, a fast and miniaturised procedure based on the use of a natural deep eutectic solvent (NADES) in combination with ultrasound-assisted extraction (UAE) has been proposed for gluten determination by a commercial enzyme-linked immunosorbent assay (ELISA). Fourteen NADESs were prepared by combining two natural primary metabolites and water. Studies on NADES viscosity and gluten solubilisation in NADESs and ethanol-water solutions (for comparison purposes) were carried out. Different strategies for speeding-up gluten solubilisation in NADESs were evaluated: dilution, temperature and sonication by a cup-horn sonoreactor. Diluted fructose-citric acid NADES and sonication were finally selected for gluten solubilisation. Solubilised proteins were characterized by electrophoresis and molecular fluorescence. The proposed procedure was also assessed in real samples, especially ultrasound time. Kit solvents (including reducing agents) were replaced by NADES, and hence, a reassessing of immunoassay system was necessary. Samples with and without gluten as well as recovery tests were used for this purpose. Recoveries were in the range of 79–106% and the repeatability, expressed as relative standard deviation, was better than 15%.
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A rapid, simple and green ultrasound-assisted extraction method using deep eutectic solvents (DES) for extraction of As, Cr, Mo, Sb, Se and V in soil samples, has been developed. Choline chloride–oxalic acid based DES was used as a solvent. The target analytes were subsequently quantified using inductively coupled plasma optical emission spectrometer (ICP OES). The parameters that affect the extraction of the target analytes was optimized using standard reference material of San Joaquin soil (SRM 2709a). In the optimization step, a two-level full factorial experimental design was used. The factors under investigation include extraction time, sample mass and acid concentration. Under optimized conditions, limits of detection (LOD) and limits of quantification (LOQ) ranged from 0.009 to 0.1 and 0.03–0.3 µg g⁻¹, respectively. The repeatability (n=20) estimated in terms of relative standard deviation (%RSD) ranged from 0.9% to 3.7%. The accuracy of the proposed method was carried out using SRM 2709a. The obtained and certified/ indicative values were statistically in good agreement at 95% confidence level. The proposed method applied for quantification of As, Cr, Mo, Sb, Se and V in real soil samples. For comparison, the analytes of interest were also determined using a conventional acid digestion method. According to the paired t-test, the analytical results were not significant differences at 95% confidence level. The method was found to be accurate, precise and environmentally friendly.
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A novel deep eutectic solvent based ultrasound-assisted liquid phase microextraction (DES-UALPME) has introduced for preconcentration of cobalt. Deep eutectic solvents (DESs) are studied as a green and eco-friendly solvents. In this method, 1-nitroso-2-naphthol was used as ligand. Cobalt concentration in DES rich phase was measured by a microsample injection system coupled with flame atomic absorption spectrometer (MS-FAAS). Under optimum conditions, LOD, LOQ, preconcentration factor (PF) and % RSD were determined as 1.10 μg L− 1, 3.60 μg L− 1, 20 and 7.1% respectively. The accuracy of the developed method was evaluated by the analysis of a pharmaceutical supplement and tea samples. Recoveries of certified reference materials and spiked samples were obtained in the range of 97–105%. Finally, the performance characteristics of the proposed method were compared with other liquid phase microextraction procedures.
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The monitoring of compounds present in samples at trace/ultra-trace level usually requires a preliminary step of isolation and/or enrichment of analytes. Against, sample preparation is considered as crucial part of whole analytical procedures, in particular in samples characterized by complex matrices composition. Several new miniaturized extraction techniques is introduced and extensively applied to different type of samples. Here you can highlight solid phase microextraction (SPME) and liquid phase microextraction (LPME). LPME was introduced to overcome drawbacks of liquid liquid extraction (LLE). Based on the recently published literature data, this review provides an update of the most important features and application of LPME. Comparison of these techniques have been made. Moreover, application of different type of LPME techniques for the extraction of different kind of materials such as biological, environmental, pharmaceutical and food was summarized.
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Superheated water extraction (SWE) has become an interesting green extraction method for different classes of compounds. In this study, SWE was used to extract glycyrrhizic acid (GA) from licorice root. Response surface methodology (RSM) was applied to evaluate and optimize the extraction conditions. The influence of operating conditions such as water temperature (100, 120 and 140 °C) and solvent flow rates (1, 3 and 5 mL/min) were investigated at 0.5 mm mean particle size and 20 bar pressure. Separation and identification of the glycyrrhizic acid, as the main component, was carried out by the RP-HPLC method. The best operating conditions for the SWE of licorice were determined to be 100°C temperature,15 mL/min flow rate and 120 min extraction time. The results showed that the amount of the obtained GA was relatively higher using SWE (54.760 mg/g) than the Soxhlet method (28.760 mg/g) and ultrasonic extraction (18.240 mg/g).
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Determination of methamphetamine in forensic laboratories is a major issue due to its health and social harm. In this work, a simple, sensitive, and environmental friendly method based on ionic liquid dispersive liquid-liquid microextraction combined with high-performance liquid chromatography was established for the analysis of methamphetamine in human urine. 1-Octyl-3-methylimidazolium hexafluorophosphate with the help of disperser solvent methanol was selected as the microextraction solvent in this process. Various parameters affecting the extraction efficiency of methamphetamine were investigated systemically, including extraction solvent and its volume, disperser solvent and its volume, sample pH, extraction temperature and centrifugal time. Under the optimized conditions, a good linearity was obtained in the concentration range of 10-1000 ng mL(-1) with determination coefficient larger than 0.99. The limit of detection calculated at a signal-to-noise ratio of 3 was 1.7 ng mL(-1) and the relative standard deviations for six replicate experiments at three different concentration levels of 100, 500 and 1000 ng mL(-1) were 6.4, 4.5 and 4.7%, respectively. Meanwhile, up to 220-fold enrichment factor of methamphetamine and acceptable extraction recovery (> 80.0%) could be achieved. Furthermore, this method has been successfully employed for the sensitive detection of a urine sample from a suspected drug abuser. This article is protected by copyright. All rights reserved.
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NAtural Deep Eutectic Solvents (NADES) are chemically simple but physiologically important plant constituents that exhibit unique solubilizing properties of other metabolites, including bioactive constituents. The high polarity of NADES introduces a challenge in the ability of conventional solid-support based chromatography to recover potential bioactive metabolites. This complicates the systematic explanation of the NADES' functions in botanical extracts. The present study utilizes countercurrent separation (CCS) methodology to overcome the recovery challenge. To demonstrate its feasibility, Glucose-Choline chloride-Water (GCWat, 2:5:5, mole/mol) served as a model NADES, and four widely used marker flavonoids with different polarities (rutin, quercetin, kaempferol, and daidzein) were chosen as model target analytes. In order to prepare GCWat with high consistency, a water drying study was performed. The unique capabilities of the recently introduced CherryOne system, offering volumetric phase metering, were used to monitor the CCS operations. The collected fractions were analyzed using UHPLC and NMR/quantitative NMR. CCS was able to recover the analytes from the NADES matrix with quantitative recovery efficiencies of 95.7%, 94.6%, 97.0%, and 96.7% for rutin, quercetin, kaempferol, and daidzein respectively. The CCS strategy enables recovery of target metabolites from NADES-containing crude extracts as well as from other chemical mixtures, and moreover offers a means of using NADES as environmentally friendly extraction solvents.
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Selected native Greek medicinal plants, including dittany, fennel, marjoram, mint and sage, were used to test the efficiency of some novel lactic acid-based natural deep eutectic solvents (NADES) to extract polyphenolic compounds. Extractions were performed under ultrasonication and the eutectic mixtures, tested as 80% (v/v) aqueous solutions, were lactic acid:choline chloride, lactic acid:sodium acetate, lactic acid:ammonium acetate and lactic acid:glycine:water, with corresponding molar ratios of 3:1, 3:1, 3:1 and 3:1:3. The three latter NADES are reported for the first time. Water and 60% (v/v) aqueous ethanol were also used as control solvents. The results obtained evidenced that lactic acid:glycine:water exhibited high efficiency, but in some instances lactic acid:sodium acetate and lactic acid:ammonium acetate were equally efficient. The data also suggested that extracts with high polyphenol concentration may also possess higher antiradical activity and reducing power. The NADES tested are non-toxic, renewable and exceptionally efficient solvents for polyphenol recovery from medicinal plants. The findings of this study were interpreted on the ground of assumptions regarding the polarity of the NADES tested.
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A novel method, termed ionic liquid-based hollow fibre liquid phase microextraction (IL-HF-PLME), coupled with high-performance liquid chromatography (HPLC) was developed for separation and preconcentration of three phthalate esters (PAEs) in tea beverage. In the present study, ionic liquid 1-butyl-3-methy-limidazolium hexafluorophosphate ([BMIm]PF6) was placed in the porous-walled polypropylene hollow fibre as the acceptor phase, and nonanol was used as the supported liquid membrane phase that accomplished extraction. Several important parameters influencing the extraction efficiency were investigated in detail. Under the optimized conditions, good linearity occurred in the range of 5-1000 ng mL−1 with the correlation coefficients values above 0.998. The limits of detection ranged from 0.67 to 1.73 ng mL−1. Recoveries of three PAEs in two kinds of spiked tea beverage samples (PAEs, 10.0 - 100.0 ng mL) were between 94.2 and 103.4%, with relative standard deviations (RSDs) ranged from 1.77 to 3.02%. The enrichment factors were 200. The developed IL-HF-PLME method allowed the simple, rapid, and sensitive determination of phthalate esters in tea beverage samples with an extraction time of just 4 min.
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The development of efficient and environmentally benign synthetic protocols has attracted increasing interest in modern organic syntheses in view of the growing concern over the environment. As part of this green concept, eutectic solvents (DESs) have emerged as an interesting type of ionic liquid and have shown their usefulness as environmentally benign sustainable alternative to the conventional organic solvents in synthetic chemistry to increase efficiency of organic transformations. The synthetic methodology with the use of DES as green solvent and inexpensive, biodegradable, recyclable catalyst and with its experimental simplicity and maximum synthetic efficiency will be attractive for academic and industrial research looking forward for simple catalytic organic transformations to synthesize drug like small molecules with structural diversity and molecular complexity. The present review focuses on the use of environmentally benign and inexpensive DES as solvent and catalyst in the field of organic chemistry.
Chapter
Global warming is a critical issue facing human beings due to greenhouse gas emissions, especially CO2 emissions. Mitigating CO2 emissions by Carbon capture and storage (CCS) has become a hot topic today. CO2 separation is a crucial step in CCS and is an energy-intensive process. Ionic liquids (ILs) as green solvents have gained tremendous attention for use as liquid absorbents for CO2 separation. However, the high price, toxicity, and poor biodegradability limit the application of ILs. Recently, deep eutectic solvents (DESs) based on choline chloride (ChCl) (i.e., choline-based DESs) were proposed as a new type of ILs but with additional advantages in cost, environmental impact, and synthesis. To promote the application of choline-based DESs in CO2 separation, the research work on the microstructure and physicochemical properties of choline-based DESs as well as the water effect were surveyed and compared with traditional ILs. The potential applications of choline-based DESs in CO2 separation and the challenges were further analyzed. It is shown that choline-based DESs are promising for use as liquid absorbents for CO2 separation, and the performance of ChCl/urea (1:2) is better than that for other choline-based DESs. However, uncertainties and bottlenecks still exist, and further study on the microstructure and properties needs to be carried out from experimental measurements to model developments.
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Replacement of volatile organic compounds (VOCs) by greener or more environmentally sustainable solvents is becoming increasingly important due to the increasing health and environmental concerns as well as economic pressures associated with VOCs. Solvents that are derived from biomass, namely bio-derived solvents, are a type of green solvent that have attracted intensive investigations in recent years because of their advantages over conventional VOCs, such as low toxicity, biodegradability and renewability. This review aims to summarize the use of bio-derived solvents in solvent extraction applications, with special emphasis given to utilization of biodiesels and terpenes. Compared with the conventional VOCs, the overall performance of these bio-derived solvents is comparable in terms of extraction yields and selectivity for natural product extraction and no difference was found for metal extraction. To date most researchers have focused on laboratory scale thermodynamics studies. Future work is required to develop and test new bio-derived solvents and understand the kinetic performance as well as solvent extraction pilot plant studies.
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The selection of suitable solvents is a crucially important subject in a wide range of chemical processes. This study presents a solvent selection guide where 151 solvents were assessed, including a significant number of recently reported bio-based solvents. The assessment procedure involves grouping of solvents according to their physicochemical parameters and ranking within clusters according to their toxicological and hazard parameters. Grouping of solvents resulted in the formation of three clusters – nonpolar and volatile (35 solvents), nonpolar and sparingly volatile (35 solvents) and polar ones (81 solvents). The comparison of toxicological and hazard related data indicated that solvents from the third cluster should be preferentially chosen. Within each group, a solvent ranking was performed by means of the TOPSIS procedure based on 15 different criteria. Because of the lack of certain data (especially toxicological), different ranking confidence levels were introduced. The highest confidence rankings were performed only for some solvents but with all the considered criteria. Low confidence rankings were created for all solvents but were based on certain criteria only. The results of our solvent selection guide (SSG) are generally in agreement with the results of others but allow for finer ranking of solvents. The assessment procedure is easy to adapt to individual chemists’ needs and allows including new solvents to the ranking.
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Green Chemistry plays a more and more important role in implementing rules of sustainable development to prevent environmental pollution caused by technological processes, while simultaneously increasing the production yield. Ionic liquids (ILs) and deep eutectic solvents (DESs) constitute a very broad group of substances. Apart from many imperfections, ILs and DESs have been the most promising discoveries in the world of Green Chemistry in recent years. The main advantage of ILs is their unique physicochemical properties-they are very desirable from the technological point of view, but apart from these benefits, ILs appear to be highly toxic towards organisms from different trophic levels. DES areas of usage are very spread, because they cover organic synthesis, extraction processes, electrochemistry, enzymatic reactions and many others. Moreover, DESs seem to be a less toxic alternative to ionic liquids. New possibilities of applications and future development trends are sought and presented, including such important solutions of life branches as pharmaceuticals' production and medicine.
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In this study, novel and green natural deep eutectic solvents (NADESs) as extraction media, are presented for the extraction and determination of phenolics in Cajanus cajan leaves by ultra performance liquid chromatography. Fourteen different NADES systems were investigated for the extraction of phenolics with diverse polarity in C. cajan leaves. Experiments with different extraction solvents and multivariate data analysis demonstrated that the NADES composed of choline chloride and maltose possessed excellent extractability for both polar and weak polar compounds compared to conventional solvents. The influential parameters of microwave-assisted extraction procedure with NADES were examined and optimized. The optimized conditions were as follows: extraction solvent 20% of water in choline chloride/maltose (1/2), extraction temperature 60 oC, liquid/solid ratio 30:1 mL/g and irradiation time 12 min. Moreover, a fast and sensitive UPLC method was firstly developed for the comprehensive analysis of fourteen phenolics in C. cajan leaves. This method was performed within 40 min, and exhibited satisfactory linearity, precision and recovery. These results indicate that the proposed method represents an excellent alternative for the extraction and quantification of phenolics in plant materials.