Development and Application of Green or Sustainable Strategies in Analytical Chemistry

A special issue of Separations (ISSN 2297-8739). This special issue belongs to the section "Materials in Separation Science".

Deadline for manuscript submissions: closed (10 December 2022) | Viewed by 28070

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Special Issue Editor

Department of Chemistry and Chemical Technologies, University of Calabria, Arcavacata, Italy
Interests: analytical chemistry; sample preparation; microextraction techniques; method optimization; environmental analytical chemistry
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Analytical chemistry is bound to face growing challenges in the near future, especially for the quantification of trace analytes in complex matrices. Although the development of increasingly sensitive and specific instrumental techniques has achieved remarkable results, sample preparation is still a fundamental step, often limiting the whole workflow.

In the context spawned by the recent international environmental policies that are responsive to the rapport of human activities with the surrounding environment, chemistry cannot hesitate to give its contribution. Almost pioneeringly, in analytical chemistry, we have been talking for some time about “green analytical chemistry”, its guiding principles, and the development of eco-friendly analytical approaches. However, the new and still open challenge is to advance not only in eco-compatibility but mainly in eco-sustainability, rooting the future of analytical chemistry in new paradigms which are founded on Life Cycle Thinking (LCT) and the resulting Life Cycle Assessment (LCA) of activities.

This Special Issue aims to collect studies that show the progress in analytical chemistry based on the arguments previously raised and discussed, with a particular reference to eco-compatibility and eco-sustainability. The expected contributions (original research papers and review articles) can include the development of low environmental impact methods and/or techniques or their applications, hyphenated technology, ambient-MS, but also interdisciplinary studies where the role of analytical techniques is well defined. In all the presented studies, it is appreciated that the environmental gain is clearly outlined.

Dr. Attilio Naccarato
Guest Editor

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Keywords

  • Green analytical chemistry (GAC)
  • Sustainable analytical chemistry (SAC)
  • Microextraction techniques
  • Ambient mass spectrometry (Ambient MS)
  • Life Cycle Thinking (LCT)
  • Life Cycle Assessment (LCA)
  • Circular economy
  • Natural products
  • Novel materials

Published Papers (13 papers)

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Editorial

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4 pages, 198 KiB  
Editorial
Development and Application of Green or Sustainable Strategies in Analytical Chemistry
by Attilio Naccarato
Separations 2023, 10(1), 32; https://0-doi-org.brum.beds.ac.uk/10.3390/separations10010032 - 05 Jan 2023
Viewed by 1145
Abstract
Analytical chemistry is bound to face growing challenges in the near future, especially for the quantification of trace analytes in complex matrices [...] Full article

Research

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12 pages, 4189 KiB  
Article
Facile Preparation of Phenyboronic-Acid-Functionalized Fe3O4 Magnetic Nanoparticles for the Selective Adsorption of Ortho-Dihydroxy-Containing Compounds
by Hongmei Zhou, Junhui Zhang, Aihong Duan, Bangjin Wang, Shengming Xie and Liming Yuan
Separations 2023, 10(1), 4; https://0-doi-org.brum.beds.ac.uk/10.3390/separations10010004 - 21 Dec 2022
Cited by 1 | Viewed by 1195
Abstract
A new facile strategy was designed to prepare the phenyboronic acid-functionalized Fe3O4 magnetic nanoparticles (Fe3O4@PBA) via direct silanization and thiol-ene click chemistry for the selective adsorption of ortho-dihydroxy-containing compounds. The three kinds of Fe3O [...] Read more.
A new facile strategy was designed to prepare the phenyboronic acid-functionalized Fe3O4 magnetic nanoparticles (Fe3O4@PBA) via direct silanization and thiol-ene click chemistry for the selective adsorption of ortho-dihydroxy-containing compounds. The three kinds of Fe3O4@PBA nanoparticles obtained showed excellent adsorption capacity and selectivity for ortho-dihydroxy-containing compounds including adenosine and o-dihydroxybenzene. Among them, the Fe3O4@MPS@MPBA exhibited the highest adsorption capacity and selectivity for adenosine and o-dihydroxybenzene, followed by Fe3O4@MPTES@AAPBA and Fe3O4@MPTES@VPBA. A synthesis method of superparamagnetic and boronate affinity nanocomposites with mild reaction conditions and simple process has been developed, which also provides a novel way for the synthesis of other types of enrichment materials of ortho-dihydroxy-containing compounds. Full article
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17 pages, 3861 KiB  
Article
Evaluation of Pulsed Electric Field-Assisted Extraction on the Microstructure and Recovery of Nutrients and Bioactive Compounds from Mushroom (Agaricus bisporus)
by Mara Calleja-Gómez, Juan Manuel Castagnini, Ester Carbó, Emilia Ferrer, Houda Berrada and Francisco J. Barba
Separations 2022, 9(10), 302; https://0-doi-org.brum.beds.ac.uk/10.3390/separations9100302 - 10 Oct 2022
Cited by 12 | Viewed by 2010
Abstract
Pulsed electric field (PEF) is a sustainable innovative technology that allows for the recovery of nutrients and bioactive compounds from vegetable matrices. A. bisporus was chosen for its nutritional value and the effect of PEF pretreatment was evaluated using different conditions of electric [...] Read more.
Pulsed electric field (PEF) is a sustainable innovative technology that allows for the recovery of nutrients and bioactive compounds from vegetable matrices. A. bisporus was chosen for its nutritional value and the effect of PEF pretreatment was evaluated using different conditions of electric field (2–3 kV/cm), specific energy (50–200 kJ/kg) and extraction time (0–6 h) to obtain the best conditions for nutrient and bioactive compound extraction. Spectrophotometric methods were used to evaluate the different compounds, along with an analysis of mineral content by inductively coupled plasma mass spectrometry (ICP-MS) and the surface was evaluated using scanning electron microscopy (SEM). In addition, the results were compared with those obtained by conventional extraction (under constant shaking without PEF pretreatment). After evaluating the extractions, the best extraction conditions were 2.5 kV/cm, 50 kJ/kg and 6 h which showed that PEF extraction increased the recovery of total phenolic compounds in 96.86%, carbohydrates in 105.28%, proteins in 11.29%, and minerals such as P, Mg, Fe and Se. These results indicate that PEF pretreatment is a promising sustainable technology to improve the extraction of compounds and minerals from mushrooms showing microporation on the surface, positioning them as a source of compounds of great nutritional interest. Full article
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11 pages, 1346 KiB  
Article
Comparison of Validation Parameters for the Determination of Vitamin D3 in Commercial Pharmaceutical Products Using Traditional and Greener HPTLC Methods
by Mohammed H. Alqarni, Faiyaz Shakeel, Ahmed I. Foudah, Tariq M. Aljarba, Aftab Alam, Sultan Alshehri and Prawez Alam
Separations 2022, 9(10), 301; https://0-doi-org.brum.beds.ac.uk/10.3390/separations9100301 - 09 Oct 2022
Cited by 1 | Viewed by 1475
Abstract
Several analytical methods are documented for the estimation of vitamin D3 (VD3) in pharmaceuticals, food supplements, nutritional supplements, and biological samples. However, greener analytical methods for VD3 analysis are scarce in the literature. As a consequence, attempts were made to design and validate [...] Read more.
Several analytical methods are documented for the estimation of vitamin D3 (VD3) in pharmaceuticals, food supplements, nutritional supplements, and biological samples. However, greener analytical methods for VD3 analysis are scarce in the literature. As a consequence, attempts were made to design and validate a greener “high-performance thin-layer chromatography (HPTLC)” method for VD3 estimation in commercial pharmaceutical products, as compared to the traditional HPTLC method. The greenness indices of both approaches were predicted by utilizing the “Analytical GREENness (AGREE)” method. Both traditional and greener analytical methods were linear for VD3 estimation in the 50–600 ng band−1 and 25–1200 ng band−1 ranges, respectively. The greener HPTLC strategy outperformed the traditional HPTLC strategy for VD3 estimation in terms of sensitivity, accuracy, precision, and robustness. For VD3 estimation in commercial tablets A–D, the greener analytical strategy was better in terms of VD3 assay over the traditional analytical strategy. The AGREE index of the traditional and greener analytical strategies was estimated to be 0.47 and 0.87, respectively. The AGREE analytical outcomes suggested that the greener analytical strategy had a superior greener profile to the traditional analytical strategy. The greener HPTLC strategy was regarded as superior to the traditional HPTLC methodology based on a variety of validation factors and pharmaceutical assays. Full article
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12 pages, 1631 KiB  
Article
Simultaneous Detection of Chlorzoxazone and Paracetamol Using a Greener Reverse-Phase HPTLC-UV Method
by Ahmed I. Foudah, Faiyaz Shakeel, Mohammed H. Alqarni, Tariq M. Aljarba, Sultan Alshehri and Prawez Alam
Separations 2022, 9(10), 300; https://0-doi-org.brum.beds.ac.uk/10.3390/separations9100300 - 09 Oct 2022
Cited by 4 | Viewed by 1638
Abstract
In the literature, greener/eco-friendly analytical techniques for simultaneous estimation of chlorzoxazone (CZN) and paracetamol (PCT) are scarce. As a consequence, greener reverse-phase high-performance thin-layer chromatography with ultraviolet (HPTLC-UV) detection was developed and validated for simultaneous estimation of CZN and PCT in commercial capsules [...] Read more.
In the literature, greener/eco-friendly analytical techniques for simultaneous estimation of chlorzoxazone (CZN) and paracetamol (PCT) are scarce. As a consequence, greener reverse-phase high-performance thin-layer chromatography with ultraviolet (HPTLC-UV) detection was developed and validated for simultaneous estimation of CZN and PCT in commercial capsules and tablets. The greenness of the proposed HPTLC-UV technique was assessed quantitatively by utilizing the “Analytical GREENness (AGREE)” methodology. For simultaneous estimation of CZN and PCT, the greener HPTLC-UV technique was linear in the 40–1600 ng band−1 and 30–1600 ng band−1 ranges, respectively. Furthermore, the suggested HPTLC-UV methodology proved sensitive, accurate, precise, and robust for simultaneous detection of CZN and PCT. The assay of CZN in marketed capsules and tablets was found to be 99.01 ± 1.53 and 100.87 ± 1.61%, respectively, using the suggested HPTLC-UV method. The assay of PCT in commercial capsules and tablets was found to be 98.31 ± 1.38 and 101.21 ± 1.67%, respectively. The AGREE index for the greener HPTLC-UV technique was found to be 0.79, suggesting an excellent greenness profile for the proposed HPTLC-UV technique. These results and data suggested the suitability of the greener HPTLC-UV methodology for simultaneous estimation of CZN and PCT in commercial formulations. Full article
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16 pages, 2756 KiB  
Article
Effective Solid Phase Extraction of Toxic Pyrrolizidine Alkaloids from Honey with Reusable Organosilyl-Sulfonated Halloysite Nanotubes
by Tobias Schlappack, Nina Weidacher, Christian W. Huck, Günther K. Bonn and Matthias Rainer
Separations 2022, 9(10), 270; https://0-doi-org.brum.beds.ac.uk/10.3390/separations9100270 - 29 Sep 2022
Cited by 6 | Viewed by 1535
Abstract
Pyrrolizidine alkaloids are plant secondary metabolites that have recently attracted attention as toxic contaminants in various foods and feeds as they are often harvested by accident. Furthermore, they prove themselves as hard to analyze due to their wide structural range and low concentration [...] Read more.
Pyrrolizidine alkaloids are plant secondary metabolites that have recently attracted attention as toxic contaminants in various foods and feeds as they are often harvested by accident. Furthermore, they prove themselves as hard to analyze due to their wide structural range and low concentration levels. However, even low concentrations show toxic behavior in the form of chronic liver diseases and possible carcinogenicity. Since sample preparation for this compound group is in need of more green and sustainable alternatives, modified halloysite nanotubes present an interesting approach. Based on the successful use of sulfonated halloysite nanotubes as inexpensive, easy-to-produce cation exchangers for solid phase extraction in our last work, this study deals with the further modification of the raw nanotubes and their performance in the solid phase extraction of pyrrolizidine alkaloids. Conducting already published syntheses of two organosilyl-sulfonated halloysite nanotubes, namely HNT-PhSO3H and HNT-MPTMS-SO3H, both materials were used as novel materials in solid phase extraction. After the optimization of the extraction protocol, extractions of aqueous pyrrolizidine alkaloid mixtures showed promising results with recoveries ranging from 78.3% to 101.3%. Therefore, spiked honey samples were extracted with an adjusted protocol. The mercaptopropyl-sulfonated halloysite nanotubes revealed satisfying loading efficiencies and recoveries. Validation was then performed, which displayed acceptable performance for the presented method. In addition, reusability studies using HNT-MPTMS-SO3H for solid phase extraction of an aqueous pyrrolizidine alkaloid mixture demonstrated excellent results over six cycles with no trend of recovery reduction or material depletion. Therefore, organosilyl-sulfonated halloysite nanotubes display a green, efficient and low-cost alternative to polymeric support in solid phase extraction of toxic pyrrolizidine alkaloids from complex honey matrix. Full article
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12 pages, 1662 KiB  
Article
Analytical Determination of Allergenic Fragrances in Indoor Air
by Catia Balducci, Marina Cerasa, Pasquale Avino, Paolo Ceci, Alessandro Bacaloni and Martina Garofalo
Separations 2022, 9(4), 99; https://0-doi-org.brum.beds.ac.uk/10.3390/separations9040099 - 13 Apr 2022
Cited by 1 | Viewed by 2244
Abstract
Among all the emerging contaminants, fragrances are gaining more relevance for their proven allergenic and, in some cases, endocrine-disrupting properties. To date, little information exists on their concentration in the air. This study aims to fill this gap by developing a method for [...] Read more.
Among all the emerging contaminants, fragrances are gaining more relevance for their proven allergenic and, in some cases, endocrine-disrupting properties. To date, little information exists on their concentration in the air. This study aims to fill this gap by developing a method for the determination of semivolatile fragrances in the indoor gaseous phase with sampling protocols usually adopted for the collection of atmospheric particulate matter (sampling time 24 h, flow rate 10 L min−1) and instrumental analysis by gas chromatography coupled with mass spectrometry. The method was developed on 66 analytes and tested at three concentration levels: 20 compounds showed analytical recoveries ≥72% with percentage standard deviations always better than 20%. For most compounds, negligible sampling breakthroughs were observed. The method was then applied to real samples collected in a coffee bar and in a private house. Considering the fragrances for which the method has shown good effectiveness, the highest concentrations were observed for carvone in the coffee bar (349 ng m−3) and camphor in the house (157 ng m−3). As concerns certain or suspected endocrine disruptors, lilyal and galaxolide were detected at both sites, α-isomethylionone was the second most concentrated compound in the house (63.2 ng m−3), musk xylene and musk ketone were present at lower concentration (≈ 1 or 2 ng m−3). Full article
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18 pages, 1393 KiB  
Article
The Crosslinker Matters: Vinylimidazole-Based Anion Exchange Polymer for Dispersive Solid-Phase Extraction of Phenolic Acids
by Matthias Harder, Rania Bakry, Felix Lackner, Paul Mayer, Christoph Kappacher, Christoph Grießer, Sandro Neuner, Christian W. Huck, Günther K. Bonn and Matthias Rainer
Separations 2022, 9(3), 72; https://0-doi-org.brum.beds.ac.uk/10.3390/separations9030072 - 08 Mar 2022
Cited by 1 | Viewed by 2189
Abstract
Crosslinkers are indispensable constituents for the preparation of SPE materials with ethylene glycol dimethacrylate (EGDMA) and divinylbenzene (DVB) among the most prominent representatives. A crosslinker that has not yet been used for the preparation of SPE sorbents is 3,3’-(hexane-1,6-diyl)bis(1-vinylimidazolium) bromide [C6-bis-VIM] [...] Read more.
Crosslinkers are indispensable constituents for the preparation of SPE materials with ethylene glycol dimethacrylate (EGDMA) and divinylbenzene (DVB) among the most prominent representatives. A crosslinker that has not yet been used for the preparation of SPE sorbents is 3,3’-(hexane-1,6-diyl)bis(1-vinylimidazolium) bromide [C6-bis-VIM] [Br]. In this study, we synthesized differently crosslinked vinylimidazole polymers with EGDMA, DVB and [C6-bis-VIM] [Br] and evaluated their extraction efficiencies towards phenolic acids. Dispersive SPE experiments performed with the [C6-bis-VIM] [Br] crosslinked polymers exhibited significantly higher extraction recoveries for the majority of analytes. Due to these promising results, the [C6-bis-VIM] [Br] crosslinked polymer was optimized in terms of the monomer to crosslinker ratio and an efficient dispersive SPE protocol was developed, with maximum recoveries ranging from 84.1–92.5% and RSD values ˂ 1%. The developed extraction procedure was also applied to cartridges resulting in recoveries between 97.2 and 98.5%, which were on average 5% higher than with the commercial anion exchange sorbent Oasis® MAX. Furthermore, the sorbent was regenerated showing a good reusability for the majority of analytes. In conclusion, this study clearly highlights the yet untapped potential of the crosslinker, [C6-bis-VIM] [Br], with respect to the synthesis of efficient anion exchange polymers for SPE. Full article
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17 pages, 4305 KiB  
Article
Study on the Preparation of Magnetic Mn–Co–Fe Spinel and Its Mercury Removal Performance
by Jiawei Huang, Zhaoping Zhong, Yueyang Xu and Yuanqiang Xu
Separations 2021, 8(11), 225; https://0-doi-org.brum.beds.ac.uk/10.3390/separations8110225 - 19 Nov 2021
Cited by 6 | Viewed by 2192
Abstract
In this study, the manganese-doped manganese–cobalt–iron spinel was prepared by the sol–gel self-combustion method, and its physical and chemical properties were analyzed by XRD (X-ray diffraction analysis), SEM (scanning electron microscope), and VSM (vibrating sample magnetometer). The mercury removal performance of simulated flue [...] Read more.
In this study, the manganese-doped manganese–cobalt–iron spinel was prepared by the sol–gel self-combustion method, and its physical and chemical properties were analyzed by XRD (X-ray diffraction analysis), SEM (scanning electron microscope), and VSM (vibrating sample magnetometer). The mercury removal performance of simulated flue gas was tested on a fixed bed experimental device, and the effects of Mn doping amount, fuel addition amount, reaction temperature, and flue gas composition on its mercury removal capacity were studied. The results showed that the best synthesized product was when the doping amount of Mn was the molar ratio of 0.5, and the average mercury removal efficiency was 87.5% within 120 min. Among the fuel rich, stoichiometric ratio, and fuel lean systems, the stoichiometric ratio system is most conductive to product synthesis, and the mercury removal performance of the obtained product was the best. Moreover, the removal ability of Hg0 was enhanced with the increase in temperature in the test temperature range, and both physical and chemical adsorption play key roles in the spinel adsorption of Hg0 in the medium temperature range. The addition of O2 can promote the removal of Hg0 by adsorbent, but the continuous increase after the volume fraction reached 10% had little effect on the removal efficiency of Hg0. While SO2 inhibited the removal of mercury by adsorbent, the higher the volume fraction, the more obvious the inhibition. In addition, in an oxygen-free environment, the addition of a small amount of HCl can promote the removal of mercury by adsorbent, but the addition of more HCl does not have a better promotion effect. Compared with other reported adsorbents, the adsorbent has better mercury removal performance and magnetic properties, and has a strong recycling performance. The removal efficiency of mercury can always be maintained above 85% in five cycles. Full article
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18 pages, 3387 KiB  
Article
Gum Arabic-Magnetite Nanocomposite as an Eco-Friendly Adsorbent for Removal of Lead(II) Ions from Aqueous Solutions: Equilibrium, Kinetic and Thermodynamic Studies
by Ismat H. Ali, Mutasem Z. Bani-Fwaz, Adel A. El-Zahhar, Riadh Marzouki, Mosbah Jemmali and Sara M. Ebraheem
Separations 2021, 8(11), 224; https://0-doi-org.brum.beds.ac.uk/10.3390/separations8110224 - 18 Nov 2021
Cited by 6 | Viewed by 2384
Abstract
In this study, a gum Arabic-magnetite nanocomposite (GA/MNPs) was synthesized using the solution method. The prepared nanocomposite was characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), and thermogravimetric analysis [...] Read more.
In this study, a gum Arabic-magnetite nanocomposite (GA/MNPs) was synthesized using the solution method. The prepared nanocomposite was characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), and thermogravimetric analysis (TGA). The prepared composite was evaluated for the adsorption of lead(II) ions from aqueous solutions. The controlling factors such as pH, contact time, adsorbent dose, initial ion concentration, and temperature were investigated. The optimum adsorption conditions were found to be 0.3 g/50 mL, pH = 6.00, and contact time of 30 min. The experimental data well fitted the pseudo-second-order kinetic model and the Langmuir isotherm model. The maximum adsorption capacity was determined as 50.5 mg/g. Thermodynamic parameters were calculated postulating an endothermic and spontaneous process and a physio-sorption pathway. Full article
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17 pages, 2307 KiB  
Article
Removal of Pyridine, Quinoline, and Aniline from Oil by Extraction with Aqueous Solution of (Hydroxy)quinolinium and Benzothiazolium Ionic Liquids in Various Ways
by Zhaojin Zhang, Yinan Li, Jing Gao, Alula Yohannes, Hang Song and Shun Yao
Separations 2021, 8(11), 216; https://0-doi-org.brum.beds.ac.uk/10.3390/separations8110216 - 12 Nov 2021
Cited by 2 | Viewed by 2451
Abstract
Based on above background, quinolinium, 8-hydroxy-quinolinium, and benzothiazolium ionic liquids, containing the acidic anions of methanesulfonate ([CH3SO3]), phosphate ([H2PO4]), p-toluenesulfonate ([p-TSA]), and bisulfate ([HSO4] [...] Read more.
Based on above background, quinolinium, 8-hydroxy-quinolinium, and benzothiazolium ionic liquids, containing the acidic anions of methanesulfonate ([CH3SO3]), phosphate ([H2PO4]), p-toluenesulfonate ([p-TSA]), and bisulfate ([HSO4]) were synthesized. After comparison, the aqueous solution of benzothiazole bisulfate [HBth][HSO4] was selected as the most ideal extractant for removing pyridine and aniline. Meanwhile, benzothiazole bisulfate [HBth][HSO4] solution was found as the best one for removing quinoline from simulated oil. Then, the single stage extraction and two-step extraction were used in the extraction for the simulated oil containing pyridine, quinoline or aniline, and their mixture, respectively. Their denitrogenation performance on their N-removal effect was compared on the basis of structural features, and main extraction conditions were further investigated, including mass ratio of IL to water, mass ratio of IL to oil, and temperature. Furthermore, the extraction process was described by two kinetic equations. Recovery and reuse of IL were realized by back-extraction and liquid-liquid separation, and a related mechanism was speculated, according to all the experimental results. Finally, based on the developed method for preparing complex adsorbent tablets, corresponding immobilized IL was used to remove target objects, by solid phase extraction, in order to extend separation ways, which was more easily recovered after extraction. Full article
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11 pages, 1016 KiB  
Article
A Simple Microextraction Method for Toxic Industrial Dyes Using a Fatty-Acid Solvent Mixture
by Danielle P. Arcon and Francisco C. Franco
Separations 2021, 8(9), 135; https://0-doi-org.brum.beds.ac.uk/10.3390/separations8090135 - 26 Aug 2021
Cited by 1 | Viewed by 1737
Abstract
A mixture of dodecanoic and hexanoic fatty acids was used to perform a simple and efficient microextraction method for industrial dyes such as methylene blue (MB), methyl violet (MV), and malachite green (MG) in aqueous solution. The fatty-acid microextractants were simply mixed and [...] Read more.
A mixture of dodecanoic and hexanoic fatty acids was used to perform a simple and efficient microextraction method for industrial dyes such as methylene blue (MB), methyl violet (MV), and malachite green (MG) in aqueous solution. The fatty-acid microextractants were simply mixed and heated until the mixture became homogeneous before adding it to the dye solutions. The fatty-acid solvent and its components were characterized with Fourier transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance (1H NMR) measurements, while the dye concentrations were measured using UV-Vis spectroscopy. The performance of the extracting mixture was observed to vary across different dye contaminants, dosages of the extractant, concentrations of the dyes, and contact times. High extraction efficiencies of up to ~99% were obtained for MG as well as MV, and ~73% efficiency was achieved for MB. The study shows how a mixture of fatty acids can be used as a simple, efficient, green, and sustainable low-volume method for the removal of toxic industrial dyes in aqueous solutions. Full article
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Review

Jump to: Editorial, Research

29 pages, 2234 KiB  
Review
Magnetic Ionic Liquids in Sample Preparation: Recent Advances and Future Trends
by Theodoros Chatzimitakos, Phoebe Anagnostou, Ioanna Constantinou, Kalliroi Dakidi and Constantine Stalikas
Separations 2021, 8(9), 153; https://0-doi-org.brum.beds.ac.uk/10.3390/separations8090153 - 13 Sep 2021
Cited by 12 | Viewed by 3196
Abstract
In the last decades, a myriad of materials has been synthesized and utilized for the development of sample preparation procedures. The use of their magnetic analogues has gained significant attention and many procedures have been developed using magnetic materials. In this context, the [...] Read more.
In the last decades, a myriad of materials has been synthesized and utilized for the development of sample preparation procedures. The use of their magnetic analogues has gained significant attention and many procedures have been developed using magnetic materials. In this context, the benefits of a new class of magnetic ionic liquids (MILs), as non-conventional solvents, have been reaped in sample preparation procedures. MILs combine the advantageous properties of ionic liquids along with the magnetic properties, creating an unsurpassed combination. Owing to their unique nature and inherent benefits, the number of published reports on sample preparation with MILs is increasing. This fact, along with the many different types of extraction procedures that are developed, suggests that this is a promising field of research. Advances in the field are achieved both by developing new MILs with better properties (showing either stronger response to external magnetic fields or tunable extractive properties) and by developing and/or combining methods, resulting in advanced ones. In this advancing field of research, a good understanding of the existing literature is needed. This review aims to provide a literature update on the current trends of MILs in different modes of sample preparation, along with the current limitations and the prospects of the field. The use of MILs in dispersive liquid–liquid microextraction, single drop microextraction, matrix solid-phase dispersion, etc., is discussed herein among others. Full article
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