Journal Description
Separations
Separations
- formerly Chromatography - is an international, peer-reviewed, open access journal on separation and purification science and technology in all areas of chemical, biological, physical science, and separation performance published monthly online by MDPI. The Central European Group of Separation Sciences (CEGSS) is affiliated with Separations and their members receive discounts on the article processing charges.
- Open Access— free for readers, with article processing charges (APC) paid by authors or their institutions.
- High Visibility: indexed within Scopus, SCIE (Web of Science), CAPlus / SciFinder, and other databases.
- Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 12.4 days after submission; acceptance to publication is undertaken in 2.8 days (median values for papers published in this journal in the first half of 2024).
- Recognition of Reviewers: reviewers who provide timely, thorough peer-review reports receive vouchers entitling them to a discount on the APC of their next publication in any MDPI journal, in appreciation of the work done.
- Companion journal: Purification.
Impact Factor:
2.5 (2023);
5-Year Impact Factor:
2.6 (2023)
Latest Articles
Ferulic Acid—A Brief Review of Its Extraction, Bioavailability and Biological Activity
Separations 2024, 11(7), 204; https://doi.org/10.3390/separations11070204 (registering DOI) - 1 Jul 2024
Abstract
Ferulic acid is a widespread phenolic compound that occurs in seeds and leaves, both in its free form and conjugated to polysaccharides, carbohydrates, glycoproteins and lignins in the plant cell walls. It exhibits various biological activities, like antioxidant, anticarcinogenic, anti-inflammatory, hepatoprotective, antimicrobial, and
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Ferulic acid is a widespread phenolic compound that occurs in seeds and leaves, both in its free form and conjugated to polysaccharides, carbohydrates, glycoproteins and lignins in the plant cell walls. It exhibits various biological activities, like antioxidant, anticarcinogenic, anti-inflammatory, hepatoprotective, antimicrobial, and antiviral activity, and it modulates enzyme activity. Given these wide potential health benefits, ferulic acid has attracted considerable research interest and may be considered a biomolecule with strong prospects as a functional food ingredient. Great attempts have been made to enhance its extraction process and recovery from natural matrices and agro-industrial wastes for its various applications relating to human health and nutrition. This review presents the recently available information on the extraction methods for quantifying ferulic acid in different samples, along with its bioavailability and stability in processing foods and biological activities.
Full article
(This article belongs to the Special Issue Bioactive Compounds in Foods: Separation, Extraction and Application)
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Open AccessReview
Dispersive Liquid–Liquid Micro Extraction: An Analytical Technique Undergoing Continuous Evolution and Development—A Review of the Last 5 Years
by
Ivan Notardonato and Pasquale Avino
Separations 2024, 11(7), 203; https://doi.org/10.3390/separations11070203 (registering DOI) - 28 Jun 2024
Abstract
Over the years, monitoring the quality of the environment, food, and human health has emerged as a fundamental objective of scientific investigation. Various analytical techniques have been devised and continually refined to ensure a high standard of living. Among these methods, dispersive liquid–liquid
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Over the years, monitoring the quality of the environment, food, and human health has emerged as a fundamental objective of scientific investigation. Various analytical techniques have been devised and continually refined to ensure a high standard of living. Among these methods, dispersive liquid–liquid microextraction (DLLME) stands out as a widely used approach to conduct analytical evaluations and pre-concentrations of chemical compounds. This review provides an account of the evolution of DLLME over the past five years (2018–2023). The Scopus search engine was used to search for scientific articles. The selection of relevant articles was carried out according to the criteria described below. Emphasis was placed on the evolution that DLLME has undergone over the years by integrating it with other pre-concentration methods in order to amplify the concentration factor and improve analytical precision. Factors such as solvent dispersion and extraction, dispersion formation, and the recovery of the solvent containing the extracted analytes were examined. Additionally, derivatization systems were evaluated to refine both qualitative and quantitative analysis. These efforts aim to introduce methods that are safe for operators, environmentally friendly, and economical. This review evaluates the advantages and disadvantages displayed by the evolution of this technique in the phases before, during, and after its application.
Full article
Open AccessArticle
Research on the Influence of the Scaling-up Process on the Flow Structure and Two-Phase Distribution of Gas–Solid Fluidized Beds
by
Zhonglin Gao, Jie Wei, Hongyang Wang and Chenyang Zhou
Separations 2024, 11(7), 202; https://doi.org/10.3390/separations11070202 - 28 Jun 2024
Abstract
In the continuous scaling-up process of the separating system, a mechanism exists that transforms the behavior of the flow field, resulting in deviations from the original model and conclusions. The paper examined the effects of the scale up of a fluidized bed by
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In the continuous scaling-up process of the separating system, a mechanism exists that transforms the behavior of the flow field, resulting in deviations from the original model and conclusions. The paper examined the effects of the scale up of a fluidized bed by CFD. It was observed that increasing the diameter reduces the amplitude of axial density fluctuations. Similarly, increasing the static height increases the amplitude. Moreover, increasing the static bed height enhances the visibility of the cyclic flow structure of gas and solid phases. The flow structure in large bed diameters is disrupted. The impact of changing the bed diameter on bed density is more significant than the static height. As the bed diameter increases, the bubble disturbance decreases and the aggregation phase gradually disappears while the proportion of the emulsified phase keeps increasing. This study will guide and assist in the future application of separated fluidized beds in industry.
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(This article belongs to the Special Issue Research Progress of Gas–Solid Fluidized Dry Separation)
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Open AccessArticle
Innovative Techniques in Sandalwood Oil Extraction: Optimizing Phenolic and Flavonoid Yields with Subcritical Ethanol
by
Weili Zhang, Dwila Nur Rizkiyah and Nicky Rahmana Putra
Separations 2024, 11(7), 201; https://doi.org/10.3390/separations11070201 - 27 Jun 2024
Abstract
Sandalwood essential oil, known for its rich content of phenolic and flavonoid compounds, holds great promise for applications in perfumery and medicine. However, traditional production methods have raised concerns regarding their environmental impact and sustainability. This study explored subcritical ethanol extraction as a
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Sandalwood essential oil, known for its rich content of phenolic and flavonoid compounds, holds great promise for applications in perfumery and medicine. However, traditional production methods have raised concerns regarding their environmental impact and sustainability. This study explored subcritical ethanol extraction as a green technique to address these concerns. Under optimized conditions (6.04 MPa, 109 °C, and 2.01 mL/min), maximum oil yield reached 4.04% with substantial total phenolic compounds (TPCs) of 4.11 mg GAE/100 g and total flavonoid compounds (TFCs) of 8.85 mg QE/100 g in the extracted sandalwood oil. Furthermore, the oil displayed notable antioxidant activity AA of 71.68%. The temperature was identified as a significant factor affecting oil yield, TPCs, TFCs, and AA. The fine-tuning of the extraction temperature enhanced the desired characteristics, improving bioactive compound yields and heightening antioxidant potential. This study uses a green extraction technique to contribute to sustainable sandalwood essential oil production.
Full article
(This article belongs to the Special Issue Advanced Extraction and Microextraction Techniques and Their Applications in Sample Preparation)
Open AccessArticle
A Simple and Efficient Approach to Determine Lithium and Multi-Elements in Lithium-Bearing Clay Minerals through a Partial Extraction Using Ammonium Hydrogen Fluoride
by
Feige Zhang, Qinfeng Zhang, Zhigui Chen, **aoqing Fang, **aoqi Yu, Guangyi Li and Di Chen
Separations 2024, 11(7), 200; https://doi.org/10.3390/separations11070200 - 27 Jun 2024
Abstract
Lithium (Li) is vital to the world economy as an irreplaceable element in new-generation sustainable energy applications. Quantifying Li levels in clay minerals, a key new resource, supports extensive mineralization surveys. The major limitation in these analyses is complete decomposition, which often requires
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Lithium (Li) is vital to the world economy as an irreplaceable element in new-generation sustainable energy applications. Quantifying Li levels in clay minerals, a key new resource, supports extensive mineralization surveys. The major limitation in these analyses is complete decomposition, which often requires the use of strong acids and is labor-intensive, particularly in batch processing. This paper presents a partial extraction strategy for quantifying Li and multiple elements, employing ammonium hydrogen fluoride to extract from clay minerals while avoiding the use of various strong acids. Following extraction, the efficiency for Li reaches 98.61%, with values ranging from 62.68% to 91.43% for multiple elements including three major elements (Ca, Fe, Mg) and eleven trace elements (Be, Co, Cr, Cu, Ga, Mn, Ni, P, Rb, Sr, V), demonstrating favorable precision (RSD below 7.34%). This approach offers a promising tool for a simple and efficient batch analysis in the survey of mineralization in Li-bearing clay deposits.
Full article
(This article belongs to the Special Issue Advanced Extraction and Microextraction Techniques and Their Applications in Sample Preparation)
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Open AccessArticle
Extraction of Bioactive Compound-Rich Essential Oil from Cistus ladanifer L. by Microwave-Assisted Hydrodistillation: GC-MS Characterization, In Vitro Pharmacological Activities, and Molecular Docking
by
Naoufal El Hachlafi, Fahd Kandsi, Amine Elbouzidi, Fatima Zahra Lafdil, Ghizlane Nouioura, Emad M. Abdallah, Rhizlan Abdnim, Mohamed Bnouham, Samiah Hamad Al-Mijalli, Hanae Naceiri Mrabti and Kawtar Fikri-Benbrahim
Separations 2024, 11(7), 199; https://doi.org/10.3390/separations11070199 - 27 Jun 2024
Abstract
Cistus ladanifer L. is an aromatic and resinous perennial shrub commonly used in Moroccan folk medicine against a range of illnesses including skin problems, diabetes, diarrhea, and inflammation. The current investigation aims to determine the bioactive compounds of C. ladanifer essential oil (CL-Eo)
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Cistus ladanifer L. is an aromatic and resinous perennial shrub commonly used in Moroccan folk medicine against a range of illnesses including skin problems, diabetes, diarrhea, and inflammation. The current investigation aims to determine the bioactive compounds of C. ladanifer essential oil (CL-Eo) extracted by microwave-assisted hydrodistillation and their biological properties using in vitro and molecular docking approaches. The GC-MS analysis identified linderol (17.76%), gamma-terpinene (17.55%), and borneol (13.78%) as main bioactive compounds. CL-Eo significantly inhibited α-amylase (IC50 = 0.41 ± 0.009 mg/mL), α-glucosidase (IC50 = 0.49 ± 0.002 mg/mL) and lipase (IC50 = 0.45 ± 0.004 mg/mL) enzymes. Moreover, CL-Eo showed significant hemoglobin glycation as well as antioxidant capacity as indicated by DPPH, ABTS, Frap and beta-carotene tests. The antimicrobial evaluation used disc-diffusion and microdilution tests in vitro. The results showed that CL-Eo had significant antibacterial activity, particularly against P. mirabilis (17.16 ± 1.04 mm), and moderate effects against L. innocua (13.48 ± 1.65 mm) and E. coli (12.47 ± 0.61 mm). In addition, it demonstrated potent antifungal activity against C. albicans (18.01 ± 0.91 mm) and C. tropicalis (16.45 ± 0.32 mm). The MIC and MBC tests provided confirmation that CL-Eo exhibited potent growth inhibition. The MIC ranged from 0.25 to 8.0% v/v and the MBC or MFC ranged from 0.25 to 16.0% v/v Eo. The tolerance level ratio showed bactericidal and fungicidal effects against tested microbial strains in varying degrees. According to these data, CL-Eo might be suggested as a promising candidate for drug development, specifically for combating candidiasis and diabetes.
Full article
(This article belongs to the Special Issue Extraction, Purification and Application of Bioactive Compounds)
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Open AccessArticle
Improved Expression of Aggregation-Prone Tau Proteins Using a Spidroin-Derived Solubility Tag
by
Kevin Muwonge, Bedri Yaman, Attila Mészáros, Giorgio Russo, Alexander Volkov and Peter Tompa
Separations 2024, 11(7), 198; https://doi.org/10.3390/separations11070198 - 25 Jun 2024
Abstract
Tauopathies, a group of neurodegenerative disorders, are characterized by the abnormal aggregation of microtubule-associated Tau proteins in neurons and glial cells. The process of Tau proteins transitioning from soluble, intrinsically disordered monomers to disease-associated aggregates is still unclear. Investigating these molecular mechanisms requires
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Tauopathies, a group of neurodegenerative disorders, are characterized by the abnormal aggregation of microtubule-associated Tau proteins in neurons and glial cells. The process of Tau proteins transitioning from soluble, intrinsically disordered monomers to disease-associated aggregates is still unclear. Investigating these molecular mechanisms requires the reconstitution of such processes in cellular and in vitro models using recombinant proteins at high purity and yield. However, the production of phase-separating or aggregation-prone recombinant proteins like Tau’s hydrophobic-rich domains or disease mutation-carrying variants on a large scale is highly challenging due to their limited solubility. To overcome this challenge, we have developed an improved strategy for expressing and purifying recombinant Tau proteins using the major ampullate spidroin-derived solubility tag (MaSp-NT*). This approach involves using NT* as a fusion tag to enhance the solubility and stability of expressed proteins by forming micelle-like particles within the cytosol of E. coli cells. We found that fusion with the NT* tag significantly increased the solubility and yield of highly hydrophobic and/or aggregation-prone Tau constructs. Our purification method for NT* fusion proteins yielded up to twenty-fold higher amounts than proteins purified using our novel tandem-tag (6xHis-SUMO-Tau-Heparin) purification system. This enhanced expression and yield were demonstrated with full-length Tau (hT40/Tau441), its particularly aggregation-prone repeat domain (Tau-MTBR), and Frontotemporal dementia (FTD)-associated mutant (Tau-P301L). These advancements offer promising avenues for the production of large quantities of Tau proteins suitable for in vitro experimental techniques such as nuclear magnetic resonance (NMR) spectroscopy without the need for a boiling step, bringing us closer to effective treatments for tauopathies.
Full article
(This article belongs to the Special Issue Peptide Synthesis, Separation and Purification)
Open AccessArticle
Simultaneous LC-MS/MS Method for the Quantitation of Probenecid, Albendazole, and Its Metabolites in Human Plasma and Dried Blood Spots
by
Mamunur Rashid, Yashpal S. Chhonker, Sandeep K. Singh and Daryl J. Murry
Separations 2024, 11(7), 197; https://doi.org/10.3390/separations11070197 - 25 Jun 2024
Abstract
Millions of individuals throughout the world suffer from lymphatic filariasis (LF), which is a morbid disease caused by Wuchereria bancrofti, Brugia malayi, and Brugia timori. These infections belong to tissue-invading nematodes and are one of the major neglected tropical diseases
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Millions of individuals throughout the world suffer from lymphatic filariasis (LF), which is a morbid disease caused by Wuchereria bancrofti, Brugia malayi, and Brugia timori. These infections belong to tissue-invading nematodes and are one of the major neglected tropical diseases that often result in permanent and enduring disability among individuals in endemic regions. Due to combination therapy, LF eradication has drastically decreased infections globally. The development of blood micro-sampling techniques allowing precise quantitation of drugs in blood would facilitate pharmacokinetic (PK) studies in remote populations. Therefore, an LC-MS/MS bioanalytical method was utilized to analyze albendazole (ABZ), albendazole sulfone (ABZ-ON), albendazole sulfoxide (ABZ-OX), and probenecid (PR) in plasma and dried blood spots. Solid-phase extraction was utilized to extract the analyte from both plasma and blood-spiked DBS. Analytes of interest were eluted with a gradient mobile system using 0.05% formic acid in water (A) and 0.05% formic acid in methanol (B) and separated using a reversed-phase Acquity ®BEH C18 UPLC column (100 × 2.1 mm, 1.7 µm). Precision and accuracy at each QC level were within the acceptable limit, i.e., ±15% for all analytes in both the matrices. Tests for stability under laboratory and storage conditions indicated that no notable changes were observed for plasma and DBS. The LC-MS/MS method demonstrated its capability to consistently identify all target analytes (ABZ, ABZ-ON, ABZ-OX, and PR) at low concentrations, even at the small specimen volumes obtained from DBS cards. This confirms the efficacy and durability of DBS cards as a micro-sampling technique. Moreover, it enhances collection efforts for therapeutic drug monitoring in remote locations for patients infected with lymphatic filariasis.
Full article
(This article belongs to the Special Issue Advances in Chemical Fingerprint Assessment and Analytical Isolation of Natural Products and Pharmaceuticals)
Open AccessReview
Summary of Pretreatment of Waste Lithium-Ion Batteries and Recycling of Valuable Metal Materials: A Review
by
Linye Li, Yuzhang Li and Guoquan Zhang
Separations 2024, 11(7), 196; https://doi.org/10.3390/separations11070196 - 25 Jun 2024
Abstract
The recycling of used lithium-ion batteries has become a growing concern. As a large number of rare metal elements are present in waste lithium-ion batteries, recycling them can significantly improve resource utilization and reduce the material cost of battery production. The process of
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The recycling of used lithium-ion batteries has become a growing concern. As a large number of rare metal elements are present in waste lithium-ion batteries, recycling them can significantly improve resource utilization and reduce the material cost of battery production. The process of recycling used lithium-ion batteries involves three main technology parts: pretreatment, material recovery, and cathode material recycling. Pretreatment includes discharge treatment, uniform crushing, and removing impurities. Material-recovery technology mainly involves traditional pyrometallurgical and hydrometallurgical technologies, as well as the develo** biometallurgy technology. Analysis of existing data shows that pretreatment technology is crucial for the recycling of used lithium-ion batteries. Hydrometallurgical technology and pyro-hydrometallurgical technology are expected to be the most suitable industrialization technology paths in the future, with biometallurgical technology and direct recycling technology providing a low-pollution development direction. This article summarizes the different pretreatment techniques and valuable metal-recovery pathways. The advantages and disadvantages of each method were evaluated. The economic costs, environmental benefits, and degree of industrialization of each method were assessed. The possible development directions of various methods are summarized to provide reference for future research.
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(This article belongs to the Section Analysis of Energies)
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Puerariae lobatae Radix: Progress in Extraction, Separation, and Pharmacological Activities Research
by
Erjian Gao, Wei Wang, Yuanyuan Huang, Zhijie Luo, Bangzheng Chen, Siqiu **ao and Dewen Li
Separations 2024, 11(7), 195; https://doi.org/10.3390/separations11070195 - 24 Jun 2024
Abstract
Kudzu root (Puerariae lobatae Radix) is the tuberous root of Pueraria lobata, family Leguminosae. Kudzu root contains a variety of beneficial active ingredients such as puerarin, daidzin, daidzein, genistenin, 3′-hydroxy puerarin, β-sitosterol, stigmasterol, arachidic acid, and so on. Modern medical research
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Kudzu root (Puerariae lobatae Radix) is the tuberous root of Pueraria lobata, family Leguminosae. Kudzu root contains a variety of beneficial active ingredients such as puerarin, daidzin, daidzein, genistenin, 3′-hydroxy puerarin, β-sitosterol, stigmasterol, arachidic acid, and so on. Modern medical research shows that active ingredients in kudzu root are widely used clinically as raw materials for the treatment of hyperglycemia, non-alcoholic fatty liver disease, myocardial infarction, alcohol addiction, oxidative stress, inflammatory response, and retinal blockage due to their various pharmacological effects such as improving cardiovascular circulation, lowering blood lipids, lowering blood pressure, lowering blood sugar, being antipyretic, being estrogen-like, and relieving alcohol. China has rich resources of kudzu root, and active ingredients are usually extracted before it is made into a preparation, so whether the extraction and separation process is reasonable will directly affect the ease of preparation and the efficacy of the treatment. This paper reviews the process methods for the extraction and separation of active ingredients in kudzu root and its common pharmacological activities. The aim is to provide some references for readers to compare the advantages and disadvantages of various extraction and separation methods as well as understand the active ingredients and pharmacological activities of kudzu root.
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(This article belongs to the Special Issue Advances in Chemical Fingerprint Assessment and Analytical Isolation of Natural Products and Pharmaceuticals)
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Open AccessArticle
Rapid Discovery of Antimicrobial and Antimalarial Agents from Natural Product Fragments
by
Jianying Han, Xueting Liu, Lixin Zhang, Wesley C. Van Voorhis, Ronald J. Quinn and Miaomiao Liu
Separations 2024, 11(7), 194; https://doi.org/10.3390/separations11070194 - 23 Jun 2024
Abstract
Fragment-based drug discovery (FBDD) focuses on small compounds, known as fragments, typically with a molecular weight of less than 300 Da. This study highlights the benefits of employing a pure natural product library for FBDD, contrasting with the predominant use of synthetic libraries.
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Fragment-based drug discovery (FBDD) focuses on small compounds, known as fragments, typically with a molecular weight of less than 300 Da. This study highlights the benefits of employing a pure natural product library for FBDD, contrasting with the predominant use of synthetic libraries. Practical methods for rapidly constructing such libraries from crude extracts were demonstrated across various plant and microbial samples. Twenty-nine (29) natural product fragments, including a new compound (20), were identified. Antimicrobial activities were assessed for a subset of the isolated compounds, revealing potent fragments (MICs 4–8 μg/mL) against Mycobacterium bovis bacille Calmette-Guérin (BCG), Staphylococcus aureus (SA), and methicillin-resistant S. aureus (MRSA). Furthermore, a native mass spectrometry technique was introduced to rapidly identify non-competitive fragments against malarial proteins. As a result, two pairs of non-competitive fragments, lepiotin C (31) and 7-amino deacetoxy cephalosporanic acid (32) binding to dynein light chain 1, methyl gallate (33) and β-santanin (34) binding to dUTPase, were identified, serving as promising starting points for develo** potent malarial protein inhibitors.
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(This article belongs to the Section Analysis of Natural Products and Pharmaceuticals)
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A Novel Solvent Microextraction Lab-in-Syringe System Coupled with Atomic Absorption Spectrometry for Thallium Determination in Water Samples
by
Arina Skok, Natalia Manousi, Yaroslav Bazel, Andriy Vishnikin and Aristidis Anthemidis
Separations 2024, 11(7), 193; https://doi.org/10.3390/separations11070193 - 21 Jun 2024
Abstract
Thallium is an accumulative highly toxic metal, that can be present in environmental samples due to industrial pollution and is dangerous for living organisms. Thus, its determination at trace levels is necessary. The lab-in-syringe (LIS) is considered to be a simple, functional, and
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Thallium is an accumulative highly toxic metal, that can be present in environmental samples due to industrial pollution and is dangerous for living organisms. Thus, its determination at trace levels is necessary. The lab-in-syringe (LIS) is considered to be a simple, functional, and versatile, technique that combines operational concepts and flow and sequential injection analysis. In this study, a liquid-phase microextraction LIS system was developed as a front-end to flame atomic absorption spectrometry (FAAS) for the determination of thallium in water samples. The proposed approach is based on the formation of Tl(III) ammonium–pyrrolidine–dithiocarbamate complex followed by its extraction using di-isobutyl-ketone. These procedures take place within the syringe barrel of the LIS system. The limit of detection of the developed method was 2.1 µg L−1 with a linear range from 7.0 to 400 µg L−1. The relative standard deviation (RSD) was 3.9% (at 50.0 µg L−1 Tl(I)), demonstrating good precision. Moreover, good method accuracy was obtained since the relative recovery values were within the range of 93.4–101.2%. Finally, reliable method applicability and green merits were demonstrated using the blue applicability grade index and green analytical procedure index, respectively. The proposed method was used for the analysis of environmental water samples.
Full article
(This article belongs to the Section Purification Technology)
Open AccessArticle
Study on the Efficiency of Fine Particle Removal in a Single-Tower Dual-Cycle Desulfurization Process Utilizing Heterogeneous Condensation
by
Rui Zhang, Zulpher Ahmad Mnipela, Linjun Yang and **aodong Si
Separations 2024, 11(7), 192; https://doi.org/10.3390/separations11070192 - 21 Jun 2024
Abstract
This study investigated a new method for controlling the emission of fine particles through heterogeneous condensation. Specifically, the research focuses on the application of single-tower double-cycle desulfurization technology in the wet flue gas desulfurization process. The establishment of a supersaturation environment necessary for
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This study investigated a new method for controlling the emission of fine particles through heterogeneous condensation. Specifically, the research focuses on the application of single-tower double-cycle desulfurization technology in the wet flue gas desulfurization process. The establishment of a supersaturation environment necessary for heterogeneous condensation was achieved by reducing the temperature of desulfurization slurry in the oxidation zone. Numerical simulations were used to study the distribution of the supersaturation degree and fluid dynamics characteristics in the desulfurization tower after the cooling of desulfurization slurry. Furthermore, the impact of single-tower double-cycle technology on the removal efficiency of fine particles was examined. The results of the numerical simulations indicate that cooling the desulfurization slurry in the absorption zone could establish a supersaturated vapor environment, with the supersaturation degree and region increasing as the slurry temperature decreases. Under typical operating conditions, a temperature drop of approximately 8~10 °C was found to be most suitable for the desulfurization slurry. Moreover, lowering the temperature of the desulfurization slurry in the absorption zone increases the supersaturation degree from 0.93 to 1.85. Additionally, the use of single-tower double-cycle desulfurization technology is shown to significantly enhance the removal efficiency of fine particles, particularly those within the particle size range of 0.1~1 μm. Ultimately, this method could increase the removal efficiency of fine particles from 39.9% to 57.9%.
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(This article belongs to the Collection Feature Paper Collection in Section 'Purification Technology')
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Investigation of the Distribution and Binding Affinity of Copper to Size-Fractioned Dissolved Organic Matter (DOM) in a Constructed Wetland
by
Ming-Yuan Hung, Wei-Hsiang Huang, Liang-Fong Hsu, Chi-Ying Hsieh and Ting-Chien Chen
Separations 2024, 11(6), 191; https://doi.org/10.3390/separations11060191 - 19 Jun 2024
Abstract
This study investigated the distribution and binding affinity of dissolved copper (Cu) and organic carbon (OC) in size-fractioned dissolved organic matter (DOM) in a constructed wetland (CW). Two sites were studied: one at the inflow (P-1) and one within the wetland (P-2). The
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This study investigated the distribution and binding affinity of dissolved copper (Cu) and organic carbon (OC) in size-fractioned dissolved organic matter (DOM) in a constructed wetland (CW). Two sites were studied: one at the inflow (P-1) and one within the wetland (P-2). The DOMs (<0.45 μm) were separated into six size fractions using a cross-flow ultrafiltration system. In the wetland (P-2), the concentrations of dissolved organic carbon (DOC) increased while the concentrations of Cu decreased. The high molecular weight fraction (1 kDa–0.45 μm, HMW) contained most of the OC mass (57.4–71.2% averages). On the other hand, Cu was almost equally distributed in HMW and low molecular weight fractions (<1 kDa, LMW) with mean HMW percentages of 50.3–51.3%. The mean Cu binding affinity to DOM ratios (CuBADOM) was 74.9 ± 24.0 μmol/g-C at site P-1 and 17.3 ± 2.6 μmol/g-C at site P-2. The CuBADOM ratios were decreased in wetlands of bulk and size-fractioned DOM (p < 0.001 to p = 0.073). The SUVA254 values for bulk DOM solution were 2.54 ± 0.15 and 1.68 ± 0.18 L/mg-C/m, and humidification index (HIX) values were 1.74 ± 0.16 and 2.09 ± 0.19 for sites P-1 and P-2, respectively. Optical indicators suggested that the wetland process decreased aromaticity but increased the humification degree of DOM. Furthermore, the CuBADOM ratios positively correlated with SUVA254 and HIX within the constructed wetland DOM but not in the influent DOM. Understanding the Cu distribution and binding affinity to size-fractioned DOM makes it possible to develop strategies to mitigate the potential effects of copper pollution in wetlands.
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(This article belongs to the Section Environmental Separations)
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Open AccessArticle
Application of Portable Near-Infrared Instrument for Analysis of Spirulina platensis Aqueous Extracts
by
Blaženko Marjanović, Tea Sokač Cvetnić, Davor Valinger, Maja Benković, Tamara Jurina, Jasenka Gajdoš Kljusurić and Ana Jurinjak Tušek
Separations 2024, 11(6), 190; https://doi.org/10.3390/separations11060190 - 18 Jun 2024
Abstract
Spirulina platensis microalga has become recognized as a promising source of highly nutritious food components to feed the growing global population. Because of its high protein content, abundance of essential amino acids, and excellent digestion, it is employed in human nutrition and there
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Spirulina platensis microalga has become recognized as a promising source of highly nutritious food components to feed the growing global population. Because of its high protein content, abundance of essential amino acids, and excellent digestion, it is employed in human nutrition and there is growing interest in analyzing bioactive compound present in Spirulina platensis microalga. In this work, a portable near-infrared (NIR) spectrometer was used for the monitoring of physicochemical properties (extraction yield (EY), total polyphenols concentration (TPC), total proteins concentration (TP), antioxidant activity measured by (i) the DPPH method (DPPH) and (ii) FRAP method (FRAP)) of Spirulina platensis aqueous extracts. The ultrasound-assisted aqueous extraction (ultrasonic bath with an ultrasound frequency of 35 kHz) of bioactive molecules from Spirulina platensis was performed throughout 30 independent experiments. NIR spectra were recorded in the wavelength range of 900–1700 nm. Raw NIR spectra were subjected to the physicochemical properties applying Principal Component Analysis (PCA), partial least square (PLS), and artificial neural network (ANN) modeling. Results show that ANN models developed for the prediction of TPC and DPPH can be utilized for extraction process control (RER > 10), while the other three models can be employed for screening (RER > 4). Generally, the obtained results indicate significant potential for using portable NIR spectroscopy for the analysis of Spirulina platensis aqueous extracts.
Full article
(This article belongs to the Special Issue Analysis, Isolation and Biological Activities of Polyphenols from Terrestrial and Marine Sources)
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Open AccessArticle
Enhanced Antioxidant Extraction from Lonicerae japonicae Flos Based on a Novel Optimization Strategy with Tailored Deep Eutectic Solvents
by
Wen-Wen Deng, Bo Sun, Han Yang, **ao-Jie Hou, Yong-Jian Zhang, Tian-**ang Gan, **n-Yi Cheng, Ao Yuan, **ao-Yang Dong, Cong-Yu Zhou, Ying Deng, Ya-Qian **ao, Reza Ghiladi, Hui Li and Jun Wang
Separations 2024, 11(6), 189; https://doi.org/10.3390/separations11060189 - 17 Jun 2024
Abstract
Lonicerae japonicae Flos (LJF) is a natural plant containing abundant antioxidant ingredients. In order to extract more antioxidants from LJF, in this study, a novel strategy was proposed for optimizing the extraction factor level by response surface methodology with a tailored deep eutectic
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Lonicerae japonicae Flos (LJF) is a natural plant containing abundant antioxidant ingredients. In order to extract more antioxidants from LJF, in this study, a novel strategy was proposed for optimizing the extraction factor level by response surface methodology with a tailored deep eutectic solvent (DES) as the extraction solvent and antioxidant ability as the evaluation index. After optimizing the composition of DES and the extraction condition, the extracts obtained by our proposed method yielded better antioxidant ability (229.1–249.1 μmol TE/g DW) and higher antioxidant contents (34.2–36.5 mg GAE/g DW for total phenolics and 119.6–123.0 mg RE/g DW for total flavonoids) from LJF in 5 min without organic solvent consumption that were significantly superior to the Chinese Pharmacopoeia extraction method. The K-T solvation parameter and a scanning electron microscope were adopted to explore the extraction mechanism, and the results showed that the polarity and damage effect on plant cells of DES were crucial for the extraction of antioxidants. In addition, after combining the HPLC fingerprint and partial least squares model, chlorogenic acid, rutin, and 3,5-O-Dicaffeoylquinic acid were screened as the antioxidant Q-markers of LJF. This work demonstrates that an optimization strategy based on antioxidant ability and tailored DES has the potential to extract more antioxidants from natural plants.
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(This article belongs to the Special Issue Extraction and Analysis of Chemical Compositions of Natural Products and Plants)
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Open AccessArticle
Simultaneous Determination of Multiresidues of Pesticides and Veterinary Drugs in Agricultural Soil Using QuEChERS and UHPLC–MS/MS
by
Michele C. Vicari, Janice F. Facco, Sandra C. Peixoto, Gabriel S. de Carvalho, Luana Floriano, Osmar D. Prestes, Martha B. Adaime and Renato Zanella
Separations 2024, 11(6), 188; https://doi.org/10.3390/separations11060188 - 14 Jun 2024
Abstract
Soil is one of the main destinations for pesticides and veterinary drugs used in agriculture and animal production. The negative consequences of the accumulation of these compounds in the environment make it important to monitor these compounds in the soil. In this study,
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Soil is one of the main destinations for pesticides and veterinary drugs used in agriculture and animal production. The negative consequences of the accumulation of these compounds in the environment make it important to monitor these compounds in the soil. In this study, we compared different extraction procedures using solvent shaking, ultrasound, or QuEChERS, and their combinations, for the simultaneous determination of 75 pesticide and seven veterinary drug residues in agricultural soil by ultra-high performance liquid chromatography coupled to serial mass spectrometry (UHPLC–MS/MS). The method using QuEChERS combined with shaking showed the best results for soil using the addition of water, followed by extraction with acetonitrile acidified with acetic acid and shaking in a shaker. For partitioning, anhydrous magnesium sulfate and anhydrous sodium acetate were used. The extract was centrifuged, filtered, and diluted (1:4, v/v) in water for determination by UHPLC–MS/MS. Method validation showed adequate accuracy and precision results, with recoveries between 70 and 120% and RSD ≤ 20% for the vast majority of the compounds evaluated at the spike levels of 10, 25, 50, and 100 μg kg−1. The method limits of detection (LOD) and quantification (LOQ) ranged from 3.0 to 7.5 μg kg−1 and from 10 to 25 μg kg−1, respectively. The method was applied to different agricultural soil samples and proved to be efficient for routine analysis.
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(This article belongs to the Collection Feature Paper Collection in Section 'Environmental Analysis')
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Open AccessArticle
The Important Role of Denitrifying Exoelectrogens in Single-Chamber Microbial Fuel Cells after Nitrate Exposure
by
**aojun **, Wenyi Wang, Zhuo Yan and Dake Xu
Separations 2024, 11(6), 187; https://doi.org/10.3390/separations11060187 - 14 Jun 2024
Abstract
Wastewater treatment using microbial fuel cells (MFCs) is a potentially useful technology due to its low cost, environmental friendliness, and low sludge production. In this study, a single-chambered air cathode MFC (SCMFC) was developed and investigated regarding its performance and microbial community evolution
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Wastewater treatment using microbial fuel cells (MFCs) is a potentially useful technology due to its low cost, environmental friendliness, and low sludge production. In this study, a single-chambered air cathode MFC (SCMFC) was developed and investigated regarding its performance and microbial community evolution following nitrate exposure. During long-term operation, diverse denitrifiers accumulated on the electrodes to form a denitrifying MFC (DNMFC) with stable activity for nitrate reduction. The DNMFC presented considerably higher electroactivity, stability, and denitrification rates than the SCMFC. Though energy recovery decreased in the DNMFC by partial organics utilized for heterotrophic denitrification, the electron transfer efficiency increased. Geobacter as the absolutely dominant genus in the SCMFC anode was eliminated and replaced by Azonexus and Pseudomonas in the DNMFC. Furthermore, the biomass of Pseudomonas (151.0 ng/μL) in the DNMFC cathode was five-fold higher than that in the SCMFC, although the bacterial community compositions were quite similar. The DNMFC with highly abundant Pseudomonas exhibited much better performance in terms of electrochemical activity and nitrate removal. The evolution process of functional bacteria from the SCMFC to the DNMFC comprehensively reveals the significant role of denitrifying electroactive bacteria in a bioelectrochemical system for nitrogen-containing wastewater treatment.
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(This article belongs to the Special Issue Bioelectrochemical Treatment and Purification of Wastewater)
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Open AccessReview
Green Technology for Fungal Protein Extraction—A Review
by
Tanvir Ahmed, Md Suzauddula, Khadiza Akter, Monir Hossen and Md Nazmul Islam
Separations 2024, 11(6), 186; https://doi.org/10.3390/separations11060186 - 13 Jun 2024
Abstract
Fungal proteins are highlighted for their nutritional value and bioactive properties, making them a significant alternative to traditional protein sources. This review evaluates various green extraction technologies, including enzymatic-, ultrasound-, higher-pressure homogenization-, microwave-assisted, pulsed electric fields-, and supercritical fluid-assisted extraction, focusing on their
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Fungal proteins are highlighted for their nutritional value and bioactive properties, making them a significant alternative to traditional protein sources. This review evaluates various green extraction technologies, including enzymatic-, ultrasound-, higher-pressure homogenization-, microwave-assisted, pulsed electric fields-, and supercritical fluid-assisted extraction, focusing on their effectiveness in disrupting fungal cell walls and preserving protein integrity. The findings indicate that these technologies could have the potential to improve protein yield and quality, addressing the challenges posed by fungal cell walls’ complex and resilient structure. The review also underscores the bioactivities of fungal proteins, including antifungal, antibacterial, antioxidant, and anticancer properties. The conclusion emphasises the need for further optimisation and scaling of these technologies, as well as exploring a wider range of fungal species to fully understand their potential as sustainable protein sources. Future research directions include refining extraction methods, integrating multiple approaches, and utilising novel green solvents to maximise efficiency and yield.
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(This article belongs to the Special Issue Advanced Extraction and Microextraction Techniques and Their Applications in Sample Preparation)
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Open AccessArticle
Aqueous Two-Phase Flotation Combined with Gold Nanoparticle Colorimetry for Determination of Thiocyanate in Raw Milk
by
Bin Jiang, Hongshen Yue, **nhao Fu, Jiaming Wang, Yu Feng, Chunhong Liu and Dongmei Li
Separations 2024, 11(6), 185; https://doi.org/10.3390/separations11060185 - 13 Jun 2024
Abstract
Thiocyanates are effective in inhibiting the growth of microorganisms in raw milk to extend shelf life, but excessive addition can cause human health problems. Currently, ion chromatography and spectrophotometry are the main methods used in industry to determine SCN, but the pre-treatment process
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Thiocyanates are effective in inhibiting the growth of microorganisms in raw milk to extend shelf life, but excessive addition can cause human health problems. Currently, ion chromatography and spectrophotometry are the main methods used in industry to determine SCN, but the pre-treatment process is cumbersome and time-consuming and has low sensitivity. Aqueous two-phase flotation (ATPF) technology has the advantages of simplicity, rapidity and economy. In this study, an acetonitrile/ammonium sulfate ATPF–gold nanoparticle (AuNP) colorimetric method was developed for the determination of SCN− in raw milk, and ATPF was used to separate and concentrate SCN− in raw milk to improve the detection sensitivity under convenient and economical conditions. The separation conditions were optimized by single-factor experiments and RSM, while the detection conditions, effects of CTAB concentration, pH and reaction time, were investigated. The “aggregation–anti-aggregation” mechanism of the gold-nano colorimetric method for the determination of SCN− was investigated by UV-vis absorption spectroscopy (UV-vis) and transmission electron microscopy (TEM). Under the optimal separation and detection conditions, the SCN− concentration showed a linear relationship with A630/A520 values in the concentration range of 0–2.5 mg/L with R2 of 0.9933, limit of detection (LOD) of 0.0919 mg/L, limit of quantitation (LOQ) of 0.306 mg/L, intra-day precision of 5.3% and spiked recoveries of 80.91–101.25%. In addition, the ATPF-AuNP colorimetric method demonstrated high selectivity and stability.
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(This article belongs to the Section Analysis of Food and Beverages)
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