Separations

10 pages, 5133 KiB

Open AccessArticle

Analysis of Marker Compounds in Lindera erythrocarpa from Diverse Geographical Regions of Korea

by Neil Patrick Uy, Jung-Hee Kim, Doo-Young Kim, Jajung Ku and Sanghyun Lee

Separations 2024, 11(8), 252; https://doi.org/10.3390/separations11080252 - 22 Aug 2024

Cited by 1 | Viewed by 621

Lindera erythrocarpa M., a medicinal plant commonly found in China, Japan, and Korea, is well known for its antioxidant, anti-inflammatory, and potential anti-cancer effects. However, data on the quantification of different marker compounds found in this species across plant parts and geographical regions [...] Read more.

Lindera erythrocarpa M., a medicinal plant commonly found in China, Japan, and Korea, is well known for its antioxidant, anti-inflammatory, and potential anti-cancer effects. However, data on the quantification of different marker compounds found in this species across plant parts and geographical regions remain limited. To address this gap in the literature, the marker compounds methyl lucidone (1), methyl linderone (2), and kanakugiol (3) in leaves and stems of L. erythrocarpa collected from five different regions in the Republic of Korea were analyzed using high-performance liquid chromatography (HPLC/UV). Among the three compounds analyzed, kanakugiol (3) was the most abundant and was predominantly found in the stem samples. Overall, stems contained higher concentrations of methyl linderone (2) and kanakugiol (3) than the leaves. These findings highlight the importance of considering regional factors and plant part selection to maximize the yield of bioactive compounds. The results support the potential of L. erythrocarpa as a medicinal source and contribute to the standardization and quality improvement of herbal goods, thereby enhancing consumer protection and product efficacy. Full article

(This article belongs to the Section Analysis of Natural Products and Pharmaceuticals)

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16 pages, 3820 KiB

Open AccessEditor’s ChoiceArticle

Simple Green Purification of Spilanthol from Natural Deep Eutectic Solvent and Ethanolic Acmella oleracea (L.) R.K. Jansen Extracts Using Solid-Phase Extraction

by Fabian Alperth, Sebastian Erhart, Olaf Kunert and Franz Bucar

Separations 2024, 11(8), 251; https://doi.org/10.3390/separations11080251 - 20 Aug 2024

Viewed by 782

Abstract

Spilanthol is a major N-alkylamide constituent of Acmella oleracea (L.) R.K. Jansen with diverse pharmacological properties. We recently showed the applicability of NADES (natural deep eutectic solvents) for the green extraction of spilanthol. However, the purification of targets from NADES poses a [...] Read more.

Spilanthol is a major N-alkylamide constituent of Acmella oleracea (L.) R.K. Jansen with diverse pharmacological properties. We recently showed the applicability of NADES (natural deep eutectic solvents) for the green extraction of spilanthol. However, the purification of targets from NADES poses a challenging step due to their non-volatility. A simple green method to retrieve spilanthol with minimal instrumental effort was devised, fractioning NADES (choline chloride/methylurea, choline chloride/1,2-propanediol, choline chloride/citric acid) and dry ethanolic extracts by SPE on C18 material, eluting merely with ethanolic solutions. The relative distribution of spilanthol and organic adulteration in SPE fractions were detected by HPLC-DAD, followed by scale-up, quantification and purity determination in an NMR-based approach. Isocratic elution with 52% ethanol (v/v) proved suitable in all experiments. The three purest 10 mL fractions combined yielded 12.21 mg spilanthol at 71.65% purity from NADES extract ChCl/P (choline chloride/1,2-propanediol, molar ratio 1:2, +20% m/m water). Ethanolic extract samples showed purities ranging from 77.27 to 80.27% in combined raw fractions. For all samples, purity increased by removing non-soluble substances from organic solutions. Pooled NADES extract fractions showed 89.71% in final samples, ethanolic extracts 87.25 to 91.93%. The highest purities of individual fractions per extract were 89.23 to 94.15%. This cheap and simple purification process is promising to acquire spilanthol for research purposes or as a sample preparation step before HPLC on a semi-preparative to preparative scale, as the substance is highly priced and scarcely available on the market. Organic solvents can be reused, and preliminary scale-up possibilities are shown. Full article

(This article belongs to the Special Issue Extraction and Analysis of Chemical Compositions of Natural Products and Plants)

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9 pages, 2093 KiB

Open AccessTechnical Note

Evaluation of Differences in Solubility in Organic Solvents of Softwood/Hardwood-Based Industrial Kraft Lignins Using Hansen Parameters and FTIR

by Klara Drame, Blaž Likozar and Giorgio Tofani

Separations 2024, 11(8), 250; https://doi.org/10.3390/separations11080250 - 19 Aug 2024

Viewed by 1221

Abstract

Lignin is part of the lignocellulosic biomass found in hardwoods, softwoods, and herbaceous plants. It is isolated by fractionation and pulping processes, where it is considered a waste product and is mainly burned to generate electricity and heat. However, lignin is a biopolymer [...] Read more.

Lignin is part of the lignocellulosic biomass found in hardwoods, softwoods, and herbaceous plants. It is isolated by fractionation and pulping processes, where it is considered a waste product and is mainly burned to generate electricity and heat. However, lignin is a biopolymer that can be a source of many chemicals of significant value after treatments of functionalisation or depolymerisation. The main processes for its valorisation require solubilisation in organic solvents, which may affect the process’s mass balance and the biopolymer’s chemical structure, as lignins are rarely completely soluble in organic solvents. In this research, two industrial Kraft lignins derived from softwood and hardwood were treated using different green organic solvents (2-methyl tetrahydrofuran, tetrahydrofuran, 1-methoxy-2-propanol, and acetone), measuring the soluble and insoluble content to determine the mass balance, and the solubility was evaluated using Hansen parameters and FTIR. The results showed that both lignins were more soluble in tetrahydrofuran and 1-methoxy-2-propanol. Also, tetrahydrofuran performed better than the 2-methyl tetrahydrofuran, which is considered the green alternative. The reason can be explained using the Hansen solubility parameters. Moreover, the solubilised fractions showed similar FTIR spectra. The same is the case for the insoluble parts. In conclusion, the two lignins studied showed different solubilities in absolute values in organic solvents, but the trends were similar. Full article

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17 pages, 7048 KiB

Open AccessArticle

An Extraction Process Based on the Collaborative Extraction of Coptis chinensis Franch. Phytoconstituents Using a Deep Eutectic Solvent and an Organic Solvent

by Cheng Liu, Fangyuan Gong, Zhengwei Xiong, Cun Wang, Xinhe Ran, Jiahua Ran, Runzi Li, Yangjin Ou, Qingqing Xia, Pei Wei and Jin Guo

Separations 2024, 11(8), 249; https://doi.org/10.3390/separations11080249 - 16 Aug 2024

Viewed by 854

Abstract

A low-cost method for the simultaneous extraction of alkaloids and water-insoluble flavonoids and esters from Coptis chinensis Franch. (Abbrev. C. chinensis) was explored to provide a reference for the production of green plant-based preparations and traditional Chinese medicine formula granules. A combined [...] Read more.

A low-cost method for the simultaneous extraction of alkaloids and water-insoluble flavonoids and esters from Coptis chinensis Franch. (Abbrev. C. chinensis) was explored to provide a reference for the production of green plant-based preparations and traditional Chinese medicine formula granules. A combined extraction method with the deep eutectic solvents (DESs) of choline chloride and urea (molar mass ratio of 1:2) and organic solvent ethanol was used, supplemented by ultrasonic-assisted extraction (ultrasonic power: 150 W; ultrasonic temperature: 60 °C; treatment time: 15 min). The extraction efficiency of the 50% DES (choline chloride and urea) aqueous solution for berberine, palmatine, jatrorrhizine, and magnoflorine was found to be the highest and was superior to traditional ultrasonic extraction and water bath reflux extraction methods. Furthermore, the flavonoids and esters from C. chinensis residue were extracted using ethanol. The results from high-performance liquid chromatography and gas chromatography–mass spectrometry indicated a high extraction efficiency overall. Full article

(This article belongs to the Special Issue Separation and Purification of Functional Components of Foods and Herbs)

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19 pages, 2061 KiB

Open AccessArticle

Development of an Enantioselective Method by Liquid Chromatography to Monitor 3,4-Methylenedioxypyrovalerone in Culture Media from Ecotoxicity Assays

by Ariana Pérez-Pereira, Virgínia M. F. Gonçalves, Ana R. L. Ribeiro, Carla Fernandes, João S. Carrola, Cláudia Ribeiro and Maria E. Tiritan

Separations 2024, 11(8), 248; https://doi.org/10.3390/separations11080248 - 16 Aug 2024

Viewed by 751

Abstract

3,4-Methylenedioxypyrovalerone (MDPV) is an emerging, chiral, new psychoactive substance belonging to the synthetic cathinones group that has been frequently detected in wastewater effluents and aquatic environments. However, the knowledge of its enantioselective occurrence and toxicity toward aquatic organisms is scarce. The aim of [...] Read more.

3,4-Methylenedioxypyrovalerone (MDPV) is an emerging, chiral, new psychoactive substance belonging to the synthetic cathinones group that has been frequently detected in wastewater effluents and aquatic environments. However, the knowledge of its enantioselective occurrence and toxicity toward aquatic organisms is scarce. The aim of this work was to develop an enantioselective liquid chromatography (LC) method to monitor the enantiomers of MDPV in environmental and ecotoxicological assays. For that, different chiral columns and mobile phases in both normal and reversed elution modes were attempted. The optimized conditions were achieved using a Daicel^® 3 μm—CHIRALPAK^® IF-3 column with 5 mM of ammonium bicarbonate (NH₄HCO₃, pH 8.8) in ultra-pure water (UPW) and acetonitrile (ACN) (10:90, v/v) as a mobile phase, at a flow rate of 0.3 mL min⁻¹. This condition was applied to monitor the racemate and the single enantiomers of MDPV in culture medium collected from ecotoxicity experiments. Racemization was observed for MDPV enantiomers (in individual exposure). The enantiomeric ratio (e.r.) of (S)-MDPV changed from an initial e.r. of 96.4/3.6 to 78.0/22.0 and for the (R)-enantiomer, the e.r changed from 15.6/84.4 to 28.3/71.7). These data highlight the importance of enantioselective monitoring of culture media in toxicity assays that involve chiral substances, since racemization can occur and lead to inaccuracy in the toxicity evaluation. Nevertheless, it is also important to stress that racemization may occur during storage conditions or sample procedures. Therefore, the enantioselective methodology is of utmost importance to warrant the quality of the results in enantioselective ecotoxicological studies. Full article

(This article belongs to the Collection Feature Paper Collection in Section 'Environmental Separations')

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14 pages, 4269 KiB

Open AccessArticle

Development and Characterization of SBA-15 Imprinted Polymers for Spiramycin Analysis

by Lorena González-Gómez, Sonia Morante-Zarcero, Damián Pérez-Quintanilla, Gema Paniagua González, Rosa M. Garcinuño, Pilar Fernández Hernando and Isabel Sierra

Separations 2024, 11(8), 247; https://doi.org/10.3390/separations11080247 - 15 Aug 2024

Viewed by 948

Abstract

This work focuses on the development of a hybrid material based on SBA-15 silica with a molecularly imprinted polymer (MIP), using spiramycin (SPI) as a template, for use as sorbent in solid-phase extraction (SPE). Characterization techniques such as nitrogen gas adsorption–desorption isotherms, infrared [...] Read more.

This work focuses on the development of a hybrid material based on SBA-15 silica with a molecularly imprinted polymer (MIP), using spiramycin (SPI) as a template, for use as sorbent in solid-phase extraction (SPE). Characterization techniques such as nitrogen gas adsorption–desorption isotherms, infrared spectroscopy and scanning electron microscopy confirmed the structure and properties of the SBA-15@MIP-SPI material. SPE conditions using SBA-15@MIP-SPI as sorbent were optimized, which allowed us to demonstrate the high selectivity and adsorption capacity of SPI on the synthesized material. The best conditions were 50 mg of sorbent, loading with 1 mL of standard solution or sample of cow milk previously extracted in acetonitrile and eluting with 3 mL of methanol with 1% acetic acid. After the optimization process, the material demonstrated recovery percentages of 81 ± 3% in SPI standard solutions and showed its potential in cow milk samples (71 ± 6%). The novelty of the research consists of the combination of MIPs with SBA-15, which could offer important advantages in terms of specific surface area and porous structure, thus improving performance and reducing the amount of sorbent compared to other traditional methods. Full article

(This article belongs to the Special Issue Novel Methods for the Analysis of Active and Toxic Components in Food)

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14 pages, 5092 KiB

Open AccessArticle

Development of a Voltammetric Methodology Based on a Methacrylic Molecularly Imprinted Polymer-Modified Carbon-Paste Electrode for the Determination of Aflatoxin B1

by Fabiola Hernández-García, Jesús Antonio Cruz-Navarro, Jesús García-Serrano, Miriam Franco-Guzmán, Gabriela Islas and Giaan A. Alvarez-Romero

Separations 2024, 11(8), 246; https://doi.org/10.3390/separations11080246 - 12 Aug 2024

Viewed by 745

Abstract

Aflatoxin B1 (AFB₁) is one of the most dangerous mycotoxins found in food, necessitating the development of precise and reliable methodologies for its detection. In this study, a novel electrochemical sensor based on a molecularly imprinted polymer (MIP) integrated with a [...] Read more.

Aflatoxin B1 (AFB₁) is one of the most dangerous mycotoxins found in food, necessitating the development of precise and reliable methodologies for its detection. In this study, a novel electrochemical sensor based on a molecularly imprinted polymer (MIP) integrated with a carbon-paste electrode was developed for the voltammetric determination of AFB₁. The innovative aspect of this work lies in the use of methacrylic acid (MAA) as the functional monomer, which enhances the sensor’s selectivity and binding affinity. The developed electrochemical sensor exhibited a linear response range from 20.8 to 80 ng/L, with a limit of detection (LOD) of 2.31 ng/L and a sensitivity of 19.83 µA (ng/L)⁻¹ cm⁻². The sensor demonstrated outstanding analytical performance, with reproducibility and repeatability yielding relative standard deviations (RSDs) of 3.24% and 1.41%, respectively. To validate the sensor’s practical applicability, its performance was tested in real samples of corn and wheat using the standard addition method. Samples were prepared following official Mexican standard methods. Detected AFB₁ concentrations were 0.0147 μg/L and 0.0138 μg/L for corn and wheat, respectively. A statistical comparison using the Student’s t-test confirmed no significant matrix effects, underscoring the high selectivity and accuracy of the MIP-modified sensor. This work introduces a highly selective, sensitive, and reproducible methodology for AFB₁ detection, which could significantly advance food safety monitoring. Full article

(This article belongs to the Special Issue Development of Materials for Separation and Analysis Applications)

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29 pages, 10900 KiB

Open AccessReview

Recent Developments of Pineapple Leaf Fiber (PALF) Utilization in the Polymer Composites—A Review

by Murugan Sethupathi, Mandla Vincent Khumalo, Sifiso John Skosana and Sudhakar Muniyasamy

Separations 2024, 11(8), 245; https://doi.org/10.3390/separations11080245 - 12 Aug 2024

Cited by 2 | Viewed by 4619

Abstract

Plant fibers’ wide availability and accessibility are the main causes of the growing interest in sustainable technologies. The two primary factors to consider while concentrating on composite materials are their low weight and highly specific features, as well as their environmental friendliness. Pineapple [...] Read more.

Plant fibers’ wide availability and accessibility are the main causes of the growing interest in sustainable technologies. The two primary factors to consider while concentrating on composite materials are their low weight and highly specific features, as well as their environmental friendliness. Pineapple leaf fiber (PALF) stands out among natural fibers due to its rich cellulose content, cost-effectiveness, eco-friendliness, and good fiber strength. This review provides an intensive assessment of the surface treatment, extraction, characterization, modifications and progress, mechanical properties, and potential applications of PALF-based polymer composites. Classification of natural fibers, synthetic fibers, chemical composition, micro cellulose, nanocellulose, and cellulose-based polymer composite applications have been extensively reviewed and reported. Besides, the reviewed PALF can be extracted into natural fiber cellulose and lignin can be used as reinforcement for the development of polymer biocomposites with desirable properties. Furthermore, this review article is keen to study the biodegradation of natural fibers, lignocellulosic biopolymers, and biocomposites in soil and ocean environments. Through an evaluation of the existing literature, this review provides a detailed summary of PALF-based polymer composite material as suitable for various industrial applications, including energy generation, storage, conversion, and mulching films. Full article

(This article belongs to the Special Issue Degradation and Separation of Fibre-Based Materials)

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2 pages, 138 KiB

Open AccessCorrection

Correction: Johnson et al. Phytochemical Profile of Asplenium aethiopicum (Burm. f.) Becherer Using HPTLC. Separations 2020, 7, 8

by Marimuthu alias Antonysamy Johnson, Janarthanan Gowtham, Narayanan Janakiraman, Tharmaraj Renisheya Joy Jeba Malar, Janaina E. Rocha and Henrique D. M. Coutinho

Separations 2024, 11(8), 244; https://doi.org/10.3390/separations11080244 - 12 Aug 2024

Viewed by 371

Abstract

In the original publication [...] Full article

(This article belongs to the Special Issue Applications of Chromatographic Techniques in Food and Environmental Analysis)

18 pages, 5252 KiB

Open AccessArticle

The Identification of Bioactive Compounds in the Aerial Parts of Agrimonia pilosa and Their Inhibitory Effects on Beta-Amyloid Production and Aggregation

by Chung Hyeon Lee, Min Sung Ko, Ye Seul Kim, Kwang Woo Hwang and So-Young Park

Separations 2024, 11(8), 243; https://doi.org/10.3390/separations11080243 - 9 Aug 2024

Viewed by 944

Abstract

Alzheimer’s disease (AD) is a progressive neurodegenerative condition characterized by memory and cognitive decline in older individuals. Beta-amyloid (Aβ), a significant component of senile plaques, is recognized as a primary contributor to AD pathology. Hence, substances that can inhibit Aβ [...] Read more.

Alzheimer’s disease (AD) is a progressive neurodegenerative condition characterized by memory and cognitive decline in older individuals. Beta-amyloid (Aβ), a significant component of senile plaques, is recognized as a primary contributor to AD pathology. Hence, substances that can inhibit Aβ production and/or accumulation are crucial for AD prevention and treatment. Agrimonia pilosa LEDEB. (A. pilosa) (Rosaceae), specifically its aerial parts, was identified in our previous screening study as a promising candidate with inhibitory effects on Aβ production. Therefore, in this study, A. pilosa extract was investigated for its anti-amyloidogenic effects, and its bioactive principles were isolated and identified. The ethanol extract of A. pilosa reduced the levels of sAPPβ and β-secretase by approximately 3% and 40%, respectively, compared to the DMSO-treated control group in APP-CHO cells (a cell line expressing amyloid precursor protein), which were similar to those in the positive control group. In addition, the ethanol extract of A. pilosa also hindered Aβ’s aggregation into fibrils and facilitated the disaggregation of Aβ aggregates, as confirmed by a Thioflavin T (Th T) assay. Subsequently, the active constituents were isolated using a bioassay-guided isolation method involving diverse column chromatography. Eleven compounds were identified—epi-catechin (1), catechin (2), (2S, 3S)-dihydrokaempferol 3-O-β-D-glucopyranoside (3), (-)-epiafzelechin 5-O-β-D-glucopyranoside (4), kaempferol 3-O-β-D-glucopyranoside (5), apigenin 7-O-β-D-glucopyranoside (6), dihydrokaempferol 7-O-β-D-glucopyranoside (7), quercetin 3-O-β-D-glucopyranoside (8), (2S, 3S)-taxifolin 3-O-β-D-glucopyranoside (9), luteolin 7-O-β-D-glucopyranoside (10), and apigenin 7-O-β-D-methylglucuronate (11)—identified through 1D and 2D NMR analysis and comparison with data from the literature. These compounds significantly decreased Aβ production by reducing β- and γ-secretase levels. Moreover, none of the compounds affected the expression levels of sAPPα or α-secretase. Further, compounds 1, 2, 4, 8, and 10 demonstrated a dose-dependent reduction in Aβ aggregation and promoted the disaggregation of pre-formed Aβ aggregates. Notably, compound 8 inhibited the aggregation of Aβ into fibrils by about 43% and facilitated the disassembly of Aβ aggregates by 41% compared to the control group containing only Aβ. These findings underscore the potential of A. pilosa extract and its constituents to mitigate a crucial pathological aspect of AD. Therefore, A. pilosa extract and its active constituents hold promise for development as therapeutics and preventatives of AD. Full article

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14 pages, 1625 KiB

Open AccessArticle

The Development and Validation of an LC–Orbitrap–HRMS Method for the Analysis of Four Tetracyclines in Milk and Its Application to Determine Oxytetracycline Concentrations after Intramuscular Administration in Healthy Sarda Ewes and Those Naturally Infected with Streptococcus uberis

by Severyn Salis, Simone Dore, Nicola Rubattu, Vittoria D’Ascenzo, Francesca T. Cherchi and Stefano A. Lollai

Separations 2024, 11(8), 242; https://doi.org/10.3390/separations11080242 - 8 Aug 2024

Viewed by 956

Abstract

An LC–Orbitrap–HRMS method was developed and validated for the simultaneous determination of four tetracyclines—oxytetracycline (OTC), tetracycline (TC), doxycycline (DC), and chlortetracycline (CTC)—in milk. This method involves sample extraction with McIlvaine–EDTA buffer solution (pH 4) and solid-phase extraction (SPE) with Oasis HLB cartridges, followed [...] Read more.

An LC–Orbitrap–HRMS method was developed and validated for the simultaneous determination of four tetracyclines—oxytetracycline (OTC), tetracycline (TC), doxycycline (DC), and chlortetracycline (CTC)—in milk. This method involves sample extraction with McIlvaine–EDTA buffer solution (pH 4) and solid-phase extraction (SPE) with Oasis HLB cartridges, followed by the evaporation of the extract and its reconstitution with a 14% methanol aqueous solution before injection into the instrumental system. This method has been validated in terms of linearity, sensitivity, selectivity, precision, and accuracy, in accordance with Commission Decision 2002/657/EC requirements. Compared to existing methods, this approach optimally combines a quantitative procedure for extracting analytes from the milk of different species, including sheep, bovines, and goats, with a very short LC–Orbitrap–HRMS instrumental analysis time (only 8 min), simultaneously ensuring high precision, sensitivity, and applicability as a rapid confirmation method in official food control laboratories. The proposed method was applied to determine the concentration levels of OTC in milk samples derived from healthy Sardinian sheep and those naturally infected with Streptococcus uberis, after the intramuscular administration of an antibiotic, in order to evaluate how much of the drug was “subtracted” during penetration from blood into milk, with a potential effect of reducing its therapeutic efficacy. Full article

(This article belongs to the Special Issue Application of Liquid Chromatography in Pharmaceutical and Toxicological Analysis)

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16 pages, 1297 KiB

Open AccessEditor’s ChoiceArticle

Polyphenols Extraction from Different Grape Pomaces Using Natural Deep Eutectic Solvents

by Alessandro Frontini, Andrea Luvisi, Carmine Negro, Massimiliano Apollonio, Rita Accogli, Mariarosaria De Pascali and Luigi De Bellis

Separations 2024, 11(8), 241; https://doi.org/10.3390/separations11080241 - 8 Aug 2024

Viewed by 1255

Abstract

Exploiting by-products from the oenological industry to extract antioxidant chemicals is a shared goal that combines the need to reduce the wine sector’s environmental impact with the need to improve the availability of these biomolecules, according to a circular economy approach. Natural deep [...] Read more.

Exploiting by-products from the oenological industry to extract antioxidant chemicals is a shared goal that combines the need to reduce the wine sector’s environmental impact with the need to improve the availability of these biomolecules, according to a circular economy approach. Natural deep eutectic solvents (NaDES) have recently captured researchers’ interest as a safer and more environmentally friendly alternative to traditional solvents due to their effectiveness, low toxicity, and stability. In this work, we set out to investigate several NaDES for the extraction of phenolic chemicals from local monovarietal grape pomace resulting from different vinification procedures (including both red and rosé vinification of Negroamaro and Primitivo grapes; rosé vinification of Susumaniello grapes and white vinification of Chardonnay, Fiano and Malvasia bianca grapes), with the additional goal of generalizing the use of NaDES to extract chemicals of interest from organisms selected from the wide plant biodiversity. Three binary choline chloride-based NaDES (DES-Lac, DES-Tar, and DES-Gly, with lactic acid, tartaric acid, and glycerol as hydrogen bond donors, respectively) were compared to ethanol as a conventional solvent, and the extracts were evaluated using HPLC/MS and colorimetric techniques. The results revealed that each NaDES produces a substantially higher total phenolic yield than ethanol (up to 127.8 mg/g DW from Primitivo rosé grape pomace). DES-Lac and DES-Tar were more effective for anthocyanins extraction; the most abundant compound was malvidin 3-O-glucoside (highest extraction yield with DES-Lac from Susumaniello pomace: 29.4 mg/g DW). Regarding phenolic compounds, DES-Gly was the most effective NaDES producing results comparable to ethanol. Unexpectedly, Chardonnay pomace has the greatest content of astilbin. In most cases, grape pomace extracts obtained by rosé and white vinification provided the maximum yield. As a result, NaDES have emerged as a viable alternative to traditional organic solvent extraction techniques, allowing for higher (or equal) yields while significantly lowering costs, hazards, and environmental impact. Full article

(This article belongs to the Special Issue Extraction and Characterization of Bioactive Compounds from Plant and Natural Sources)

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15 pages, 2344 KiB

Open AccessArticle

A Validated Method for the Simultaneous Determination of Oxytocin and Cortisol in Human Saliva

by Elisa Polledri, Rosa Mercadante, Laura Campo and Silvia Fustinoni

Separations 2024, 11(8), 240; https://doi.org/10.3390/separations11080240 - 6 Aug 2024

Viewed by 675

Abstract

Oxytocin and cortisol (OXY and CORT) are hormones related to stress, cognitive, and social behaviors. Their detection is relevant to epidemiological studies aimed at investigating the effects of stressor factors on human life. The aim of this study was to develop and validate [...] Read more.

Oxytocin and cortisol (OXY and CORT) are hormones related to stress, cognitive, and social behaviors. Their detection is relevant to epidemiological studies aimed at investigating the effects of stressor factors on human life. The aim of this study was to develop and validate an assay for the measurement of OXY and CORT in saliva samples using liquid chromatography/tandem mass spectrometry (LC-MS/MS) in the presence of deuterated analogs. A 500 mL aliquot of oral fluid, obtained by the centrifugation of a chewed swab, was purified by solid-phase extraction. Analytes were then separated using C18 reversed-phase chromatography, subjected to positive electrospray ionization, and then quantified using a triple-quadrupole mass detector in multiple-reaction monitoring mode. The limits of quantification and the linear dynamic ranges were 2.0 × 10⁻³ and 0.5 nmol/L, and up to 1.0 × 10⁻¹ and 20 nmol/L for OXY and CORT, respectively. Inter- and intra-run precision, expressed as relative standard deviation, was <7%, and accuracy was within 93–104% of the theoretical concentrations. The evaluation of matrix effects showed that the use of internal standards controlled sources of bias. The high sensitivity of the method allowed the quantification of OXY and CORT in the salivary samples of both adults and children: levels of CORT ranged from 0.6 to 18.5 nmol/L, while OXY levels were two orders of magnitude lower (from 1.7 × 10⁻³ to 1.1 × 10⁻² nmol/L). To our knowledge, this is the first method that can analyze, in the same chromatographic run, both hormones in saliva samples. Full article

(This article belongs to the Section Bioanalysis/Clinical Analysis)

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13 pages, 1566 KiB

Open AccessArticle

Determination of Gb3 and Lyso-Gb3 in Fabry Disease-Affected Patients by LC-MRM/MS

by Gennaro Battaglia, Gabriella Pinto, Carolina Fontanarosa, Michele Spinelli, Anna Illiano, Stefania Serpico, Lorenzo Chiariotti, Roberta Risoluti, Stefano Materazzi and Angela Amoresano

Separations 2024, 11(8), 239; https://doi.org/10.3390/separations11080239 - 6 Aug 2024

Viewed by 1167

Abstract

Limited or absent activity of the enzyme α-galactosidase A (α-Gal A), due to mutation in the related gene on the X chromosome, leads to the development of a rare hereditary and genetic disease known as Fabry disease (FD). This pathology involves a progressive [...] Read more.

Limited or absent activity of the enzyme α-galactosidase A (α-Gal A), due to mutation in the related gene on the X chromosome, leads to the development of a rare hereditary and genetic disease known as Fabry disease (FD). This pathology involves a progressive accumulation in various organs of the substrates of the enzyme e.g., globotriaosylceramide (Gb3) and its deacylated form, globotriaosylsphingosine (Lyso-Gb3), suggesting these molecules as biomarkers of Fabry disease. The present paper describes the development of an analytical strategy for the identification and quantification of Gb3 and Lyso-Gb3, in serum and blood samples by using liquid chromatography (LC) coupled to mass spectrometry in multiple reaction monitoring (MRM/MS) ion mode. The best experimental conditions were obtained by extracting the glycolipids with chloroform/methanol/H₂O (2/1/0.3) and by separating them on a C4 column with a linear gradient (A: H₂O with 2 mM ammonium formate. B: methanol with 1 mM ammonium formate, both acidified with 0.2% formic acid). The best transitions (a combination of precursor and fragment ions—m/z) were 786.8 m/z > 268.3 m/z for Lyso-GB3, 1137.3 m/z > 264.3 m/z for Gb3, 1039.3 m/z > 264.4 m/z for N-heptadecanoyl-ceramide trihexoside, and 843.5 m/z > 264.3 m/z for N-glycinated lyso-ceramide trihexoside, the latter being used as an internal standard. The developed method provided a reliable, fast, and effective procedure for direct measurements of GB3 and Lyso-GB3 in serum and blood for diagnosis of Fabry disease, suggesting this method as a complementary assay to the current enzymatic test. Therefore, this approach could open new insights into the clinical diagnostics of lysosomal storage disorders. Full article

(This article belongs to the Section Bioanalysis/Clinical Analysis)

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20 pages, 2588 KiB

Open AccessArticle

Fish Extract Fractionation by Solid Phase Extraction: Investigating Co-Occurring Ciguatoxins by LC-MS/MS and N2a-Bioassay

by Astrid Spielmeyer, Vincent Blaschke and Christopher R. Loeffler

Separations 2024, 11(8), 238; https://doi.org/10.3390/separations11080238 - 1 Aug 2024

Cited by 1 | Viewed by 935

Abstract

Ciguatoxins (CTXs) are neurotoxic marine biotoxins capable of contaminating marine organisms. Approximately 30 CTX analogues have been described; however, only a few have been documented in ciguatera poisoning (CP) outbreaks. Detecting CTXs from complex matrices at CP-relevant concentrations (<1 µg per kg seafood [...] Read more.

Ciguatoxins (CTXs) are neurotoxic marine biotoxins capable of contaminating marine organisms. Approximately 30 CTX analogues have been described; however, only a few have been documented in ciguatera poisoning (CP) outbreaks. Detecting CTXs from complex matrices at CP-relevant concentrations (<1 µg per kg seafood tissue) is analytically challenging. Analytical standards for CTXs are rare. Even after multi-step sample preparation (including liquid–liquid partition, defatting, and solid-phase extraction (SPE)), extracts can contain undesirable co-eluting matrix components. These limitations can exacerbate discrepancies between results obtained by LC-MS/MS and the N2a-bioassay, which are two common CTX detection methods. Herein, a rapid and simple fractionation method, based on normal phase SPE (silica), is demonstrated. Target CTXs were eluted using solvent mixtures of ascending polarity, passed through the column, and separated into eight fractions. To challenge the method, extracts with eleven naturally incurred CTX analogues among different structural CTX groups (e.g., CTX3C, CTX4A, and C-CTX group) were used. The most complex tissue matrix tested (viscera) was improved the most for extract purity and CTX detection, enhancing the correlation between LC-MS/MS and N2a-bioassay results. This workflow represents an advancement for characterizing CTXs in seafood products and CP outbreaks, irrespective of the responsible CTX analogue and where standards are lacking. Full article

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34 pages, 2751 KiB

Open AccessArticle

Characterisation of the Volatile Compounds and Key Odourants in Japanese Mandarins by Gas Chromatography–Mass Spectrometry and Gas Chromatography–Olfactometry

by Lingyi Li, Rui Min Vivian Goh, Yunle Huang, Kim-Huey Ee, Aileen Pua, Daphne Tan, Shanbo Zhang, Lionel Jublot, Shao Quan Liu and Bin Yu

Separations 2024, 11(8), 237; https://doi.org/10.3390/separations11080237 - 1 Aug 2024

Viewed by 1100

Abstract

Japanese mandarins are becoming increasingly popular due to their pleasant aroma. The volatiles in four varieties of Japanese mandarins (Iyokan, Ponkan, Shiranui, and Unshiu mikan) were extracted by headspace solid-phase microextraction (HS-SPME) and solvent extraction, then analysed by gas chromatography–mass spectrometry (GC-MS). Principal [...] Read more.

Japanese mandarins are becoming increasingly popular due to their pleasant aroma. The volatiles in four varieties of Japanese mandarins (Iyokan, Ponkan, Shiranui, and Unshiu mikan) were extracted by headspace solid-phase microextraction (HS-SPME) and solvent extraction, then analysed by gas chromatography–mass spectrometry (GC-MS). Principal component analysis (PCA) of the GC-MS data demonstrated distinct segregation of all four Japanese mandarin varieties. Esters, such as neryl acetate, distinguished Iyokan. Methylthymol uniquely characterised Ponkan, valencene was exclusive to Shiranui, and acids like hexanoic acid and heptanoic acid differentiated Unshiu mikan from the other three varieties. Aroma extract dilution analysis (AEDA) revealed 131 key odourants across four Japanese mandarins, including myrcene (peppery, terpenic), perillyl alcohol (green, spicy, floral), trans-nerolidol (sweet, floral), and trans-farnesol (woody, floral, green). Finally, sensory evaluation was conducted on the four Japanese mandarin peel extracts to describe the distinct aroma profile of each variety of Japanese mandarin: Iyokan had higher floral and juicy notes, Ponkan showed higher sulphury notes, Shiranui was perceived to have more albedo notes, and Unshiu mikan exhibited higher peely, green, and woody notes. Full article

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15 pages, 1481 KiB

Open AccessArticle

Chemical Composition and Biological Properties of Achillea cucullata Extracts from Leaves and Flowers

by Manal Abdulaziz Binobead and Ibrahim M. Aziz

Separations 2024, 11(8), 236; https://doi.org/10.3390/separations11080236 - 1 Aug 2024

Viewed by 861

Abstract

Achillea cucullata is a perennial herbaceous plant that has a long history of medical use in many cultures. The present research focuses on the biological activity and therapeutic potential of A. cucullata, namely its antibacterial and anticancer properties. While previous studies have [...] Read more.

Achillea cucullata is a perennial herbaceous plant that has a long history of medical use in many cultures. The present research focuses on the biological activity and therapeutic potential of A. cucullata, namely its antibacterial and anticancer properties. While previous studies have shed light on the cytotoxic and antibacterial capabilities of Achillea cucullata aerial parts, there is still a considerable gap in knowledge concerning the anticancer potential of leaf and flower extracts. A. cucullata’s leaves and flowers were extracted using methanol. The total phenolic and flavonoid contents were evaluated. The antioxidant, cytotoxic, and antibacterial properties were evaluated against both Gram-positive and Gram-negative bacteria. The Gas Chromatography–Mass Spectrometry (GC–MS) analysis of A. cucullata leaf and flower extracts showed numerous amounts of bioactive components, including carvacrol, a TBDMS derivative; 2-Myristynoyl-glycinamide, acetylaminobenzothiazol-2-yl)-2-(adamantan-1-yl); Isolongifolol; (3E,10Z)-Oxacyclotrideca-3,10-diene-2,7-dione; and 3-Heptanone, 5-hydroxy-1,7-diphenyl. The extract has a high level of phenols and flavonoids. Cytotoxicity studies found that A. cucullata leaves and flowers had dose-dependent toxicity against MCF-7 and HepG2 cancer cell lines, with flowers being more effective. Apoptotic genes (caspase-3, 8, 9, and Bax) were upregulated in treated MCF-7 and HepG2 cells, whereas anti-apoptotic genes (Bcl-xL and Bcl-2) were reduced. Antibacterial screening revealed significant activity against both Gram-positive and Gram-negative pathogens. Overall, the research highlights the varied therapeutic potentials of A. cucullata, adding to the knowledge of plant-derived extracts in lowering disease risks. Future research should concentrate on in vivo studies to assess the effectiveness and safety of these substances. Full article

(This article belongs to the Special Issue Extraction, Purification and Application of Bioactive Compounds)

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12 pages, 1288 KiB

Open AccessEditor’s ChoiceArticle

Evolution of Eight Biogenic Amines in Raw and Preserved Mackerel (Scomber scombrus) Fillets Monitored by UHPLC-PDA

by Laura Barp, Erica Moret and Sabrina Moret

Separations 2024, 11(8), 235; https://doi.org/10.3390/separations11080235 - 1 Aug 2024

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Abstract

The presence of biogenic amines (BAs) in seafood can pose a health risk to consumers, as they have been linked to adverse reactions such as histamine poisoning. Although the only biogenic amine for which maximum limits have been set is histamine, it is [...] Read more.

The presence of biogenic amines (BAs) in seafood can pose a health risk to consumers, as they have been linked to adverse reactions such as histamine poisoning. Although the only biogenic amine for which maximum limits have been set is histamine, it is also important to regulate the presence of other amines associated with certain adverse effects. In this study, the official method for determining histamine was slightly modified and adapted for a UHPLC-PDA system and applied to analyze raw and preserved mackerel fillet samples. The evolution of biogenic amines during the storage period under refrigerated conditions revealed that, within two days, the limit for the content of histidine of 100 mg/kg was exceeded in raw fillets, while the histidine content in preserved mackerel (in oil and marinated) remained more stable. The thawing phase, whether in the fridge or at room temperature, did not significantly affect the BA content. Additionally, three different cooking methods (steaming, oven-baking, and boiling) significantly decrease the levels of BAs in highly contaminated raw mackerel fillets. Full article

(This article belongs to the Special Issue Determination of Potentially Toxic Elements in Food, Beverage and Medicinal Plants by Analytical Methods and Separation Technologies)

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16 pages, 8600 KiB

Open AccessArticle

Investigation of Flotation Bubbles Movement Behavior under the Influence of an Immersed Ultrasonic Vibration Plate

by Kuidong Gao, Wenchao Zong, Zhihua Zhang, Liqing Sun and Lin Li

Separations 2024, 11(8), 234; https://doi.org/10.3390/separations11080234 - 31 Jul 2024

Viewed by 861

Abstract

Ultrasonic flotation is widely used as an efficient mineral separation method. Its efficiency is related to the adhesion behavior between fine particles and flotation bubbles, which can be influenced by the bubbles’ movement behavior. This paper used two immersed ultrasonic vibration plates to [...] Read more.

Ultrasonic flotation is widely used as an efficient mineral separation method. Its efficiency is related to the adhesion behavior between fine particles and flotation bubbles, which can be influenced by the bubbles’ movement behavior. This paper used two immersed ultrasonic vibration plates to generate ultrasonic action and investigated the effect of ultrasonic action on the rising process of flotation bubbles. The distribution, aggregation and fusion, velocity, and other characteristics of bubbles generated by different needle apertures were studied by experimental and simulation methods. The results showed that a 0.4 mm needle produced bubbles that were more evenly spaced and more uniform in size and shape. The ultrasonic action can make the bubbles aggregate together and reduce the bubble rise velocity, as well as prolong their time in the flotation process at the same time. It is beneficial to the sufficient collision and adhesion behavior between flotation bubbles and particles, eventually improving the efficiency of mineral flotation. Full article

(This article belongs to the Special Issue Separation and Extraction Technology in Mineral Processing)

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17 pages, 1092 KiB

Open AccessReview

Advances in Therapeutic Peptides Separation and Purification

by Othman Al Musaimi and Da’san M. M. Jaradat

Separations 2024, 11(8), 233; https://doi.org/10.3390/separations11080233 - 29 Jul 2024

Cited by 1 | Viewed by 2264

Abstract

Peptides are gaining prominence in various fields, including the pharmaceutical industry. To meet regulatory requirements, they must achieve a certain purity threshold to ensure safe administration. Numerous purification technologies have been employed to purify peptides, aiming to reduce cost and time while being [...] Read more.

Peptides are gaining prominence in various fields, including the pharmaceutical industry. To meet regulatory requirements, they must achieve a certain purity threshold to ensure safe administration. Numerous purification technologies have been employed to purify peptides, aiming to reduce cost and time while being sustainable and efficient. These include chromatography, magnetic nanoparticles, isoelectric focusing, and membrane filtration. The physicochemical properties of peptides are the main driving element behind these technologies. While chromatographic separation remains the gold standard for peptide separation and purification, with various models to predict the elution behaviors of peptides, other technologies have demonstrated their capability to meet the performance of established chromatographic methodologies, with better productivity and reduced cost. This opens the door for further investigational studies to assess these outcomes and potentially introduce new techniques for peptide purification. In this review, we examine these technologies in terms of their efficiency and their ability to meet sustainability requirements, concluding with remarks and an outlook on future advancements. Full article

(This article belongs to the Special Issue Peptide Synthesis, Separation and Purification)

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16 pages, 1182 KiB

Open AccessReview

Adsorption of Cobalt onto Zeolitic and Carbonaceous Materials: A Review

by Eduardo Díez, Rubén Miranda, Juan Manuel López, Arturo Jiménez, Naby Conte and Araceli Rodríguez

Separations 2024, 11(8), 232; https://doi.org/10.3390/separations11080232 - 27 Jul 2024

Viewed by 806

Abstract

At present, cobalt belongs to what are called critical raw materials due to its scarcity and its economic importance. Cobalt is a crucial element in the development of new technologies and applications for decarbonization, with around 40% of cobalt consumption being used for [...] Read more.

At present, cobalt belongs to what are called critical raw materials due to its scarcity and its economic importance. Cobalt is a crucial element in the development of new technologies and applications for decarbonization, with around 40% of cobalt consumption being used for rechargeable battery materials. Additionally, cobalt-based catalysts are used in the production of hydrogen fuel cells, and this element is also employed in the production of superalloys for aerospace and power generation industries. For this reason, it is imperative to increase cobalt recycling by recovering from secondary sources, such as decommissioned lithium-ion batteries. Among the technologies for cobalt recovery, adsorption is a reliable alternative as it allows its recovery even at low concentrations in aqueous solutions and is relatively low in cost. Among the potential adsorbents for cobalt recovery, this paper reviews two of the most promising adsorbents for cobalt recovery from aqueous solutions: zeolitic and carbonaceous materials. Regarding zeolitic materials, the maximum adsorption capacities are reached by FAU-type zeolites. In the case of carbonaceous materials, the actual trend is to obtain activated carbons from a wide range of carbon sources, including waste, the adsorption capacities, on average, being larger than the ones reached with zeolitic materials. Additionally, activated carbons allow, in many cases, the selective separation of cobalt from other ions which are present at the same time in the aqueous solutions such as lithium. Full article

(This article belongs to the Special Issue Development and Applications of Porous Materials in Adsorptions)

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14 pages, 5214 KiB

Open AccessArticle

Determination of Volatilome Profile in Carbonated Beverages Using n-Hexane as an Extractant by GC-MS

by Li Mu, Xianglong Meng, Huihong Luo, Qianqian Liu, Li Zhang, Xin Li, Ying Xu and Gang Li

Separations 2024, 11(8), 231; https://doi.org/10.3390/separations11080231 - 27 Jul 2024

Viewed by 1039

Abstract

A liquid–liquid extraction pretreatment method using n-hexane as the extractant was developed for the analysis of volatile aroma substances in three flavors (six cola samples, six lemon samples, and six orange samples) of carbonated beverages by gas chromatography–mass spectrometry (GC-MS). Quantitative analysis was [...] Read more.

A liquid–liquid extraction pretreatment method using n-hexane as the extractant was developed for the analysis of volatile aroma substances in three flavors (six cola samples, six lemon samples, and six orange samples) of carbonated beverages by gas chromatography–mass spectrometry (GC-MS). Quantitative analysis was conducted using the external standard method. The spiked recovery rate of α-terpineol was used as the evaluation criterion. Single-factor and response surface experiments were conducted to investigate the effects of extraction temperature, extraction time, and solvent-to-sample ratio. The results indicated that the maximum spiked recovery rate of α-terpineol, 81.00%, was achieved at an extraction temperature of 45 °C, extraction time of 30 min, and a solvent-to-sample ratio of 1 mL:15 mL. Thirty-four components were identified by GC-MS on the pretreated samples via the internal standard method. 1,4-Cineole, fenchyl alcohol, borneol, and α-terpineol are covered aroma substances in cola beverages. Two aromatic substances, D-limonene and α-terpineol, were detected in orange juices. α-Terpineol was detected in each lemon-flavor carbonated beverage sample. Going a step further, α-terpineol was detected in all 18 carbonated beverage samples and had high response values. The principal component analysis by functional group classification led to the conclusion that acids, phenols, hydrocarbons, alcohols, and ethers played a major contribution to the aroma of these 18 beverages. Increased separation of target compounds was found using the new pre-treatment methods, resulting in improved analytical resolution and selectivity. Full article

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17 pages, 5426 KiB

Open AccessArticle

An Empirical Study on the Upcycling of Glass Bottles into Hydrocyclone Separators

by Thomas Senfter, Thomas Neuner, Christian Bachmann, Manuel Berger, Christian Mayerl, Tobias Kofler, Michael Kraxner and Martin Pillei

Separations 2024, 11(8), 230; https://doi.org/10.3390/separations11080230 - 26 Jul 2024

Viewed by 669

Abstract

Cyclones are pivotal in mechanical process engineering and crucial in the complex field of separation technology. Their robustness and compact spatial requirements render them universally applicable and versatile across various industrial domains. Depending on the utilized fluid and field of application, both gas-based [...] Read more.

Cyclones are pivotal in mechanical process engineering and crucial in the complex field of separation technology. Their robustness and compact spatial requirements render them universally applicable and versatile across various industrial domains. Depending on the utilized fluid and field of application, both gas-based cyclones and hydrocyclones (HCs) are well established. Regarding HC design, enduring elongated flat cones have seen minimal alterations in shape and structure since their introduction over more than a hundred years ago. Experimental investigations regarding unconventional cone designs within scientific studies remain the exception. Therefore, this study focuses on alternative geometric configurations of the separation chambers and highlights their impact on separation and energy efficiency. To achieve this objective, different geometric shapes are investigated and retrofitted into HCs. The geometric foundation is derived from upcycled glass bottles. The repurposed bottles with a volume of 750 mL are used in conjunction with an inlet part, following the established Rietema design. Experimental tests are conducted with dilute phase separation, using 0.1–200 µm test particles in water. Comparisons between a bottle-based HC and a conventional Rietema design were conducted, establishing a benchmark against the standard. The findings revealed a noticeable correlation between separation efficiency and cone geometry. Conical designs demonstrated enhanced separation, particularly at lower volume flows. At the highest volume flow of 75 L min⁻¹, the best performing bottle cyclones showed separation efficiencies of 78.5%, 78.4% and 77.9% and therefore are in a competitive range with 78.0% efficiency, achieved using the commercial Rietema design. Minimal disparities in cut sizes were observed in terms of separation grade efficiency among the models tested. Variations in separation efficiency and fractional efficiency curves indicated nuanced differences in classification efficiency. Full article

(This article belongs to the Section Purification Technology)

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16 pages, 5889 KiB

Open AccessEditor’s ChoiceArticle

LC-MS/MS-QTOF Identification of Phenolic Compounds of Sideritis Species Cultivated in Greece

by Eleftheria H. Kaparakou, Charalabos D. Kanakis, Maroula G. Kokotou, Georgios Papadopoulos and Petros A. Tarantilis

Separations 2024, 11(8), 229; https://doi.org/10.3390/separations11080229 - 26 Jul 2024

Viewed by 1956

Abstract

Phenolic compounds are plant secondary metabolites, one of the most common and widespread groups of substances in plants, as well as a major group of phytochemicals present in medicinal and aromatic plants. The phytochemical composition of the hydroalcoholic extracts from S. raeseri, [...] Read more.

Phenolic compounds are plant secondary metabolites, one of the most common and widespread groups of substances in plants, as well as a major group of phytochemicals present in medicinal and aromatic plants. The phytochemical composition of the hydroalcoholic extracts from S. raeseri, S. scardica and S. syriaca was determined by LC-MS/MS-QTOF analysis. A total amount of 23 secondary metabolites were identified, including 17 flavonoids (Fs), 4 phenylethanoid glycosides (PEGs), 1 phenolic acid (PA) and 1 fatty acid (FA). Among the three species, the constituents that have been detected in all of nine samples were: verbascocide/isoverbascoside (PEG), apigenin 7-O- glucoside (F), isoscutellarein 7-O-[6″-O-acetyl]-allosyl(1→2)-glucoside (F) and apigenin 7-(4″-p-coumaroylglucoside) (F). This study contributes to the phytochemical characterization of the Sideritis spp. by providing a comparative study of bioactive compounds present in three different Sideritis species, S. raeseri, S. scardica and S. syriaca, which are widely used as a herbal medicine in Mediterranean region and Balkan Peninsula. Full article

(This article belongs to the Special Issue Isolation and Identification of Biologically Active Natural Compounds)

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12 pages, 2188 KiB

Open AccessArticle

Technology for Aiding the Cyanide Leaching of Gold Ores

by Jiahong Han, Shujuan Dai, Jiushuai Deng, Shandong Que and Yugao Zhou

Separations 2024, 11(8), 228; https://doi.org/10.3390/separations11080228 - 26 Jul 2024

Viewed by 1090

Abstract

Cyanide leaching technology was studied for low-grade oxidized gold ores in Guangxi Province. The gold grade of the raw ores was 1.32 g/t. The gold leaching rate was 90.91% under the optimal conditions for the following conventional leaching process: using steel forging as [...] Read more.

Cyanide leaching technology was studied for low-grade oxidized gold ores in Guangxi Province. The gold grade of the raw ores was 1.32 g/t. The gold leaching rate was 90.91% under the optimal conditions for the following conventional leaching process: using steel forging as the grinding medium, a grinding fineness of −0.074 mm accounting for 92.53%, a stirring speed of 1500 r/min, a pulp leaching concentration of 28.57%, a pH value of 10.5, a temperature of 25 °C, a leaching time of 24 h, and a potassium cyanide consumption of 4 kg/t. A new type of mixed aid-leaching agent (0.6 kg/t) was used, with a dosage of potassium cyanide of 2 kg/t. All else being equal, the gold leaching rate increased by 2.17% to 93.20% after 18 h of aid leaching compared to that of conventional leaching for 28 h. Meanwhile, the amount of potassium cyanide used was reduced by 50%. The aid-leaching agents restored the surface activity of passivated gold particles and depressed the adsorption of gold and its complexes by gangue minerals. This approach could shorten the leaching time and increase the gold leaching rate. Full article

(This article belongs to the Special Issue Separation Technology for Metals Recovery)

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16 pages, 3548 KiB

Open AccessArticle

Achieving Simultaneous Nitrification and Denitrification by a Membrane Aerated Biofilm Reactor at Moderate Lumen Pressure

by Huiyun Zhong, Yuanyuan Tang, Mengyu Wang and Liangfei Dong

Separations 2024, 11(8), 227; https://doi.org/10.3390/separations11080227 - 25 Jul 2024

Cited by 1 | Viewed by 723

Abstract

Lumen pressure is of crucial importance to achieve simultaneous nitrification and denitrification (SND) in the membrane aerated biofilm reactor (MABR); so, in this study, a laboratory-scale MABR was operated under different lumen pressures (7 kPa, 10 kPa, 13 kPa, and 16 kPa) successively [...] Read more.

Lumen pressure is of crucial importance to achieve simultaneous nitrification and denitrification (SND) in the membrane aerated biofilm reactor (MABR); so, in this study, a laboratory-scale MABR was operated under different lumen pressures (7 kPa, 10 kPa, 13 kPa, and 16 kPa) successively to verify its impact on nitrogen removal. The results showed that NH₄⁺-N oxidation was deficient under 7 kPa due to inadequate oxygen supply, while denitrification was depressed under 16 kPa. Total nitrogen removal efficiency was similar under 10 kPa and 13 kPa (around 78.9%), much higher than that under 7 kPa and 16 kPa (approximately 50%). The biomass density (22.35 g/m²) and biofilm thickness (500.3 µm) were the highest under 13 kPa, and EPS was increasingly secreted along with the increase in lumen pressure. The relative abundance of Nitrospirae was highest under 16 kPa (3.53%), indicating a higher lumen pressure could promote nitrifiers. The denitrifying-related microbes, such as β-proteobacteria, α-proteobacteria and ε-proteobacteria, showed an increasing and then decreasing pattern along with lumen pressure increase, and were enriched at 10 kPa. The results could draw the conclusion that SND could be achieved at moderate lumen pressure, i.e., 10 kPa and 13 kPa in this study. Full article

(This article belongs to the Special Issue Removal and Recovery of Nitrogen and Phosphorus from Wastewater)

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15 pages, 3963 KiB

Open AccessArticle

Characterization of Alginates of Sargassum from the Archipelago of Guadeloupe

by Naika Marcin, Valendy Thesnor, Valentin Duvauchelle, Alejandro Ponce-Mora, Lucia Gimeno-Mallench, Stacy Narayanin-Richenapin, Laura Brelle, Eloy Bejarano, Christelle Yacou, Muriel Sylvestre, Cristel Onésippe-Potiron, Patrick Meffre, Zohra Benfodda and Gerardo Cebrian-Torrejon

Separations 2024, 11(8), 226; https://doi.org/10.3390/separations11080226 - 25 Jul 2024

Cited by 1 | Viewed by 1347

Abstract

Sargassum is a genus of brown algae that causes a major impact to marine ecosystems. Although accumulation of this invasive seaweed is considered an environmental problem, Sargassum can also be resource of valuable molecules such as alginates. Alginates are polysaccharides extracted from the [...] Read more.

Sargassum is a genus of brown algae that causes a major impact to marine ecosystems. Although accumulation of this invasive seaweed is considered an environmental problem, Sargassum can also be resource of valuable molecules such as alginates. Alginates are polysaccharides extracted from the cell walls of brown seaweeds with multiple applications in food, cosmetics, pharmaceuticals, and biotechnology. In this study, we explored four different extraction protocols to isolate alginates from Sargassum from the archipelago of Guadeloupe. H-NMR, FTIR, and SEM were carried out to characterize isolated samples and describe their chemical and morphological properties. Antioxidant capacity of the isolated alginates was tested in the sample. FRAP assay showed free radical scavenging activity, and cell viability assay showed that alginates keep protective capacity against oxidative stress in cell cultures. In sum, the isolation methods used in this study are effective extractive methods to obtain alginates from Sargassum, which highlight this seaweed as a potential source of bioactive compounds that may be exploited for industrial and biomedical purposes. Full article

(This article belongs to the Section Analysis of Natural Products and Pharmaceuticals)

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17 pages, 5601 KiB

Open AccessArticle

A Comparison of Production Methods of High-Purity Perrhenic Acid from Secondary Resources

by Dorota Kopyto, Mateusz Ciszewski, Szymon Orda, Katarzyna Leszczyńska-Sejda, Joanna Malarz, Patrycja Kowalik, Karolina Pianowska, Karolina Goc, Grzegorz Benke, Alicja Grzybek, Dorota Babilas and Piotr Dydo

Separations 2024, 11(8), 225; https://doi.org/10.3390/separations11080225 - 24 Jul 2024

Viewed by 869

Abstract

Methods for obtaining high-purity perrhenic acid (with metallic impurities content below 100 ppm) of a high concentration > 200 g/dm³ and entirely from secondary raw materials were compared. Comparative analyses of three methods were performed: electrodialysis, solvent extraction (research carried out directly [...] Read more.

Methods for obtaining high-purity perrhenic acid (with metallic impurities content below 100 ppm) of a high concentration > 200 g/dm³ and entirely from secondary raw materials were compared. Comparative analyses of three methods were performed: electrodialysis, solvent extraction (research carried out directly as part of the Small Grant project acronym RenMet), and ion-exchange (developed as part of previous projects implemented by Łukasiewicz-IMN). The basic process parameters were selected as comparative indicators: efficiency and selectivity of the process, purity of the obtained product, availability and consumption of raw materials and reagents, equipment necessary to carry out the process, the profitability of the technology, and the ecological aspects, i.e., the possibility of managing the generated solid waste and post-production solutions. Analysis of the verified indicators allowed us to select the most economically and ecologically advantageous method of obtaining high-purity perrhenic acid from secondary raw materials. Its preparation using the ion-exchange method emphasizes the product’s purity and the process’s simplicity, using readily available waste materials and renewable ion-exchange resin, and is based on a sustainable circular economy. Full article

(This article belongs to the Special Issue Ion Exchange Mastery: Targeting Cationic and Anionic Species for Their Efficient Separations from Various Samples)

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9 pages, 1036 KiB

Open AccessArticle

Production of Perrhenic Acid by Solvent Extraction

by Karolina Pianowska, Grzegorz Benke, Karolina Goc, Joanna Malarz, Patrycja Kowalik, Katarzyna Leszczyńska-Sejda and Dorota Kopyto

Separations 2024, 11(8), 224; https://doi.org/10.3390/separations11080224 - 24 Jul 2024

Viewed by 800

Abstract

The aim of this work was to develop an effective method for obtaining perrhenic acid from available ammonia waste solutions using the solvent extraction method. An ammonia waste solution was used as the test material, with Re and NH₄⁺ concentrations of [...] Read more.

The aim of this work was to develop an effective method for obtaining perrhenic acid from available ammonia waste solutions using the solvent extraction method. An ammonia waste solution was used as the test material, with Re and NH₄⁺ concentrations of 13.5 and 43.7 g/dm³, respectively. The scope of this study includes the following: the selection of an appropriate extractant for testing, and the examination of the impact of individual parameters on the efficiency and selectivity of extraction and stripping. The obtained results made it possible to determine the conditions for the production of perrhenic acid via the extraction method using organic solutions of trihexyl(tetradecyl)phosphonium chloride (Cyphos IL 101). The outcome of this study was the development of a method for obtaining perrhenic acid and the production of the acid sample with an efficiency of >90% and a Re concentration of >100 g/dm³. Full article

(This article belongs to the Special Issue Separation Technology for Solid Waste Treatment and Recycling)

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10 pages, 1639 KiB

Open AccessArticle

Development of a Two-Dimensional Liquid Chromatography Online Deproteinization Method for Determining Paclitaxel-Related Substances in a Paclitaxel Injection (Albumin-Bound)

by Jing Yao, Xuejia Zhao, Yifei Jiang, Limin Zuo, Xiaodan Qiu, Xiaofang Lian, Huiyi Liu, Qingying Jia, Huimin Sun and Guangzhi Shan

Separations 2024, 11(8), 223; https://doi.org/10.3390/separations11080223 - 24 Jul 2024

Viewed by 738

Abstract

To determine the paclitaxel-related substances in a paclitaxel injection (albumin-bound), it is necessary to remove human blood albumin from the sample via solid-phase extraction and subsequently perform high-performance liquid chromatography analysis. The pre-processing operation is complicated, the duration of analysis is long, and [...] Read more.

To determine the paclitaxel-related substances in a paclitaxel injection (albumin-bound), it is necessary to remove human blood albumin from the sample via solid-phase extraction and subsequently perform high-performance liquid chromatography analysis. The pre-processing operation is complicated, the duration of analysis is long, and much human power and material resources are needed in the sample testing process. Thus, the purpose of this study was to develop a quick two-dimensional liquid chromatography method that requires less consumables and possesses high sensitivity. Samples were directly injected into one-dimensional solid-phase extraction columns to remove human blood albumin. Paclitaxel and its related substances in the solid-phase extraction columns were then eluted into two-dimensional analytical columns through valve switching technology. The sample pretreatment step can be omitted in this method, which allows for the analysis of paclitaxel and its related substances to be completed more quickly, within only 15 min, under the developed two-dimensional elution conditions. The established method had good linearity (R² = 0.9994), limit of detection (0.25 μg·mL⁻¹), limit of quantification (0.5 μg·mL⁻¹), precision (RSD = 0.5%), and accuracy (102.53–107.97%). Full article

(This article belongs to the Section Analysis of Natural Products and Pharmaceuticals)

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