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Volume 10
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Separations, Volume 10, Issue 5 (May 2023) – 50 articles

Cover Story (view full-size image): Marigold essential oil is a product of great industrial interest, due to its anti-inflammatory, antimicrobic, and wound healing properties. However, the development of a proper extraction technique is still an issue. In the present work, supercritical fluid extraction coupled with fractional separation was used to recover fragrance compounds from a marigold semi-finished material. In particular, the product of n-hexane extraction from marigold flowers (“concrete”) was utilized; this strategy represents a way to overcome the limitations of treating large volumes of vegetable material and seasonality constraints. Therefore, by changing the operating pressure and CO2 flow rate, extraction efficiency from marigold concrete was studied, and GC-MS analysis demonstrated that the fractionation between marigold essential oil and its waxes was successful. View this paper
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11 pages, 1603 KiB  
Article
Degradation of Azo Dye by Ultrasound in Rotating Flow Field
by Chunwei Shi, Fan Yang and Xiaogang Qu
Separations 2023, 10(5), 321; https://doi.org/10.3390/separations10050321 - 22 May 2023
Cited by 2 | Viewed by 1332
Abstract
Azo dyes such as Congo red can easily cause cancer when they come into contact or are absorbed by the human body, so it is urgent to find a fast and simple method for degrading Congo red. In order to better achieve this [...] Read more.
Azo dyes such as Congo red can easily cause cancer when they come into contact or are absorbed by the human body, so it is urgent to find a fast and simple method for degrading Congo red. In order to better achieve this research goal, an ultrasonic method was used to degrade Congo red solution in a rotating flow field. The concentration of hydroxyl radical in the solution was significantly increased under the action of ultrasonic cavitation, chemical action of zero valent iron, and mechanochemistry. Under the strong oxidation of hydroxyl radical and the reduction of nano zero valent iron peeled off in the reaction process, the reaction speed is significantly accelerated and should promote the reaction. The effect of increasing stirring and adding iron powder particles on ultrasonic cavitation was studied by numerical simulation, and the yield of hydroxyl radical in the system was measured by fluorescence analysis. The experimental results show that, first, the rotating field formed by mixing increases the uniformity of ultrasonic sound field distribution and the amplitude of sound pressure, and it improves the cavitation intensity. In the effective dispersion area, the strong ultrasonic wave can form a temporary high-energy microenvironment in the suspension through cavitation, generate high strength shockwaves and micro jets, and thus significantly deagglomerate the iron powder aggregates. The addition of iron powder particles then provides a complementary Fenton reagent for the degradation reaction. The concentration of hydroxyl radicals in the solution was significantly increased by the synergy of the two actions. The degradation rate of Congo red reached more than 99% after 30 min of reaction. Full article
(This article belongs to the Special Issue Efficient and Green Recovery of Metal Minerals)
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23 pages, 3085 KiB  
Article
Capillary Zone Electrophoresis with Light-Emitting Diode-Induced Fluorescence Detection for the Analysis of Monoclonal Antibodies: Detector Optimization through Design of Experiments and Comparison to UV Detection
by Holger Zagst, Sophie Hartung, Dina-Mareike Menges, Antonia Wittmann and Hermann Wätzig
Separations 2023, 10(5), 320; https://doi.org/10.3390/separations10050320 - 21 May 2023
Cited by 2 | Viewed by 1939
Abstract
Capillary zone electrophoresis (CZE) is an important technique for the analysis of monoclonal antibodies (mAbs). A recently released light-emitting diode (LED)-induced fluorescence (LEDIF) detector equipped with a 275 nm LED for the detection of proteins through their native fluorescence was used in this [...] Read more.
Capillary zone electrophoresis (CZE) is an important technique for the analysis of monoclonal antibodies (mAbs). A recently released light-emitting diode (LED)-induced fluorescence (LEDIF) detector equipped with a 275 nm LED for the detection of proteins through their native fluorescence was used in this study and compared to results obtained using the predominant detection mode, the measurement of the absorption of ultraviolet light (UV detection). This was accomplished using an established CZE method for the analysis of three mAbs: NISTmAb, matuzumab, and Intact Mass Check Standard (Waters). For this purpose, the detector’s settings were first optimized using a design of experiments approach. Three factors, rise time, photomultiplier high voltage supply, and acquisition frequency, were optimized by means of a D-optimal design. The optimal settings were then used for the investigation of signal-to-noise ratios (S/Ns), linearity, and precision. LEDIF detection offered a similar separation quality, up to 12 times higher S/Ns, and lower limits of detection compared to UV detection. Repeatability was excellent, with relative standard deviations (RSDs) of approximately 1% for percentage areas. For intermediate precision, RSDs of <2% (n = 3 × 10) were typically achieved. Overall, LEDIF detection was found to be an excellent and easily optimizable alternative to UV detection. Full article
(This article belongs to the Special Issue Early Career Stars in Separation Analysis of Natural Products and Pharmaceuticals)
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16 pages, 3110 KiB  
Article
Theoretical Study of a Closed-Cycle Evaporation System for Seawater Desalination
by Jun Liu, Yong Sun, Yizhu Zhang and Jiaquan Wang
Separations 2023, 10(5), 319; https://doi.org/10.3390/separations10050319 - 21 May 2023
Viewed by 1207
Abstract
This paper presents a numerical study of a closed-cycle evaporation system for the desalination of seawater. The system couples the condensing end of a heat pump with a humidifier, where the air is dehumidified in the heat pump evaporator. First, the mechanism of [...] Read more.
This paper presents a numerical study of a closed-cycle evaporation system for the desalination of seawater. The system couples the condensing end of a heat pump with a humidifier, where the air is dehumidified in the heat pump evaporator. First, the mechanism of action of the closed-cycle evaporation system was analyzed from the perspective of heat transfer, and the control equations for the heat and mass transfer of the system were investigated. In addition, a mathematical model of the system was developed and validated. The influence of several important parameters of the air and seawater entering the system on the system’s performance under the design conditions was investigated numerically. The parametric analysis showed that the effect of the seawater mass flow rate on the system’s productivity was not significant. As the air mass flow rate increases, the freshwater production rate increases and then decreases. The output ratio (GOR) of the system was estimated and found to be competitive with other reported HDH systems. Full article
(This article belongs to the Special Issue Separation Techniques in Sustainable Water Management)
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14 pages, 1999 KiB  
Article
Application of Quality by Design Approach in the Optimization and Development of the UPLC Analytical Method for Determination of Fusidic Acid in Pharmaceutical Products
by Mohamed Ibrahim, Nasser Ali Alhabib, Doaa Alshora, Mounir M. Salem Bekhit, Ehab Taha, Wael A. Mahdi and Abdulelah M. Harthi
Separations 2023, 10(5), 318; https://doi.org/10.3390/separations10050318 - 19 May 2023
Cited by 6 | Viewed by 1623
Abstract
Background: Analytical techniques are a crucial method used in quality control procedures. Fusidic acid (FU), an antibacterial drug, is available on the market in a semisolid dosage form. This work aimed to develop a simple, sensitive, and robust UPLC assay for FU. Method: [...] Read more.
Background: Analytical techniques are a crucial method used in quality control procedures. Fusidic acid (FU), an antibacterial drug, is available on the market in a semisolid dosage form. This work aimed to develop a simple, sensitive, and robust UPLC assay for FU. Method: The effect of the formic acid concentration (X1 (1%, 0.55%, and 0.1%)), and column temperature (X2 (40, 32.5, and 25 °C)) on the retention time, peak area, and peak height were determined. Results: The results show that a long retention time of 1.18 min can be achieved with a low column temperature and a low to medium concentration of formic acid. A good peak height resolution was obtained with a low concentration of formic acid at different temperature settings. The optimized condition was suggested by the software program to analyze the drug in a mobile phase, consisting of 72% acetonitrile and 28% water containing 0.1% formic acid with a column temperature adjusted to 40 °C. Conclusion: The method was validated in terms of linearity, accuracy, precision, and robustness. In addition, the stability degradation study determined that the method can separate the drug from other degradation production. The method was applicable to determine the drug content in the marketed product. Full article
(This article belongs to the Special Issue Sensitivity Enhancement Approaches to the Separation Techniques for Pharmaceutical Analysis and Therapeutic Drug Monitoring)
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17 pages, 1526 KiB  
Review
Rare Earth Tungstate: One Competitive Proton Conducting Material Used for Hydrogen Separation: A Review
by Hongda Cheng
Separations 2023, 10(5), 317; https://doi.org/10.3390/separations10050317 - 19 May 2023
Cited by 3 | Viewed by 1465
Abstract
Membrane technology is an advanced hydrogen separation method that is of great significance in achieving hydrogen economy. Rare earth tungstate membranes have both high hydrogen permeability and remarkable mechanical/chemical stability, exhibiting good application prospects in hydrogen separation. This review provides the basic aspects [...] Read more.
Membrane technology is an advanced hydrogen separation method that is of great significance in achieving hydrogen economy. Rare earth tungstate membranes have both high hydrogen permeability and remarkable mechanical/chemical stability, exhibiting good application prospects in hydrogen separation. This review provides the basic aspects and research progress on rare earth tungstate hydrogen separation membranes. The crystal structure, proton transport properties, and membrane stability under a chemical atmosphere are introduced. Different membrane construction designs, such as single-phase, dual-phase, and asymmetric rare earth tungstate membranes, are summarized. Lastly, the existing problems and development suggestions for tungstate membranes are discussed. Full article
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15 pages, 5910 KiB  
Article
Sunlight-Driven Degradation of Alprazolam and Amitriptyline by Application of Binary Zinc Oxide and Tin Oxide Powders
by Nina Finčur, Daniela Šojić Merkulov, Predrag Putnik, Vesna Despotović, Nemanja Banić, Szabolcs Bognár, Dušica Jovanović, Sanja Panić, Tamara Ivetić and Biljana Abramović
Separations 2023, 10(5), 316; https://doi.org/10.3390/separations10050316 - 19 May 2023
Cited by 5 | Viewed by 1614
Abstract
In recent years, much attention has been paid to pharmaceuticals as potential toxic bioactive substances in the worldwide environment. These compounds are continuously introduced into the surroundings in small concentrations, which certainly affects the quality of water, ecosystem, and the general health of [...] Read more.
In recent years, much attention has been paid to pharmaceuticals as potential toxic bioactive substances in the worldwide environment. These compounds are continuously introduced into the surroundings in small concentrations, which certainly affects the quality of water, ecosystem, and the general health of living organisms. Photocatalysis is a promising technique for treating pharmaceutically active compounds as organic pollutants over traditional technologies. This study proposes the application of photocatalysts composed of zinc oxide (ZnO) and tin oxide (SnO2), synthesized using a solid-state method, for the photocatalytic degradation of two selected psychoactive drugs, amitriptyline (AMI) and alprazolam (ALP), under simulated solar and UV irradiation in an aqueous system. The newly synthesized photocatalysts were characterized using the following techniques: SEM/EDS, XRD, DLS, and UV/Vis spectroscopy. The obtained data confirmed the successful synthesis and the possible photocatalytic application of the new materials. Concerning the photocatalytic evaluation, the main results indicate that the highest removal efficiency of AMI and ALP was reached in the presence of ZnO/SnO2 synthesized in a molar ratio of 2:1 and calcined at 700 °C, under 1.0 mg/mL catalyst loading. Based on the reutilization findings, it can be concluded that the mentioned photocatalyst had not lost its efficiency after three successive runs for the photodegradation of ALP. Additionally, pure ZnO powders showed the highest activity after calcination at 500 °C, in the case of both examined pollutants. The experiments with tert-butanol, sodium fluoride, and ethylenediaminetetraacetic acid suggested that the relative contribution of various reactive species changed in the following order: positively charged holes > OHfree• > OHads•. Full article
(This article belongs to the Section Environmental Separations)
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6 pages, 220 KiB  
Editorial
Food Quality and Safety: Advances in Analytical Methods and Applications
by Angela Sorbo, Claudia Zoani and Daniele Passeri
Separations 2023, 10(5), 315; https://doi.org/10.3390/separations10050315 - 18 May 2023
Cited by 1 | Viewed by 1898
Abstract
The Special Issue “Food Quality and Safety: Advances in Analytical Methods and Applications” was open to expert reviews and original contributions dealing with advances in analytical methods for the detection and quantification of potentially hazardous substances in food matrices [...] Full article
(This article belongs to the Special Issue Food Quality and Safety: Advances in Analytical Methods and Applications)
15 pages, 2695 KiB  
Protocol
An Optimised MS-Based Versatile Untargeted Metabolomics Protocol
by Cátia F. Marques and Gonçalo C. Justino
Separations 2023, 10(5), 314; https://doi.org/10.3390/separations10050314 - 18 May 2023
Cited by 2 | Viewed by 4042
Abstract
Untargeted metabolomics approaches require complex samples containing the endogenous metabolites of a biological system. Here, we describe a set of protocols that can be applied to various types of samples, including prokaryotic and eukaryotic cells, as well as animal and human samples. Following [...] Read more.
Untargeted metabolomics approaches require complex samples containing the endogenous metabolites of a biological system. Here, we describe a set of protocols that can be applied to various types of samples, including prokaryotic and eukaryotic cells, as well as animal and human samples. Following a single extraction step, samples are analysed using different chromatographic conditions coupled to high-resolution mass spectrometry. Quantification of metabolite changes between samples is performed without internal standards, using peak areas from extracted ion chromatograms for statistical analysis. Bioinformatics annotation of the results allows a pathway- and process-oriented analysis across biological sample conditions, allowing a complete pathway interrogation. Full article
(This article belongs to the Section Analysis of Natural Products and Pharmaceuticals)
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15 pages, 1801 KiB  
Article
Resin Adsorption of Phenolic Compounds from Olive Leaf and Coffee Residue Extracts: Batch and Packed Column Adsorption Experimental Investigation and Mathematical Modeling
by Michael P. Kodjapashis, Andreas D. Zentelis, Dimitris P. Zagklis, Varvara Sygouni and Christakis A. Paraskeva
Separations 2023, 10(5), 313; https://doi.org/10.3390/separations10050313 - 17 May 2023
Cited by 3 | Viewed by 2082
Abstract
Phenolic compounds are important secondary metabolites often found in nature, and most prominently in plants. Plant biomass residues can be a sustainable source of this high-added-value group of compounds that can be used in the food and cosmetics industries due to their antioxidant [...] Read more.
Phenolic compounds are important secondary metabolites often found in nature, and most prominently in plants. Plant biomass residues can be a sustainable source of this high-added-value group of compounds that can be used in the food and cosmetics industries due to their antioxidant properties. Olea europaea is a widely studied source of phenolic compounds, with olive leaves being an untapped solid residue with high phenolic content. Coffee residues after coffee extraction is another biomass residue stream rich in phenols. In this work, phenolic extracts of these two substrates, alongside different fractions produced through ultrafiltration and nanofiltration, were examined in resin adsorption experiments. Amberlite XAD16N was used as adsorbent in both batch and packed column experiments, with the experimental results being fitted with mathematical models for batch kinetics, adsorption isotherms, and column adsorption. The tested adsorbent proved capable of separating the target compounds, exhibiting a capacity of 72 mg of olive leaf phenols from nanofiltration retentate per g of resin in batch adsorption experiments, second order kinetics better described the batch adsorption process, while the use of the Thomas model sufficiently described the continuous adsorption process in packed columns (R2 > 0.9). Full article
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11 pages, 1685 KiB  
Article
Distributions of OCPs and CUPs in the Sediment and Surface Water Close to a Drinking Water Reservoir in Northeastern China
by Yingying Yu and Jialong Chi
Separations 2023, 10(5), 312; https://doi.org/10.3390/separations10050312 - 16 May 2023
Viewed by 1231
Abstract
In the Chinese city of Wuchang, Heilongjiang Province, a survey was conducted to track the concentrations and distributions of several organic pollutants near drinking water reservoirs, such as conventional organochlorine pesticides (OCPs) and currently in use pesticides (CUPs), including organophosphorus pesticides (OPPs) and [...] Read more.
In the Chinese city of Wuchang, Heilongjiang Province, a survey was conducted to track the concentrations and distributions of several organic pollutants near drinking water reservoirs, such as conventional organochlorine pesticides (OCPs) and currently in use pesticides (CUPs), including organophosphorus pesticides (OPPs) and neutral herbicides (NHs). From October 2007 to July 2008, a total of 32 pairs of water and sediment samples were gathered and examined. The results showed that the total concentrations of OCPs, OPPs, and NHs in the sediments were 0.42–7.8 ng/dm3 below the detection limit of these pollutants in sediments. The total concentration of OPPs in the water varied from the LoD to 180 ng/dm3 while NHs were 6.3 to 740 ng/dm3. While the CUP concentrations changed significantly throughout the year, the OCP concentrations were less impacted by seasonal fluctuations, indicating no recent introduction of these chemicals. The use of pesticides on crops in the primarily agricultural area was the main factor contributing to higher concentrations of CUPs during the summer. Full article
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11 pages, 959 KiB  
Article
Diallyldimethylammonium Chloride (DADMAC) in Water Treated with Poly-Diallyldimethylammonium Chloride (PDADMAC) by Reversed-Phase Ion-Pair Chromatography—Electrospray Ionization Mass Spectrometry
by Francesca Di Gaudio, Salvatore Barreca and Santino Orecchio
Separations 2023, 10(5), 311; https://doi.org/10.3390/separations10050311 - 15 May 2023
Cited by 4 | Viewed by 3330
Abstract
Poly-diallyldimethylammonium (PDADMAC) chloride is a flocculant agent extensively used in water clarification treatments. Commercial polyelectrolyte formulations often contain residual monomer (DADMAC), reaction by-products and other reactants as contaminants that could potentially affect human health. In the present study, we optimized an analytical method [...] Read more.
Poly-diallyldimethylammonium (PDADMAC) chloride is a flocculant agent extensively used in water clarification treatments. Commercial polyelectrolyte formulations often contain residual monomer (DADMAC), reaction by-products and other reactants as contaminants that could potentially affect human health. In the present study, we optimized an analytical method based on reversed-phase ion-pair chromatography coupled with mass spectrometry for quantifying ultra-trace levels of DADMAC, without preliminary treatments, in drinking water distributed by the Palermo aqueduct. The method was validated in terms of accuracy (recovery between 80 to 120%), precision (RSD < 10%), linearity range (from 0.5 to 15 µg/L), limit of quantification and limit of detection (LOQ 0.42 µg/L and LOD 0.12 µg/L). DADMAC was detected in all analysed water samples and the concentration ranged from 1.2 to 3.8 µg/L whit a mean value of 1.7 µg/L. To the best of our knowledge, this paper represents the first study concerning DADMAC concentration in water samples collected in Italy and, in this context, this paper can be considered very interesting when comparing future data on DADMAC monitoring in water. Moreover, this is one of a few cases where DADMAC was found in drinking water. Full article
(This article belongs to the Section Chromatographic Separations)
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20 pages, 3820 KiB  
Article
Removal of Sr(II) in Aqueous Solutions Using Magnetic Crayfish Shell Biochar
by Wenchao Lu, Jundong Feng, Marta Otero, Tao Liao and Liang Qiu
Separations 2023, 10(5), 310; https://doi.org/10.3390/separations10050310 - 13 May 2023
Cited by 2 | Viewed by 1662
Abstract
The cooling water of nuclear power plants and discarded crayfish shells (CS), both containing Sr(II), are waste resources that cause environmental pollution and endanger human health. In this study, magnetic biochar produced by crayfish shells (mag@CSBC) was used as an adsorbent to remove [...] Read more.
The cooling water of nuclear power plants and discarded crayfish shells (CS), both containing Sr(II), are waste resources that cause environmental pollution and endanger human health. In this study, magnetic biochar produced by crayfish shells (mag@CSBC) was used as an adsorbent to remove radionuclide Sr(II) in an aqueous solution and under irradiation conditions. Scanning electron microscopy, X-ray diffraction analysis, Fourier-transform infrared spectroscopy and vibration sample magnetometer analysis were used to characterize mag@CSBC. In addition, an isothermal adsorption experiment conducted under irradiation conditions determined that the maximum adsorption capacity of mag@CSBC was 21.902 mg/g, which was 1.896 mg/g higher than that from experiments conducted under conditions without irradiation and more suitable for the Freundlich isotherm model. The kinetic experiment proved that irradiation could improve the adsorption cap acity of mag@CSBC and reduce the adsorption equilibrium time. At the same time, the experiment further proved that, under irradiated conditions, the adsorption rate of mag@CSBC can reach more than 90%, and the adsorption capacity is the highest when the pH is 8 and the reaction process is exothermic. Competitive adsorption with Na(I) has a high selectivity and strong recyclability. Finally, the mechanism of Sr(II) adsorption by mag@CSBC under irradiation was studied. In conclusion, mag@CSBC, as a low-cost, easy-to-synthesize, environmentally friendly and easy-to-recycle adsorbent, can be applied in batches for the removal of Sr(II) in aqueous solutions. In particular, the concept of using irradiation technology to optimize adsorption behavior serves as an inspiration for future research. Full article
(This article belongs to the Special Issue Advanced Methods for Separation and Extraction of Radionuclides)
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17 pages, 4647 KiB  
Article
Bifunctional Adsorbents Based on Jarosites for Removal of Inorganic Micropollutants from Water
by Arely Monserrat López-Martínez, Sasirot Khamkure and Prócoro Gamero-Melo
Separations 2023, 10(5), 309; https://doi.org/10.3390/separations10050309 - 13 May 2023
Cited by 3 | Viewed by 1368
Abstract
This paper presents a novel family of jarosites with the molecular formula MFe3(SO4)2(OH)6·xH2O; M = Na, K, NH4 that have high efficiency in the adsorption of As(V) and Pb(II) dissolved in water. [...] Read more.
This paper presents a novel family of jarosites with the molecular formula MFe3(SO4)2(OH)6·xH2O; M = Na, K, NH4 that have high efficiency in the adsorption of As(V) and Pb(II) dissolved in water. The jarosites have been prepared by conventional heating at temperatures close to 95 °C for 3 h. The synthesis method was improved and optimized to reduce the time and energy consumption. The improved conventional heating method allowed for the synthesis of Na− and K−jarosites with a yield of up to 97.8 wt.% at 105 and 150 °C, respectively, in 3 h. The Na−, K−, and NH4−jarosites were synthesized at 150 °C in 5 min via a microwave-assisted method, which yielded jarosite crystalline agglomerates with more uniform topography, shape, and size than the conventional method. Both methods allowed the selective synthesis of jarosites. Chemical decomposition of jarosites suspended in water occurred at a pH less than 2 and higher than 10 and temperatures up to 150 °C. In the solid state, the jarosites were thermally stable at least to 300 °C. The Na−jarosite presented a maximum adsorption capacity (Qmax) of 65.6 mg g−1 for As(V) and 94 mg g−1 for Pb(II). The jarosites are considered promising bifunctional adsorbents for the remediation of contaminated water due to their improved synthesis method, stability, and high adsorption capacity for ions of different natures. Full article
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13 pages, 1563 KiB  
Article
HPLC-DAD Development and Validation Method for Short-Chain Fatty Acids Quantification from Chicken Feces by Solid-Phase Extraction
by Lenin Rodolfo Díaz-Corona, Karina Jeanette Parra-Saavedra, Renata Sofia Mora-Alonzo, María Esther Macías-Rodríguez, Alma H. Martínez-Preciado, Santiago José Guevara-Martínez, Adalberto Zamudio-Ojeda and Adriana Macaria Macias-Lamas
Separations 2023, 10(5), 308; https://doi.org/10.3390/separations10050308 - 13 May 2023
Cited by 3 | Viewed by 3475
Abstract
A solid-phase extraction (SPE) process, followed by an HPLC-DAD method, was developed and validated to quantify short-chain fatty acids (SCFAs) and applied to analyze chicken feces samples. This study aimed to report the use of the STRATATM-X-A 96 Well Plate SPE [...] Read more.
A solid-phase extraction (SPE) process, followed by an HPLC-DAD method, was developed and validated to quantify short-chain fatty acids (SCFAs) and applied to analyze chicken feces samples. This study aimed to report the use of the STRATATM-X-A 96 Well Plate SPE cartridge method as the first step in quantifying SCFAs. A stationary reverse-phase Luna Omega C18 column kept at 40 °C was used, with a gradient elution mobile phase (H2SO4 and Acetonitrile, 98:2), a flow rate of 1.2 mL/min, and detection at 210 nm. A mixture of acetic, propionic, and butyric acid was used as thestandard. The method showed a linear relationship, with a coefficient of determination of R2 = 0.9987, R2 = 0.9985, and R2 = 0.9966 for acetic, propionic, and butyric acid, respectively. Concerning sensitivity, an LOD and LOQ of 0.14, 0.14, 0.14 mg/mL and 0.44, 0.45, 0.43 mg/mL were obtained for acetic, propionic, and butyric acid, respectively. According to the sample analysis, the accuracy was 76.05, 95.60, and 81.56% for acetic, propionic, and butyric acid, respectively. The developed method is simple, fast, linear, sensitive, accurate, precise, and robust for the quantification of SCFAs. This could serve as an alternative to conventional methodologies for the determination of these critical components in the intestinal health of chicken feces. Full article
(This article belongs to the Special Issue HPLC: A Key Tool for Analytical Chemistry)
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11 pages, 559 KiB  
Article
Categorization of Marijuana Suspected Policies’ Seizures in Southeast Serbia According to Cannabinoids Content
by Emilija Kostic, Mirjana Djukic, Aleksandra Antovic, Miodrag Zdravkovic, Miroslav Milic, Ivan Stojanovic, Stevan Todorovic and Maja Vujovic
Separations 2023, 10(5), 307; https://doi.org/10.3390/separations10050307 - 12 May 2023
Viewed by 1949
Abstract
Background: The cannabis plant or marijuana has been used since ancient times for different purposes. An increase in the content of THC in cannabis has been observed worldwide, whereas the CBD content is dropping. This study’s main goal was to categorize marijuana suspected [...] Read more.
Background: The cannabis plant or marijuana has been used since ancient times for different purposes. An increase in the content of THC in cannabis has been observed worldwide, whereas the CBD content is dropping. This study’s main goal was to categorize marijuana suspected policies’ seizures (MSPS) based on the cannabinoid component concentrations concerning their potency and age. Methods: The samples were MSPS seized in southeast Serbia from April 2019 to April 2020. The cannabinoid content was determined using gas chromatography with mass spectrometry. Descriptive statistics were performed using Linux LibreOffice Calc. Results: All of the samples had a THC content higher than 0.3%, thus classifying the samples as marijuana according to the Serbian Law on Psychoactive Controlled Substances. The highest concentration of THC was 16.10%, while the lowest was 4.90%. The highest average concentration of THC (12.39%) was found in the buds. Only 11.81% of the samples had a CBD concentration higher than 1%, making all other marijuana samples extremely psychoactive. Most of the samples were older than 2 years, according to the calculated CBN/THC ratio. Conclusion: Our results confirm trends regarding the dominance of THC content in contemporary cannabis worldwide. It is necessary to monitor trends of cannabis potency in Serbia continuously because of its location. Full article
(This article belongs to the Special Issue Separation Technology in the Analysis of Biogenic Volatile Organic Compounds)
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15 pages, 3677 KiB  
Protocol
Isolation of Peroxisomes from Frozen Liver of Rat by Differential and Iodixanol Gradient Centrifugation
by Lina Baz, Mona Al-thepyani, Salha Algarni and Hana Gashlan
Separations 2023, 10(5), 306; https://doi.org/10.3390/separations10050306 - 12 May 2023
Viewed by 2472
Abstract
In the last decade, research has shown that most diseases are associated with organelle dysfunction in which metabolites play a crucial role or indicate specific processes. Peroxisomes are cellular organelles attracting an increasing amount of attention and are now recognized as essential players [...] Read more.
In the last decade, research has shown that most diseases are associated with organelle dysfunction in which metabolites play a crucial role or indicate specific processes. Peroxisomes are cellular organelles attracting an increasing amount of attention and are now recognized as essential players in physiological conditions and diseases. However, a limited amount of research focuses on isolating the organelles and studying their properties and the diseases resulting from organelle dysfunction. All methods for isolating peroxisomes are based on fresh tissue samples. To the best of our knowledge, this is the first work in which peroxisomes have been isolated from frozen rat liver. In our work, we isolated peroxisomes from frozen rat liver at −80 °C and evaluated the separation success and degree of purification of isolated peroxisomes by measuring the relative specific activity, purification fold, and percentage yield (Y%) of organelle marker enzymes in the isolated fractions. The percentage of protein distribution and density was also estimated. Our results showed that the purified peroxisome fraction (F3-peroxisome) had significantly higher relative specific activity, as well as the highest purification fold and percentage yield of catalase compared with the enzyme markers of other organelles in the postnuclear supernatant (PNS), postmitochondrial supernatant (PMS), and light mitochondria–peroxisome (LM-P) fractions. In addition, the percentage of protein distribution was significantly lower in the F3-peroxisome fraction compared with PNS, PMS, and LM-P fractions while the percentage of protein distribution and density of the F3-peroxisome fraction after iodixanol centrifugation were significantly higher than those of the F1 and F2 fractions. The present work demonstrates the possibility of isolating peroxisomes from frozen liver samples efficiently, which could pave the way for further research in the future on other subcellular organelles from frozen samples. Full article
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18 pages, 3817 KiB  
Article
Separation of Co(II) and Ni(II) Using an Analog of Glycine-Betaine Based on Task-Specific Ionic Liquids
by Lamia Boulafrouh, Stéphanie Boudesocque, Aminou Mohamadou and Laurent Dupont
Separations 2023, 10(5), 305; https://doi.org/10.3390/separations10050305 - 11 May 2023
Cited by 1 | Viewed by 1675
Abstract
A series of salts based on ethyl ester glycine-betaine derivatives, viz tri(n-pentyl)[2-ethoxy-2-oxoethyl]ammonium bromide, have been synthesized. These cations generate hydrophobic ionic liquids (ILs) with bis(trifluoromethylsulfonyl)imide (Tf2N−) or dicyanamide (Dca−) anions. These new analogues of glycine-betaine-based [...] Read more.
A series of salts based on ethyl ester glycine-betaine derivatives, viz tri(n-pentyl)[2-ethoxy-2-oxoethyl]ammonium bromide, have been synthesized. These cations generate hydrophobic ionic liquids (ILs) with bis(trifluoromethylsulfonyl)imide (Tf2N−) or dicyanamide (Dca−) anions. These new analogues of glycine-betaine-based ionic liquids (AGB-ILs) were characterized using spectroscopic methods (IR, 1H, and 13C NMR) and elemental analysis. These AGB-ILs were used for the selective separation of Ni(II) and Co(II) in saline media using pure ILs phase or ILs diluted in organic solvent. Interestingly, extraction of Co(II) and Ni(II) in Dca-based AGB-ILs can be enhanced using salts with chaotropic anions such as NaNO3 (E > 90% for Co(II) and E = 85% for Ni(II)). Tf2N−-based ionic liquids do not extract Ni(II) or Co(II) even in NaCl 4M. Dca−-based ILs lead to a quasi-quantitative extraction of Co(II), while extraction of Ni(II) is limited to a few percent (17%) leading to separation factors higher than 100, ensuring a good separation of both metals. Cobalt could be back-extracted from the ionic liquid phase with water or with an aqueous solution of Na2SO4, which limits the release of the AGB cation in aqueous media, thus preserving its integrity. Results obtained by AGB-ILs diluted in organic solvent were comparable to those obtained with the pure AGB-ILs phase, indicating that this strategy can be deployed on systems working continuously out of equilibrium since the extraction mechanisms involve fast equilibria. Full article
(This article belongs to the Special Issue Recent Advances in Separation and Recovery of Metals)
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12 pages, 5986 KiB  
Article
Microporous Carbons Obtained via Solvent-Free Mechanochemical Processing, Carbonization and Activation with Potassium Citrate and Zinc Chloride for CO2 Adsorption
by Amonrada Saning, Rabindra Dubadi, Laemthong Chuenchom, Decha Dechtrirat and Mietek Jaroniec
Separations 2023, 10(5), 304; https://doi.org/10.3390/separations10050304 - 10 May 2023
Cited by 5 | Viewed by 2262
Abstract
In this study, the facile and sustainable synthesis of highly microporous carbons is explored to reduce the extensive use of harsh activating agents and solvents. The role of potassium citrate (PC) as a greener activating agent in addition to the conventional ZnCl2 [...] Read more.
In this study, the facile and sustainable synthesis of highly microporous carbons is explored to reduce the extensive use of harsh activating agents and solvents. The role of potassium citrate (PC) as a greener activating agent in addition to the conventional ZnCl2 is investigated in the mechanochemical solvent-free preparation of highly microporous carbon materials from chestnut tannin (CT), a biomass-type carbon precursor. A small amount of potassium citrate as a chemical activator coupled with CO2 activation at 700 °C afforded carbons with higher specific surface area (1256 m2 g−1) and larger micropore volume (0.54 cm3 g−1) as compared to the carbons activated with both PC and ZnCl2. The high microporosity of the PC-activated carbon materials, significantly enlarged after CO2 activation from micropore volume of 0.16 to 0.54 cm3 g−1, makes them favorable for CO2 adsorption, as evidenced by high adsorption capacity of 3.55 mmol g−1 at ambient conditions (25 °C, 1 bar). This study shows that the solvent-free mechanochemical processing of tannin in the presence of PC is a promising method for obtaining highly microporous carbon materials. Full article
(This article belongs to the Special Issue Applications of Porous Materials in Adsorption)
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3 pages, 171 KiB  
Editorial
Modeling, Simulation, and Optimization of Membrane Processes
by Mingheng Li
Separations 2023, 10(5), 303; https://doi.org/10.3390/separations10050303 - 10 May 2023
Viewed by 1866
Abstract
From water desalination and gas purification to metal recovery and beyond, membrane separation has become integral to numerous industrial applications [...] Full article
(This article belongs to the Special Issue Modeling, Simulation, and Optimization of Membrane Processes)
14 pages, 2178 KiB  
Article
Development of a Fast and Sensitive UPLC–MS/MS Analytical Methodology for Fenebrutinib Estimation in Human Liver Microsomes: In Vitro and In Silico Metabolic Stability Evaluation
by Mohamed W. Attwa, Aishah M. Alsibaee, Haya I. Aljohar, Ali S. Abdelhameed and Adnan A. Kadi
Separations 2023, 10(5), 302; https://doi.org/10.3390/separations10050302 - 9 May 2023
Cited by 7 | Viewed by 1592
Abstract
Fenebrutinib (GDC-0853; FNB) is an oral small molecule that was developed by Roche Pharmaceuticals to slow multiple sclerosis progression. FNB is a reversible bruton tyrosine kinase (BTK) inhibitor, which showed the maximum potency of BTK inhibitors in phase III clinical trials for multiple [...] Read more.
Fenebrutinib (GDC-0853; FNB) is an oral small molecule that was developed by Roche Pharmaceuticals to slow multiple sclerosis progression. FNB is a reversible bruton tyrosine kinase (BTK) inhibitor, which showed the maximum potency of BTK inhibitors in phase III clinical trials for multiple sclerosis. In the current study, a fast, specific, and sensitive UPLC-MS/MS method for FNB quantification in human liver microsomes (HLMs) was established with application to the evaluation of metabolic stability. The UPLC-MS/MS methodology was verified using the stated USFDA validation guidelines for bioanalytical methodologies that involve selectivity, linearity, accuracy and precision, carryover and extraction recovery, stability, and matrix effect. The FNB calibration curve displayed a linearity in the range from 1 ng/mL to 3000 ng/mL (y = 1.731x + 2.013; R2: 0.9954; RSD < 4.37%) in the HLMs matrix. The limit of quantification was 0.88 ng/mL, which verified the UPLC-MS/MS analytical method sensitivity. The intraday and interday precision and accuracy results of the developed UPLC-MS/MS method were −3.99–14.0% and 0.52–3.83%, respectively. FNB and savolitinib (SVB) (internal standard) were chromatographically separated utilizing an isocratic mobile phase system with a ZORBAX Eclipse plus-C18 (50 mm, 2.1 mm, and 1.8 μm) column. The metabolic stability parameters for FNB, involving high intrinsic clearance (58.21 mL/min/kg) and a short in vitro half-life (13.93 min), revealed the high extraction ratio of FNB. Reviewing the literature revealed that the current UPLC-MS/MS method is the first analytical method for FNB quantification in the HLMs matrix with application to the assessment of FNB metabolic stability. Full article
(This article belongs to the Special Issue Application of Microextraction and Chromatography in Bioanalysis and Pharmaceutical Analysis)
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14 pages, 868 KiB  
Article
Swietenia mahagoni Leaves Extract: Antifungal, Insecticidal, and Phytochemical Analysis
by Wael M. Khamis, Ahmed A. Heflish, Sarah El-Messeiry, Said I. Behiry, Abdulaziz A. Al-Askar, Yiming Su, Ahmed Abdelkhalek and Mohamed K. Gaber
Separations 2023, 10(5), 301; https://doi.org/10.3390/separations10050301 - 9 May 2023
Cited by 7 | Viewed by 3098
Abstract
In this study, we investigated the antifungal properties of an acetone extract derived from the leaves of Swietenia mahagoni (SMAL) against two isolated fungi, Fusarium equiseti (OQ820153) and Rhizoctonia solani (OQ820152), from rice sheath. The extract was effective in inhibiting the growth of [...] Read more.
In this study, we investigated the antifungal properties of an acetone extract derived from the leaves of Swietenia mahagoni (SMAL) against two isolated fungi, Fusarium equiseti (OQ820153) and Rhizoctonia solani (OQ820152), from rice sheath. The extract was effective in inhibiting the growth of both fungi at the highest concentration tested, 3000 μg·mL−1. Laboratory tests on the LC20 of SMAL extract (49.86 mg·L−1) versus pyriproxyfen 10% EC (1.96 mg·L−1) were accomplished on Aphis gossypii Glover. The extract potently reduced the survival of the nymphs (49.58%) more than the other treatments. The longevity of nymphs treated with the extract had the highest prolongation at 9.67 days. The olfactory choice test exhibited the lowest aphid attraction percentage (23.33%). The HPLC of SMAL extract contained various phenolic compounds, and the most abundant found were catechin (752.64 µg·g−1), gallic acid, and chlorogenic acid, as well as flavonoids such as rutin (585.24 µg·g−1) and naringenin. A GC–MS analysis revealed n-hexadecanoic acid (37.1%) as the major compound, followed by oleic acid. These results suggest that SMAL extract has the potential to help plants fight against fungal and insect infections, making it a promising natural and renewable solution for long-term plant pest regulation. Full article
(This article belongs to the Special Issue Natural Plants as Source of Bioactive Compounds: Isolation, Identification and Biological Activity)
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32 pages, 3494 KiB  
Review
Recent Advances in Using Adsorbent Derived from Agricultural Waste for Antibiotics and Non-Steroidal Anti-Inflammatory Wastewater Treatment: A Review
by Abu Hassan Nordin, Abdul Samad Norfarhana, Siti Fadilla Md Noor, Syafikah Huda Paiman, Muhammad Luqman Nordin, Siti Muhamad Nur Husna, Rushdan Ahmad Ilyas, Norzita Ngadi, Aznizam Abu Bakar, Zuliahani Ahmad, Mohammad Saifulddin Azami, Wan Izhan Nawawi and Walid Nabgan
Separations 2023, 10(5), 300; https://doi.org/10.3390/separations10050300 - 8 May 2023
Cited by 11 | Viewed by 3834
Abstract
Antibiotics and non-steroidal anti-inflammatory drugs (NSAIDs) are among the top pharmaceutical contaminants that have been often found in the aquatic environment. The presence of these contaminants in the aquatic environment is of great concern since it has a negative impact on both ecology [...] Read more.
Antibiotics and non-steroidal anti-inflammatory drugs (NSAIDs) are among the top pharmaceutical contaminants that have been often found in the aquatic environment. The presence of these contaminants in the aquatic environment is of great concern since it has a negative impact on both ecology and human health. In contrast to other tertiary treatments, adsorption stands out as a viable treatment approach since it provides benefits such as easier operating conditions with no byproduct formation. Commercial activated carbon is widely researched as a pharmaceutical adsorbent, but its large-scale applicability is constrained by its high cost. Agricultural waste also contains a large amount of various functional groups, which may be adapted to surface modification to increase its adsorption ability. In this regard, this study is designed to review the recent progress of efficient adsorbents derived from various agricultural wastes for the removal of antibiotics and NSAIDs contaminants from water bodies. Adsorbents made from agricultural waste have important benefits over commercial activated carbon for the reduction in waste while controlling water pollution. Full article
(This article belongs to the Special Issue Removal of Metals or Other Toxic Substances from Wastewaters by Natural Sorbents)
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13 pages, 4522 KiB  
Article
Separation of Zinc from Zinc Ferrite by Magnetization Roasting and Ammonia Leaching
by Zeqiang Xie, Tao Jiang, Yufeng Guo, Shuai Wang, Feng Chen, Lingzhi Yang and Ganghua Fu
Separations 2023, 10(5), 299; https://doi.org/10.3390/separations10050299 - 8 May 2023
Cited by 2 | Viewed by 1479
Abstract
Zinc ferrite can be found in zinc-bearing dust in ironmaking and steelmaking. It is difficult to be recovered due to its stable properties. The magnetization roasting and ammonia leaching method were used to separate iron and zinc from zinc ferrite in this study. [...] Read more.
Zinc ferrite can be found in zinc-bearing dust in ironmaking and steelmaking. It is difficult to be recovered due to its stable properties. The magnetization roasting and ammonia leaching method were used to separate iron and zinc from zinc ferrite in this study. Thermodynamic analysis showed that the key to the selective reduction of zinc ferrite to zinc oxide and ferric oxide is to control the appropriate temperature and atmosphere. The influences of the selective reduction roasting process of zinc ferrite on the conversion rate, phase change, and microevolution behavior were investigated. The microstructure analysis showed that the distribution area of iron was mainly gray, and the distribution area of zinc was mainly white grid lines. The zinc content in the white area was higher than that in the gray area. With the increase in temperature and PCO, the white area expanded and the migration of zinc and iron was accelerated, but the iron in the white area still existed. The ammonia leaching of the magnetization-roasted product showed that a zinc leaching rate of 78.12% was achieved under the following conditions: the roasting atmosphere of PCO/P(CO+CO2) = 25%, the roasting temperature of 750 °C, roasting duration for 45 min, n(NH3-H2O):n(NH4Cl) = 1:1, the solid–liquid ratio of 40 g/L, leachate concentration of 6 mol/L, leaching duration of 90 min, the leaching temperature of 50 °C, and the stirring rate of 200 rpm. Full article
(This article belongs to the Special Issue Advanced Methods for Recovery of Valuable Metals from Waste)
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12 pages, 2505 KiB  
Article
Fractionation of Marigold Waxy Extract Using Supercritical CO2
by Alessandra Zanotti, Lucia Baldino, Mariarosa Scognamiglio and Ernesto Reverchon
Separations 2023, 10(5), 298; https://doi.org/10.3390/separations10050298 - 8 May 2023
Viewed by 2143
Abstract
Marigold oil is a product of great industrial interest thanks to its wide range of medicinal and wound-healing properties. In this work, supercritical carbon dioxide was used to recover marigold essential oil from the hexane solvent extract of marigold flowers, the floral “concrete”. [...] Read more.
Marigold oil is a product of great industrial interest thanks to its wide range of medicinal and wound-healing properties. In this work, supercritical carbon dioxide was used to recover marigold essential oil from the hexane solvent extract of marigold flowers, the floral “concrete”. This starting material was mixed with synthetic paraffinic waxes to heighten its melting point and viscosity, thus, improving material processability. Supercritical fluid extraction and fractionation of the modified marigold “concrete” was carried out, and the effect of pressure and CO2 mass flow rate was studied. The pressure was varied from 80 to 180 bar, keeping the temperature constant at 40 °C: the higher the pressure, the larger the CO2 solvent power and extraction yield (up to 9.40% w/w). Nevertheless, the optimum between productivity and process selectivity was found at 100 bar. By changing the CO2 mass flow rate (from 1.20 to 1.50 kg/h), we noted that mass transfer resistance was located externally. GC-MS analysis showed that the most abundant compounds in the oil were δ-cadinene (25%), γ-cadinene (16%), τ-muurolol (6.5%), and α-muurolene (6%). Moreover, the traces of oil and waxes showed no mutual contamination between lighter species and waxes, meaning that the fractionation step was successful. Full article
(This article belongs to the Special Issue Essential Oils: Extraction, Chemical Composition, and Biological Activity)
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19 pages, 8233 KiB  
Article
Particulate Matter Detachment from a Magnetizable Single Fiber Applying Magnetic Forces in Ambient Air
by Julia Szabadi, Jörg Meyer and Achim Dittler
Separations 2023, 10(5), 297; https://doi.org/10.3390/separations10050297 - 7 May 2023
Cited by 2 | Viewed by 1575
Abstract
The potential utilization of magnetic effects in gas particle separation is a current subject of research. This paper demonstrates for the first time that a single magnetizable filter fiber can be deflected by a magnetically induced excitation for a selected combination of parameters, [...] Read more.
The potential utilization of magnetic effects in gas particle separation is a current subject of research. This paper demonstrates for the first time that a single magnetizable filter fiber can be deflected by a magnetically induced excitation for a selected combination of parameters, resulting in the removal of deposited particle structures with high detachment levels. A correlation between the magnetic flux density and achieved acceleration to overcome the adhesive forces/strength of the particle structure was determined. The degree of detachment after each regeneration was calculated by comparing the projection area before and after detachment using high-speed images. At a magnetic flux density of B = 38.5 mT, accelerations of maximum a = 105 m·s−2 are achieved, depending on the axial position along the single fiber. The degrees of regeneration achieved at these parameters depend on the amount of fiber loading and on the fiber orientation in the gravitational field. The horizontal orientation of the fiber leads to an increased reattachment of precedingly detached particle structures after deflection compared to a vertical orientation. High particle loading on the fiber results in enhanced detachment by inertia. Under the most favorable process conditions investigated, detachment levels of >90% are achieved. Full article
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15 pages, 4390 KiB  
Article
Biomass Zilla spinosa Fruit Functionnalized Polyethyleneimine Polymer: Analysis and Application for the Elimination of Calmagite in Water
by Mahjoub Jabli, Arwa Elaissi and Afnan Altwala
Separations 2023, 10(5), 296; https://doi.org/10.3390/separations10050296 - 6 May 2023
Cited by 3 | Viewed by 1400
Abstract
The valorization of natural polymeric substrates has increased due to their uses and applications in several fields. The existence of many functional groups in their chemical structures allows them to be easily subjected to chemical modifications. This work focuses on the exploration of [...] Read more.
The valorization of natural polymeric substrates has increased due to their uses and applications in several fields. The existence of many functional groups in their chemical structures allows them to be easily subjected to chemical modifications. This work focuses on the exploration of a new low-cost and abundant cellulosic biomass, Zilla spinosa fruit. The biomaterial was functionnalized with polyethyleneimine (1%, 3%, 5%, and 8%) in order to impart new reactive sites on its surface. The virgin and functionnalized biomaterials were analysed using several analytical methods; X-ray Photoelectron Spectroscopy (XPS), Fourier Transform Infrared (FT-IR), Scanning Electron Microscopy (SEM), and Thermogravimetric analysis (TGA). XPS spectrum of Zilla spinosa-polyethyleneimine exhibited the appearance of a new peak at 399 eV, which corresponds to N1s (5.07%). The adsorption characteristics of the prepared adsorbents were evaluated toward calmagite, an azoic and anionic dye. The adsorption capacity of Zilla spinosa-polyethyleneimine (5%) reached 114 mg/g at pH = 5, T = 20 °C, and time = 60 min conditions; though, it does not exceed 8.4 mg/g for the virgin Zilla spinosa under the same experimental conditions. The kinetic data followed both pseudo-first-order and pseudo-second-order kinetic equations suggesting a physicochemical process. The adsorption mechanism was found to be exothermic and non-spontaneous. Overall, Zilla spinosa-polyethyleneimine has demonstrated a high adsorption level which could be considered a promising candidate to remove synthetic dye molecules from contaminated water. Full article
(This article belongs to the Special Issue Research on Adsorption and Purification Technology of Water and Air Pollution)
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17 pages, 5135 KiB  
Article
Development and Validation of Analytical Method Using Gas Chromatography with Triple Quadrupole Mass Spectrometry for the Detection of Alkyl Halides as Potential Genotoxic Impurities in Posaconazole
by Hari Naga Prasada Reddy Chittireddy, J. V. Shanmukha Kumar, Anuradha Bhimireddy, Mohammed Rafi Shaik, Mujeeb Khan, Merajuddin Khan, Tae Hwan Oh and Baji Shaik
Separations 2023, 10(5), 295; https://doi.org/10.3390/separations10050295 - 6 May 2023
Viewed by 2333
Abstract
Effective risk management and control methods for potentially genotoxic impurities (PGIs), including alkyl halides, are of significant importance in the medicinal (pharmaceutical) sector. The three alkyl halides in posaconazole are PGIs. The detection and assessment of genotoxic substances is a top priority for [...] Read more.
Effective risk management and control methods for potentially genotoxic impurities (PGIs), including alkyl halides, are of significant importance in the medicinal (pharmaceutical) sector. The three alkyl halides in posaconazole are PGIs. The detection and assessment of genotoxic substances is a top priority for all regulatory organizations. Quantifying PGIs at trace levels using standard analytical techniques, such as gas chromatography (GC) and high-performance liquid chromatography (HPLC), is challenging for the pharmaceutical manufacturing industry. Thus, the detection of trace quantities of PGIs in posaconazole is essential for developing sensitive analytical methodologies. The objective of this study was to establish an analytical technique for quantifying the three PGIs (alkyl halides) in posaconazole and its intermediate. These alkyl halides are 1-(2,4-difluorophenyl) ethan-1-one (PGI-1), (Z)-1-(1-bromoprop-1-en-2-yl)- 2,4-difluorobenzene (PGI-2), and 1-bromo-2-(2,4-difluorophenyl) propan-2-ol (PGI-3). To identify trace quantities (parts per million (ppm)) of these impurities, we employed a gas chromatography (GC-MS/MS) equipped with a triple quadrupole mass spectrometry detector. The GC column was a USP phase G43, which is a mid-polar 6% cyanopropyl; 94% polydimethylsiloxane, with a 60 m length, 0.32 mm inner diameter, and 1.8 μm film thickness. Helium (He) was used as the carrier gas, with a flow rate of 1.5 mL/min. A thermal gradient elution program was used for this procedure. The method was calibrated for the three PGIs with limits of detection (LOD) and quantification (LOQ) of 0.01 and 0.025 ppm, respectively. The linear range of concentrations (25–150%) was maintained with respect to the specification level. This method was validated according to the ICH regulations and was shown to be specific, rugged, robust, precise, sensitive, accurate, linear, and stable. Therefore, in this newly developed method, the combination of suitable analytical techniques, such as GC-MS/MS and proper chromatographic conditions and column selection with the lowest LOD and LOQ, have allowed the induction of excellent ionization. These conditions have successfully facilitated the identification of PGI-1, PGI-2, and PGI-3 in posaconazole and its intermediate during routine analysis. Full article
(This article belongs to the Special Issue Comprehensive Separations of Complex Mixtures by Gas Chromatography/Mass Spectrometry)
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17 pages, 4528 KiB  
Article
Study on Homogeneous Reduction Technology in Gas Samples for Oil and Gas Loss
by Lu Fan, Yu Yue, Honglin Song, Xiaohan Zhang, Xinyun Hu and Yongshou Dai
Separations 2023, 10(5), 294; https://doi.org/10.3390/separations10050294 - 5 May 2023
Viewed by 1518
Abstract
The process of storing oil depots and combined station tanks is affected by factors such as process technology, equipment, and management methods. Inevitably, some heavy hydrocarbon components will condense. According to the available literature, the existing detection methods are not enough to accurately [...] Read more.
The process of storing oil depots and combined station tanks is affected by factors such as process technology, equipment, and management methods. Inevitably, some heavy hydrocarbon components will condense. According to the available literature, the existing detection methods are not enough to accurately measure the component composition so that the proportion of heavy hydrocarbon substances in the lost gas is reduced. In this paper, by inventing a homogeneous reduction device, the lost gas in the entire laboratory process was kept in a homogeneous state so that the gas components were well-retained. Using the homogeneous reduction method and a traditional inspection method, gas chromatography was performed on a standard gas and the on-site lost gas, respectively. The standard gas measurement results show that the mean deviations of the homogeneous reduction method and the traditional test method were −3.45% and −11.62%, respectively, and the reduction degree reached 96.55% with the homogeneous reduction method. The results of the on-site gas loss measurements show that the proportions of most hydrocarbon substances in each lost gas increase to varying degrees after using the homogeneous reduction technology. Therefore, it is proved that these components can be better preserved using the homogeneous reduction method. It can effectively avoid the condensation of components, which is of great significance to the study of oil and gas loss. Full article
(This article belongs to the Topic Oil, Gas and Water Separation Research)
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15 pages, 1535 KiB  
Article
Sex Differentiation from Human Scent Chemical Analysis
by Petra Pojmanová, Nikola Ladislavová, Veronika Škeříková, Jaromír Kukal and Štěpán Urban
Separations 2023, 10(5), 293; https://doi.org/10.3390/separations10050293 - 5 May 2023
Cited by 1 | Viewed by 1934
Abstract
Human scent traces are often the only pieces of evidence providing information about individuals that were present at a crime scene. In this study, the possibility of sex differentiation using detailed chemical analyses of human scent samples for forensic purposes is discussed. The [...] Read more.
Human scent traces are often the only pieces of evidence providing information about individuals that were present at a crime scene. In this study, the possibility of sex differentiation using detailed chemical analyses of human scent samples for forensic purposes is discussed. The human scent samples were analyzed through the use of headspace-gas chromatography/mass spectrometry (HS-GC/MS). The results of these chemical analyses were evaluated using several data processing approaches (Linear Support Vector Machine, Quadratic Discriminant Analysis, and Ridge Regression), which were applied to distinguish between sexes from the human scent samples obtained from the palms of six volunteers for twelve weeks. This study indicates that sex differentiation based on the chemical analysis of human scent samples using HS-GC/MS is possible. The best results were obtained using the Ridge Regression with thresholding providing accuracy and a critical sensitivity of the sex differentiation of better than 91%. Full article
(This article belongs to the Special Issue Chemical Separations in Criminalistics)
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11 pages, 1015 KiB  
Article
Simultaneous Quantification of Some Fluoroquinolone Residues in Real Wastewater Effluents Using CZE
by Sherif A. Abdel-Gawad and Ali Altharawi
Separations 2023, 10(5), 292; https://doi.org/10.3390/separations10050292 - 5 May 2023
Cited by 6 | Viewed by 1435
Abstract
Since active pharmaceutical ingredients (APIs) are directly related to human health, monitoring and quantifying them in the environment is a crucial and challenging issue. Using capillary-zone electrophoresis (CZE), four frequently used fluoroquinolones (FQs), ciprofloxacin, sparfloxacin, moxifloxacin, and gatifloxacin, were efficiently isolated and measured [...] Read more.
Since active pharmaceutical ingredients (APIs) are directly related to human health, monitoring and quantifying them in the environment is a crucial and challenging issue. Using capillary-zone electrophoresis (CZE), four frequently used fluoroquinolones (FQs), ciprofloxacin, sparfloxacin, moxifloxacin, and gatifloxacin, were efficiently isolated and measured in pharmaceutical industrial wastewater. Solid-phase extraction (SPE) was developed and used as an efficient sample pretreatment procedure. The capillary electrophoretic procedure’s various parameters were tuned to produce the optimal separation pattern for the drugs under consideration. All of the drugs under study were quantified in a concentration range of 0.5 to 50 µg/mL. After full assay validation in compliance with ICH-Q2B criteria, real wastewater samples were subjected to effective SPE, and the proposed assay was successfully used to determine the examined FQs in real wastewater samples. Full article
(This article belongs to the Section Environmental Separations)
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