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Showing 601 - 735 of 735 Journals sorted alphabetically
Scientific Reports     Open Access   (Followers: 85)
Sensors and Actuators B: Chemical     Hybrid Journal   (Followers: 18)
Sensors and Actuators Reports     Open Access   (Followers: 6)
Separation & Purification Reviews     Hybrid Journal   (Followers: 7)
Separation Science and Technology     Hybrid Journal   (Followers: 12)
Separations     Open Access   (Followers: 5)
Silicon Chemistry     Hybrid Journal   (Followers: 1)
Small Methods     Hybrid Journal   (Followers: 1)
Small Science     Open Access  
Small Structures     Hybrid Journal   (Followers: 1)
Smart Materials Research     Open Access   (Followers: 7)
SmartMat     Open Access  
Soft     Open Access  
Soft Nanoscience Letters     Open Access   (Followers: 1)
Solar RRL     Hybrid Journal  
Solid State Communications     Hybrid Journal   (Followers: 7)
Solid State Nuclear Magnetic Resonance     Hybrid Journal   (Followers: 3)
Solid State Sciences     Hybrid Journal   (Followers: 9)
Solvent Extraction and Ion Exchange     Hybrid Journal   (Followers: 7)
SPE Polymers     Open Access  
Spectral Analysis Review     Open Access  
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy     Hybrid Journal   (Followers: 15)
Spectrochimica Acta Part B: Atomic Spectroscopy     Hybrid Journal   (Followers: 17)
Spectroscopy and Spectral Analysis     Full-text available via subscription   (Followers: 1)
Starch / Staerke     Hybrid Journal   (Followers: 3)
Steel Research International     Hybrid Journal   (Followers: 22)
Structural Chemistry     Hybrid Journal   (Followers: 1)
Substantia     Open Access  
Supramolecular Chemistry     Hybrid Journal   (Followers: 5)
Supramolecular Materials     Full-text available via subscription   (Followers: 5)
Surface and Coatings Technology     Hybrid Journal   (Followers: 32)
Surface Science     Hybrid Journal   (Followers: 21)
Surface Science Reports     Full-text available via subscription   (Followers: 13)
Surfaces     Open Access   (Followers: 2)
Surfaces and Interfaces     Hybrid Journal   (Followers: 1)
Sustainable Chemical Processes     Open Access   (Followers: 3)
Sustainable Chemistry and Pharmacy     Full-text available via subscription   (Followers: 1)
Synfacts     Hybrid Journal   (Followers: 5)
Synlett     Hybrid Journal   (Followers: 44)
Synthesis     Hybrid Journal   (Followers: 53)
Talanta     Hybrid Journal   (Followers: 10)
Talanta Open     Full-text available via subscription   (Followers: 5)
TecnologĂ­a QuĂ­mica     Open Access  
Telematics and Informatics Reports     Full-text available via subscription   (Followers: 4)
Tenside Surfactants Detergents     Full-text available via subscription   (Followers: 2)
Tetrahedron     Hybrid Journal   (Followers: 77)
Tetrahedron Chem     Full-text available via subscription   (Followers: 6)
Tetrahedron Letters     Hybrid Journal   (Followers: 81)
The Alkaloids: Chemistry and Biology     Full-text available via subscription   (Followers: 1)
The All Results Journals : Chem     Open Access  
The Canadian Journal of Chemical Engineering     Hybrid Journal   (Followers: 5)
The Enzymes     Full-text available via subscription   (Followers: 2)
The Protein Journal     Hybrid Journal   (Followers: 5)
Theoretical and Experimental Chemistry     Hybrid Journal  
Theoretical Chemistry Accounts     Hybrid Journal   (Followers: 6)
Thermochimica Acta     Hybrid Journal   (Followers: 18)
Tip Revista Especializada en Ciencias Quimico-Biologicas     Open Access  
Topics in Current Chemistry     Hybrid Journal  
Toxicology International     Full-text available via subscription   (Followers: 5)
Toxicology Research     Partially Free   (Followers: 8)
Transition Metal Chemistry     Hybrid Journal   (Followers: 6)
Trends in Chemistry     Hybrid Journal  
Turkish Computational and Theoretical Chemistry     Open Access  
Ultrasonics Sonochemistry     Hybrid Journal   (Followers: 2)
Universal Journal of Chemistry     Open Access   (Followers: 1)
Vietnam Journal of Chemistry     Hybrid Journal  
Western Undergraduate Research Journal : Health and Natural Sciences     Open Access  
Wiley Interdisciplinary Reviews : Computational Molecular Science     Hybrid Journal   (Followers: 4)
World Journal of Chemical Education     Open Access   (Followers: 2)
X-Ray Spectrometry     Hybrid Journal   (Followers: 4)

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Number of Followers: 5  

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ISSN (Online) 2297-8739
Published by MDPI Homepage  [84 journals]
  • Separations, Vol. 9, Pages 156: Green Assessment of Chromatographic
           Methods Used for the Analysis of Four Methamphetamine Combinations with
           Commonly Abused Drugs

    • Authors: Saif A. Alharthy, Muath A. Alharthi, Sultan A. Almalki, Sattam H. Alosaimi, Abdullah H. Aqeel, Sultan A. Altowairqi, Izzeddin Alsalahat, Dibya Sundar Panda, Mona Y. Alsheikh, Ibrahim A. Naguib
      First page: 156
      Abstract: Numerous agents with anxiolytic or stimulant effects have the potential to be overused, and their misuse is associated with serious side effects. In Saudi Arabia, the estimated percentage of Saudis who abuse drugs is around 7–8% and the age range is 12–22 years. Methamphetamine, captagon, tramadol, heroin, and cannabis/cannabinoids have been proven to be the most commonly abused drugs in Saudi Arabia, with methamphetamine being at the top of the list. The present study focuses on the chromatographic analytical methods used for the analysis of methamphetamine in combination with commonly abused drugs, aiming to point out the greenest among them. These mixtures have been chosen as they are analyzed periodically and frequently in criminal evidence and forensic medicine. Therefore, the chances of hazards for analysts and the environment are high if the mixtures are not handled appropriately. This study aims to compare 23 chromatographic methods used for the analysis of methamphetamine mixtures in four major combinations, and to assess their greenness by using three greenness assessment tools, namely, NEMI, ESA and AGREE, to recommend the greenest analytical method. The NEMI results were proven to have low discriminating abilities and, accordingly, the comparisons are based on ESA and AGREE scores. The analysis results show that the safest methods with the most eco-friendly results (based on ESA and AGREE) are the GC-MS method proposed by Mohammed et al. to analyze methamphetamine and captagon mixtures (ESA = 79 and AGREE = 0.57), the UHPLC–MS-MS method proposed by Busardò et al. to analyze methamphetamine and cannabis/cannabinoid mixtures (ESA = 78 and AGREE = 0.57), the LC-MS method proposed by Herrin et al. to analyze methamphetamine and tramadol mixtures (ESA = 81 and AGREE = 0.56), and the LC-MS method proposed by Postigo-et al to analyze methamphetamine and heroin mixtures (ESA = 76 and AGREE = 0.58).
      Citation: Separations
      PubDate: 2022-06-22
      DOI: 10.3390/separations9070156
      Issue No: Vol. 9, No. 7 (2022)
  • Separations, Vol. 9, Pages 157: Enantioseparation of syn- and
           anti-3,5-Disubstituted Hydantoins by HPLC and SFC on Immobilized
           Polysaccharides-Based Chiral Stationary Phases

    • Authors: Mladenka Jurin, Darko Kontrec, Tonko Dražić, Marin Roje
      First page: 157
      Abstract: The enantioseparation of syn- and anti-3,5-disubstituted hydantoins 5a–i was investigated on three immobilized polysaccharide-based columns (CHIRAL ART Amylose-SA, CHIRAL ART Cellulose-SB, CHIRAL ART Cellulose-SC) by high performance liquid chromatography (HPLC) using n-hexane/2-PrOH (90/10, v/v) or 100% dimethyl carbonate (DMC) as mobile phases, respectively, and by supercritical fluid chromatography (SFC) using CO2/alcohol (MeOH, EtOH, 2-PrOH; 80/20, v/v) as a mobile phase. The chromatographic parameters, such as separation and resolution factors, have indicated that Amylose-SA is more suitable for enantioseparation of the most analyzed syn- and anti-3,5-disubstituted hydantoins than Celullose-SB and Cellulose-SC in both HPLC and SFC modalities. All three tested columns showed better enantiorecognition ability toward anti-hydantoins compared to syn-hydantoins, both in HPLC and SFC modes. We have demonstrated that environmentally friendly solvent DMC can be efficiently used as the mobile phase in HPLC mode for enantioseparation of hydantoins on the immobilized polysaccharide-based chiral stationary phases.
      Citation: Separations
      PubDate: 2022-06-22
      DOI: 10.3390/separations9070157
      Issue No: Vol. 9, No. 7 (2022)
  • Separations, Vol. 9, Pages 158: Validation of an Analytical Method for the
           Determination of Manganese and Lead in Human Hair and Nails Using Graphite
           Furnace Atomic Absorption Spectrometry

    • Authors: José Ricardo Forero-Mendieta, Juan David Varón-Calderón, Diana Angelica Varela-Martínez, Diego Alejandro Riaño-Herrera, Rubén Darío Acosta-Velásquez, John Alexander Benavides-Piracón
      First page: 158
      Abstract: This article describes the validation of analytical methods for the determination of Manganese (Mn) and lead (Pb) by graphite furnace atomic absorption spectrometry (GFAAS) in human hair and nail samples. Method validation parameters such as linearity, repeatability, reproducibility, and precision were determined. In addition, the limit of detection (LOD), the limit of quantification (LOQ), and measurement uncertainty were calculated. The developed method was linear in the concentration ranges of 0.001–0.015 and 0.002–0.020 µg·L−1 of Mn and Pb, respectively. The determination coefficients obtained were greater than 0.995. The recoveries obtained after the addition of the standard concentration for the metals ranged from 84.80–107.98%, with a precision not exceeding 12.97% relative standard deviation. The calculated LOD and LOQ for Mn and Pb are within the ranges established by Commission Regulation (EU) No. 836/2011. The expanded uncertainty was estimated to be less than 9.93–6.59% for Mn and Pb. Matrix effects were also studied, finding a smooth effect in both matrices. The analysis of 30 samples of each type revealed the presence of Mn in 30 and Pb in 13 samples. Overall, the proposed validation method was considered optimal for the determination of Mn and Pb.
      Citation: Separations
      PubDate: 2022-06-23
      DOI: 10.3390/separations9070158
      Issue No: Vol. 9, No. 7 (2022)
  • Separations, Vol. 9, Pages 159: Chemical Fingerprinting Profile and
           Targeted Quantitative Analysis of Phenolic Compounds from Rooibos Tea
           (Aspalathus linearis) and Dietary Supplements Using UHPLC-PDA-MS

    • Authors: Omer I. Fantoukh, Yan-Hong Wang, Abidah Parveen, Mohammed F. Hawwal, Zulfiqar Ali, Gadah A. Al-Hamoud, Amar G. Chittiboyina, Elizabeth Joubert, Alvaro Viljoen, Ikhlas A. Khan
      First page: 159
      Abstract: Aspalathus linearis (Burm.f.) R. Dahlgren, commonly known as rooibos tea, was consumed traditionally by the indigenous South African inhabitants as an herbal remedy. Beside antioxidant properties, it displays antiallergic, antispasmodic, and hypoglycemic activities. An ultra-high-performance liquid chromatography method coupled with photodiode array and mass spectrometry detectors were developed for the determination of 14 phenolic constituents from leaves and stems of A. linearis. The efficient separation was performed within 30 min at a temperature of 30 °C by using C-18 column as the stationary phase and water/acetonitrile with 0.05% formic acid as the mobile phase. Method validation for linearity, repeatability, limits of detection, and limits of quantification was achieved. The limits of detection from 0.2–1 μg/mL were reported for the standard compounds. Their total content varied substantially (1.50–9.85 mg/100 mg sample) in 21 dietary supplements. The presence of regioisomers and diastereomers which co-elute on a variety of stationary phases make separation for quantification purposes challenging. This method was found to be efficient in providing low retention times and excellent resolution for this type of phytochemicals. The established method is suitable for chemical fingerprint analysis of A. linearis and cost-effective for quality control of rooibos tea products.
      Citation: Separations
      PubDate: 2022-06-23
      DOI: 10.3390/separations9070159
      Issue No: Vol. 9, No. 7 (2022)
  • Separations, Vol. 9, Pages 160: Accurate Flow Regime Classification and
           Void Fraction Measurement in Two-Phase Flowmeters Using Frequency-Domain
           Feature Extraction and Neural Networks

    • Authors: Siavash Hosseini, Abdullah M. Iliyasu, Thangarajah Akilan, Ahmed S. Salama, Ehsan Eftekhari-Zadeh, Kaoru Hirota
      First page: 160
      Abstract: Two-phase flow is very important in many areas of science, engineering, and industry. Two-phase flow comprising gas and liquid phases is a common occurrence in oil and gas related industries. This study considers three flow regimes, including homogeneous, annular, and stratified regimes ranging from 5–90% of void fractions simulated via the Mont Carlo N-Particle (MCNP) Code. In the proposed model, two NaI detectors were used for recording the emitted photons of a cesium 137 source that pass through the pipe. Following that, fast Fourier transform (FFT), which aims to transfer recorded signals to frequency domain, was adopted. By analyzing signals in the frequency domain, it is possible to extract some hidden features that are not visible in the time domain analysis. Four distinctive features of registered signals, including average value, the amplitude of dominant frequency, standard deviation (STD), and skewness were extracted. These features were compared to each other to determine the best feature that can offer the best separation. Furthermore, artificial neural network (ANN) was utilized to increase the efficiency of two-phase flowmeters. Additionally, two multi-layer perceptron (MLP) neural networks were adopted for classifying the considered regimes and estimating the volumetric percentages. Applying the proposed model, the outlined flow regimes were accurately classified, resulting in volumetric percentages with a low root mean square error (RMSE) of 1.1%.
      Citation: Separations
      PubDate: 2022-06-24
      DOI: 10.3390/separations9070160
      Issue No: Vol. 9, No. 7 (2022)
  • Separations, Vol. 9, Pages 161: The Preparation of the Essential Oil from
           Pomelo (Citrus maxima ‘Shatian Yu’) Peel Using
           Microwave-Assisted Distillation by Pectinase Soaking and Its Anti-Fungal

    • Authors: Xiaonan Zhang, Yan Huang, Yaqian Niu, Zhiwei Liu, Mengyu Chen, Yimin An, Lubin Zhang
      First page: 161
      Abstract: To verify the anti-fungus properties of the crop-harmful pseudocercospora, the essential oil (EO) of pomelo peel (PP) was extracted by a single factor combined with response surface optimization. Meanwhile, the composition and activity of EO were studied. The PP was squeezed by a screw extruder and pretreatmented by pectinase, then extracted by microwave-assisted steam distillation. The optimal conditions were as follows: pectinase dosage was 69.17 μmol/g, microwave power was 651.42 W and extraction time was 43.84 min. The dry weight (DW) yield of PPEO reached 14.63 mL/kg DW after BBD optimization. There were 23 compounds in the PPEO identified by GC-MS. Limonene, α-phrenbutene, and laurene in PPEO accounted for 79.31%, 4.72%, and 3.46%, respectively. In addition, the antifungal was effective when the concentration of PPEO was 3.5 mg/mL. Therefore, this study has guiding significance for the development of natural resources.
      Citation: Separations
      PubDate: 2022-06-27
      DOI: 10.3390/separations9070161
      Issue No: Vol. 9, No. 7 (2022)
  • Separations, Vol. 9, Pages 162: An Efficient Approach for Separating
           Essential Oil and Polysaccharides Simultaneously from Fresh Leaves of
           Guajava by Microwave-Mediated Hydrodistillation with Lithium Salts and
           Antibacterial Activity of Essential Oil

    • Authors: Xiaonan Zhang, Yan Huang, Lubin Zhang, Hongwei Zhu, Yaqian Niu, Yimin An, Zhiwei Liu
      First page: 162
      Abstract: The essential oils and polysaccharides from guava leaves have important functions. In the process of microwave extraction of plant essential oils and polysaccharides, pretreatment with lithium salts solution is helpful to increase the extraction rate. The experiment was conducted using a single factor method. Results were optimized by principal component analysis and response surface optimization. The optimal conditions were: LiCl dosage 45 μmol, microwave time 40 min, liquid-solid ratio 10, homogenization time 4.2 min, liquid-material ratio 10, and microwave irradiation power 700 W. The highest yield of essential oil and polysaccharide were 10.27 ± 0.58 mL/kg dry weight (DW) and 50.31 ± 1.88 g/kg·DW, respectively. Three verification experiments showed that the extraction rate of the microwave method was higher than that of the traditional heating method. In addition, the bacteriostatic zones reached the maximum 23.7 ± 0.11 mm when the concentration was 40 μL/mL, and the above results have practical significance.
      Citation: Separations
      PubDate: 2022-06-27
      DOI: 10.3390/separations9070162
      Issue No: Vol. 9, No. 7 (2022)
  • Separations, Vol. 9, Pages 163: Recent Advances in Separation and Analysis
           of Saponins in Natural Products

    • Authors: Yi Wang, Yan Ma, Li Tao, Xiaoyan Zhang, Fusheng Hao, Shipeng Zhao, Lu Han, Changcai Bai
      First page: 163
      Abstract: To better control the quality of saponins, ensure their biological activity and clinical therapeutic effect, and expand the development and application of saponins, this paper systematically and comprehensively reviews the separation and analytical methods of saponins in the past decade. Since 2010, the electronic databases of PubMed, Google Scholar, ISI Web of Science, Science Direct, Wiley, Springer, CNKI (National Knowledge Infrastructure, CNKI), Wanfang Med online, and other databases have been searched systematically. As a result, it is found that ionic liquids and high-performance countercurrent chromatography are the most popular extraction and separation techniques for saponins, and the combined chromatography technique is the most widely used method for the analysis of saponins. Liquid chromatography can be used in combination with different detectors to achieve qualitative or quantitative analysis and quality control of saponin compounds in medicinal materials and their preparations. This paper provides the latest valuable insights and references for the analytical methods and continued development and application of saponins.
      Citation: Separations
      PubDate: 2022-06-27
      DOI: 10.3390/separations9070163
      Issue No: Vol. 9, No. 7 (2022)
  • Separations, Vol. 9, Pages 164: Development of a Methodology to Adapt an
           Equilibrium Buffer/Wash Applied to the Purification of hGPN2 Protein
           Expressed in Escherichia coli Using an IMAC Immobilized Metal Affinity
           Chromatography System

    • Authors: Jorge Juárez-Lucero, María del Rayo Guevara-Villa, Anabel Sánchez-Sánchez, Raquel Díaz-Hernández, Leopoldo Altamirano-Robles
      First page: 164
      Abstract: Protein purification is a complex and non-standardized process; the fact that proteins have different structural types making it difficult to create a standard methodology to obtain them in a pure, soluble, and homogeneous form. The present study shows the selective development of a buffer suitable for proteins of interest that allows high concentrations of hGPN2 protein to be obtained with low polydispersion and high homogeneity and purity. By taking the different reagents used in the construction of different buffers as a basis and performing purifications using different additives in different concentrations to determine the optimal amounts, the developed process helps to minimize the bonds, maintain solubility, release the proteins present in inclusion bodies, and provide an adequate environment for obtaining high concentrations of pure protein. GPN proteins are of unknown function, have not been purified in high concentrations, and have been found as part of the RNA polymerase assembly; if they are not expressed, the cell dies, and overexpression of certain GPN proteins has been linked to decreased survival in patients with invasive ductal carcinoma breast cancer types ER+ and HER2+. The results of the present study show that the use of the buffer developed for recombinant hGPN2 protein expressed in Escherichia coli could be manipulated in order to isolate the protein in a totally pure form and without the use of protease inhibitor tablets. The resulting homogeneity and low polydispersion was corroborated by studies carried out using dynamic dispersion analysis. Thanks to these properties, it can be used for crystallography or structural genomics studies.
      Citation: Separations
      PubDate: 2022-06-28
      DOI: 10.3390/separations9070164
      Issue No: Vol. 9, No. 7 (2022)
  • Separations, Vol. 9, Pages 134: A Brief Review of Chromatography in

    • Authors: Šime Ukić, Danijela Ašperger, Tomislav Bolanča
      First page: 134
      Abstract: Although the Republic of Croatia is a relatively small country geographically, it can boast numerous scientists who have left indelible marks in various scientific fields. However, this paper is exclusively about chromatography as one of the most important analytical techniques of our time. The development of chromatography in the Republic of Croatia and the role that three institutions have played in it—the Faculty of Chemical Engineering and Technology of the University of Zagreb, the Croatian Society of Chemical Engineers, and the Central European Group for Separation Sciences—will be briefly discussed.
      Citation: Separations
      PubDate: 2022-05-27
      DOI: 10.3390/separations9060134
      Issue No: Vol. 9, No. 6 (2022)
  • Separations, Vol. 9, Pages 135: Validation of an Analytical Method for the
           Determination of Thiabendazole in Various Food Matrices

    • Authors: Sun-Il Choi, Xionggao Han, Se-Jeong Lee, Xiao Men, Geon Oh, Doo-Sik Lee, Ok-Hwan Lee
      First page: 135
      Abstract: In many countries, thiabendazole is used as a fungicide to prevent the decay of food and to lengthen storage periods. However, in Korea, thiabendazole is unauthorised and does not have standards or specifications for use as a food additive. In this study, a simple analytical method was developed and validated using the HPLC–PDA method to detect thiabendazole in foods frequently consumed in South Korea. The calibration curve was obtained using samples of solid and liquid foods containing banana and citrus fruits containing concentrations in the range of 0.31–20.00 μg/mL with a satisfactory coefficient of determination (R2) of 0.999. The limit of detection (LOD) values for the solid and liquid food samples were 0.009 and 0.017 μg/mL, respectively, and the limit of quantification (LOQ) values were 0.028 and 0.052 μg/mL. The intra-day and inter-day precision values were less than 1.33% (relative standard deviation), and the recoveries of thiabendazole from spiked solid and liquid food samples ranged from 93.61 to 98.08% at concentration levels of 2.5, 5, and 10 μg/mL. In addition, the expanded uncertainties of the measu-rements ranged from 0.57 to 3.12%. These results showed that the developed method was appropriate for the quantitative analysis of thiabendazole in solid and liquid foods containing banana and citrus fruits.
      Citation: Separations
      PubDate: 2022-05-27
      DOI: 10.3390/separations9060135
      Issue No: Vol. 9, No. 6 (2022)
  • Separations, Vol. 9, Pages 136: Isotopic Characterization of Italian
           Industrial Hemp (Cannabis sativa L.) Intended for Food Use: A First
           Exploratory Study

    • Authors: Marco Calvi, Luana Bontempo, Sarah Pizzini, Lorenzo Cucinotta, Federica Camin, Barbara Stenni
      First page: 136
      Abstract: In this study, Italian industrial hemp (Cannabis sativa L.) intended for food use was isotopically characterized for the first time. The stable isotope ratios of five bioelements were analyzed in different parts of the plant (i.e., roots, stems, inflorescences, and seeds) sampled in eight different regions of Italy, and in five hemp seed oils. The values of δ2H, δ13C, δ18O, and δ34S differed according to the latitude and, therefore, to the geographical origin of the samples and the climate conditions of plant growth, while the δ15N values allowed us to distinguish between crops grown under conventional and organic fertilization. The findings from this preliminary study corroborate the reliability of using light stable isotope ratios to characterize hemp and its derived food products and contribute to the creation of a first isotopic database for this plant, paving the way for future studies on authentication, traceability, and verification of organic labeling.
      Citation: Separations
      PubDate: 2022-05-29
      DOI: 10.3390/separations9060136
      Issue No: Vol. 9, No. 6 (2022)
  • Separations, Vol. 9, Pages 137: Optimization of Steam Distillation Process
           and Chemical Constituents of Volatile Oil from Angelicae sinensis Radix

    • Authors: Na Wan, Jing Lan, Zhenfeng Wu, Xinying Chen, Qin Zheng, Xingchu Gong
      First page: 137
      Abstract: In this study, the steam distillation process of volatile oil from Angelicae sinensis Radix was optimized according to the concept of quality-by-design. A homemade glass volatile oil extractor was used to achieve better cooling of the volatile oil. First, the soaking time, distillation time, and liquid–material ratio were identified as potential critical process parameters by consulting the literature. Then, the three parameters were investigated by single factor experiments. The volatile oil yield increased with the extension in the distillation time, and first increased and then decreased with the increase in soaking time and liquid–material ratio. The results confirmed that soaking time, distillation time, and liquid–material ratio were all critical process parameters. The kinetics models of volatile oil distillation from Angelicae sinensis Radix were established. The diffusion model of spherical particle was found to be the best model and indicated that the major resistance of mass transfer was the diffusion of volatile oil from the inside to the surface of the medicinal herb. Furthermore, the Box–Behnken experimental design was used to study the relationship between the three parameters and volatile oil yield. A second-order polynomial model was established, with R2 exceeding 0.99. The design space of the volatile oil yield was calculated by a probability-based method. In the verification experiments, the average volatile oil yield reached 0.711%. The results showed that the model was accurate and the design space was reliable. In this study, 21 chemical constituents of volatile oil from Angelicae sinensis Radix were identified by gas chromatograph-mass spectrometer(GC-MS), accounting for 99.4% of the total volatile oil. It was found that the content of Z-ligustilide was the highest, accounting for 85.4%.
      Citation: Separations
      PubDate: 2022-05-30
      DOI: 10.3390/separations9060137
      Issue No: Vol. 9, No. 6 (2022)
  • Separations, Vol. 9, Pages 138: Phytochemical Characterization and Heavy
           Metal and Thermal Analyses of Saussurea hypoleuca Root and Evaluation of
           Its Anthelmintic and Antioxidant Activity In Vitro and In Silico

    • Authors: Sameh S. Elhady, Numera Arshad, Saiqa Ishtiaq, Roula Bayram, Adnan Amin, Hanin A. Bogari, Reda F. A. Abdelhameed, Fadia S. Youssef, Mohamed L. Ashour
      First page: 138
      Abstract: Phytochemical characterization of the ethyl acetate fraction of Saussurea hypoleuca root extract resulted in the isolation of oleic acid (1) and luteolin (2), which were isolated for the first time from Saussurea hypoleuca root. A heavy metal analysis of the root powder performed using atomic absorption spectroscopy showed that the contents of iron, cadmium, lead, zinc, nickel, and copper were within the certified limits according to the WHO guidelines. Differential scanning calorimetry (DSC) revealed its crystalline and amorphous nature; meanwhile, standardization of the root with UHPLC revealed the presence of 14.79 ± 0.015 µg/mL of luteolin. Both the total methanol extract and the ethyl acetate fraction of the plant root held significant anthelmintic activity. Oleic acid and luteolin exhibited potent antioxidant activity, evidenced by their IC50 values, which were equal to 47.0 and 119.8 µg/mL, respectively, in a 2, 2-diphenyl-1-picrylhydrazyl (DPPH) scavenging assay. In silico studies showed that luteolin exerted the highest fitting within the binding sites of NADPH oxidase (Nox). For myeloperoxidase (MP), oleic acid revealed the best fitting in its active sites. The results of ADMET (absorption, distribution, metabolism, excretion, and toxicity) and TOPKAT (toxicity prediction) protocols revealed acceptable pharmacodynamic and pharmacokinetic characteristics, in addition to reasonable toxicity characteristics for both compounds. Thus, they can be incorporated into pharmaceutical dosage forms to combat oxidative stress.
      Citation: Separations
      PubDate: 2022-05-30
      DOI: 10.3390/separations9060138
      Issue No: Vol. 9, No. 6 (2022)
  • Separations, Vol. 9, Pages 139: A Review of the Removal of Dyestuffs from
           Effluents onto Biochar

    • Authors: Prakash Parthasarathy, Samra Sajjad, Junaid Saleem, Mohammad Alherbawi, Gordon Mckay
      First page: 139
      Abstract: The study provides a review of various applications of biomass-derived biochars, waste-derived biochars, and modified biochars as adsorbent materials for removing dyestuff from process effluents. Processing significant amounts of dye effluent discharges into receiving waters can supply major benefits to countries which are affected by the water crisis and anticipated future stress in many areas in the world. When compared to most conventional adsorbents, biochars can provide an economically attractive solution. In comparison to many other textile effluent treatment processes, adsorption technology provides an economic, easily managed, and highly effective treatment option. Several tabulated data values are provided that summarize the main characteristics of various biochar adsorbents according to their ability to remove dyestuffs from wastewaters.
      Citation: Separations
      PubDate: 2022-05-30
      DOI: 10.3390/separations9060139
      Issue No: Vol. 9, No. 6 (2022)
  • Separations, Vol. 9, Pages 140: Quantitative Analysis of Anthocyanins in
           Grapes by UPLC-Q-TOF MS Combined with QAMS

    • Authors: Xue Li, Wei Wang, Suling Sun, Junhong Wang, Jiahong Zhu, Feng Liang, Yu Zhang, Guixian Hu
      First page: 140
      Abstract: A method for quantifying the anthocyanins in grapes was firstly developed by ultra-high performance liquid chromatography-quadrupole-time of flight mass spectrometry (UPLC-Q-TOFMS) combined with quantitative analysis of multi-components by single marker (QAMS). A total of 10 main anthocyanins were analyzed by using peonidin 3-O-glucoside as the reference standard. The accuracy of this method was evaluated by an established and validated external standard quantification method with 10 reference compounds. The standard method difference (SMDs) of the quantification results between QAMS and the external standard methodwasless than 15%. Furthermore, the QAMS method was used to analyzefour batches of grapes and the data was compared with those obtained using the external standard method. No significant difference wasobtained in the results obtained by both methods. These results indicated that the QAMS method could accurately determine the anthocyanins in grapes. This method can provide a basis to address the absence of reference standards for analyzing anthocyanins in other foods.
      Citation: Separations
      PubDate: 2022-06-02
      DOI: 10.3390/separations9060140
      Issue No: Vol. 9, No. 6 (2022)
  • Separations, Vol. 9, Pages 141: Measuring Vitamin D3 Metabolic Status,
           Comparison between Vitamin D Deficient and Sufficient Individuals

    • Authors: Castillo-Peinado, Calderón-Santiago, Herrera-Martínez, León-Idougourram, Gálvez-Moreno, Sánchez-Cano, Bouillon, Quesada-Gómez, Priego-Capote
      First page: 141
      Abstract: The main branch of vitamin D3 metabolism involves several hydroxylation reactions to obtain mono-, di- and trihydroxylated metabolites, including the circulating and active forms—25(OH)D3 and 1,25(OH)2D3, respectively. However, most clinical trials strictly target the determination of 25(OH)D3 to offer a view of the metabolic status of vitamin D3. Due to the growing interest in expanding this restricted view, we have developed a method for measuring vitamin D3 metabolism by determination of vitamin D3, 25(OH)D3, 24,25(OH)2D3, 1,25(OH)2D3 and 1,24,25(OH)3D3 in human plasma. The method was based on SPE–LC–MS/MS with a large volume injection of human plasma (240 µL). Detection of di- and trihydroxymetabolites, found at the picogram per milliliter level, was attained by the combined action of high preconcentration and clean-up effects. The method allows obtaining information about ratios such as the known vitamin D metabolite ratio (24,25(OH)2D3/25(OH)D3), which can provide complementary views of vitamin D3 metabolic status. The method was applied to a cohort of obese patients and a reference cohort of healthy volunteers to find metabolic correlations between target analytes as well as differences as a function of vitamin D levels within and between cohorts.
      Citation: Separations
      PubDate: 2022-06-03
      DOI: 10.3390/separations9060141
      Issue No: Vol. 9, No. 6 (2022)
  • Separations, Vol. 9, Pages 142: Efficient Extraction of an Anthraquinone
           Physcion Using Response Surface Methodology (RSM) Optimized
           Ultrasound-Assisted Extraction Method from Aerial Parts of Senna
           occidentalis and Analysis by HPLC-UV

    • Authors: Perwez Alam, Omar M. Noman, Rashed N. Herqash, Omer M. Almarfadi, Ali Akhtar, Ali S. Alqahtani
      First page: 142
      Abstract: In this experiment, the Box–Behnken design (BBD) of the response surface methodology (RSM) was used to optimize the ultrasound-assisted extraction variables (liquid-to-solid ratio, extraction temperature, and time) to obtain the maximum yield of physcion from the methanol extract of S. occidentalis (aerial parts). The analysis of physcion in the extracts obtained by using the optimized extraction condition was carried out in a gradient system by the HPLC-UV method with 0.5% formic acid in ultra-pure water (Solvent A) and acetonitrile (Solvent B) in different ratios as the mobile phase. The optimal extraction conditions for the maximum physcion extraction were found as: a liquid-to-solid ratio of 20.16 mL/g, extraction temperature of 52.2 °C, and extraction time of 46.6 min. Under these optimal ultrasonic extraction conditions, the experimental yield (% w/w of the dried extract) of the physcion was found to be 2.43%, which agreed closely with the predicted value (2.41). The experimental value was consistent with the value predicted by the RSM model, thus validating the fitness of the employed model and the success of the RSM in optimizing the extraction conditions. In future, this optimized ultrasonic extraction condition can be used in the maximum extraction of physcion from marketed herbal supplements containing S. occidentalis as well as other Senna species.
      Citation: Separations
      PubDate: 2022-06-06
      DOI: 10.3390/separations9060142
      Issue No: Vol. 9, No. 6 (2022)
  • Separations, Vol. 9, Pages 143: Sensitive Ion-Chromatographic
           Determination of Citric Acid in Urine

    • Authors: Michele Petrarulo, Marta Leporati, Federica Pullara, Maura Frattini, Vita Nannavecchia, Martino Marangella, Domenico Cosseddu
      First page: 143
      Abstract: Urine citrate analysis is relevant in the screening and monitoring of patients with calcium nephrolithiasis. A sensitive, fast, easy, and low-maintenance ion chromatographic (IC) method with conductivity detection for the analysis of urine citrate is developed and validated. Its application on true samples is also reported. Sample urine is diluted with a water solution containing internal standard (IS) before the chromatographic assay. The isocratic chromatographic run time is twenty-five minutes, using sodium hydroxide aqueous solution as the mobile phase. The method is fully validated as a quantitative method to objectively demonstrate its applicability for the intended use. The analytical response is linear in the 0.08–10.4 mmol/L concentration range. Precision and accuracy studies carried out on spiked urine and internal quality control samples reveal an imprecision CV% lower than 11% and an accuracy between 85 and 103%. The stability of citrate in urine samples is also evaluated. An easy, rapid, and low-maintenance, cost-effective IC method for urinary citrate determination is developed and validated. Internal standardization improves reliability and precision. The method has been currently used in our laboratory over recent years to analyze more than 1000 samples per year.
      Citation: Separations
      PubDate: 2022-06-06
      DOI: 10.3390/separations9060143
      Issue No: Vol. 9, No. 6 (2022)
  • Separations, Vol. 9, Pages 144: Comparative Study of the Selective
           Sorption of Organic Dyes on Inorganic Materials—A Cost-Effective

    • Authors: Anifat Adenike Bankole, Vijo Poulose, Tholkappiyan Ramachandran, Fathalla Hamed, Thies Thiemann
      First page: 144
      Abstract: Educational and research laboratories often produce relatively small amounts of highly diverse organic wastes. Treating waste can contribute significantly to the cost of running laboratories. This study introduced a simple and economical waste management system such that readily available used chromatography-grade inorganic materials, such as silica and alumina (basic and acidic), are utilized to treat remnant dye solutions and solution wastes from educational and small research laboratories. To recycle the adsorbents, they were heated to 600 °C, where the adsorbates were combusted. The results showed that acidic alumina is an effective adsorbent material for azo dyes and anionic dyes/stains, as well as textile dyes, with a 98 to 100% removal efficiency. Furthermore, alumina and silica possess excellent regeneration properties, where the dye removal efficiency of the materials was retained after regeneration at 600 °C. The adsorption properties of the materials were compared with those of aliginite and activated biomass from coffee grounds. Kinetic and thermodynamic studies of the sorption processes on the different materials were carried out. Overall, the inorganic materials used were efficient at removing contaminating remnant organic dyes stemming from educational and small research laboratories.
      Citation: Separations
      PubDate: 2022-06-07
      DOI: 10.3390/separations9060144
      Issue No: Vol. 9, No. 6 (2022)
  • Separations, Vol. 9, Pages 145: HPLC-MS, GC and NMR Profiling of Bioactive
           Lipids of Human Milk and Milk of Dairy Animals (Cow, Sheep, Goat, Buffalo,
           Camel, Red Deer)

    • Authors: Kirill Lagutin, Andrew MacKenzie, Stephen Bloor, Dawn Scott, Mikhail Vyssotski
      First page: 145
      Abstract: For non-bovine milks, information regarding bioactive lipids is fragmented, unreliable or unavailable. The purpose of the current study was to analyse bioactive lipids in the milk of dairy animals using modern analytical methods to achieve the most reliable results. Bioactive lipids in human milk were also analysed and used as a reference. A suite of modern analytical methods was employed, namely High Performance Liquid Chromatography-Mass Spectrometry (HPLC-MS), Gas Chromatography (GC) and Nuclear Magnetic Resonance (NMR). The total lipid content was determined, and phospholipid, fatty acid, neutral glycosphingolipids and ganglioside (GM3 and GD3) levels were measured. Lipid classes in selected milks were reliably characterised for the first time, including gangliosides in deer, camel and sheep; cerebrosides in deer, camel and buffalo; plasmalogens in deer, buffalo and goat and phospholipids in deer. Our study demonstrated the advantage of utilising a range of analytical techniques in order to characterise a diverse set of bioactive lipids.
      Citation: Separations
      PubDate: 2022-06-07
      DOI: 10.3390/separations9060145
      Issue No: Vol. 9, No. 6 (2022)
  • Separations, Vol. 9, Pages 146: Evaluation of the Base Stability of
           Hydrophilic Interaction Chromatography Columns Packed with Silica or
           Ethylene-Bridged Hybrid Particles

    • Authors: Thomas H. Walter, Bonnie A. Alden, Kenneth Berthelette
      First page: 146
      Abstract: Stability as a function of mobile phase pH is an important consideration when selecting a chromatographic column. While the pH stability of reversed-phase columns is widely studied, there are relatively few reports of the stability of hydrophilic interaction chromatography (HILIC) columns. We evaluated the stability of silica and ethylene-bridged hybrid HILIC columns when used with mobile phases containing basic buffers. The predominant mode of column degradation observed in our studies was a decrease in efficiency due to voiding, resulting from the hydrolysis of the silica particles. Associated with this were increases in tailing factors. Retention factor changes were also noted but were smaller than the efficiency losses. The dependence of the rate of efficiency decrease on the key variables of temperature, mobile phase pH and water content were studied for an unbonded silica column. The effect of the acetonitrile concentration on the pH of the mixed aqueous/acetonitrile mobile phases was also investigated. Using conditions found to cause a 50% decrease in efficiency after approximately five hours of exposure to the basic solution, we evaluated eight different commercially available HILIC columns containing silica or ethylene-bridged hybrid particles. The results show large differences between the stability of the silica and ethylene-bridged hybrid particle stationary phases, with the latter exhibiting greater stability.
      Citation: Separations
      PubDate: 2022-06-08
      DOI: 10.3390/separations9060146
      Issue No: Vol. 9, No. 6 (2022)
  • Separations, Vol. 9, Pages 147: Evaluation of Greenness of LC-MS
           Chromatographic Methods for Simultaneous Analysis of Mixtures of
           Serotonin, Dopamine, Acetylcholine, GABA and Glutamate: AGREE Tool

    • Authors: Atiah H. Almalki, Izzeddin Alsalahat, Muath A. Alharthi, Dibya Sundar Panda, Albandary Almahri, Ibrahim A. Naguib
      First page: 147
      Abstract: The analytical GREEnness metric (AGREE) tool is widely used as a reliable greenness assessment method for chromatographic analyses. The AGREE tool has the ability to determine the greenness of analytical methods in terms of both quality and quantity, whereas other commonly used methods assess the greenness either quantitatively or qualitatively. Greenness profiles of six chromatographic methods for simultaneous estimations of serotonin, dopamine, acetylcholine, GABA and glutamate were assessed using AGREE and NEMI tools as a case study. The AGREE assessment tool proved to be user-friendly, and provides a full profile of assessment, hence it can be described as the tool of choice for the assessment of LC-MS chromatographic methods. For optimum application, the weights of 4 of the 12 assessment criteria were set high (weight of four) due to their importance, namely criteria number 7 (waste), number 8 (analysis thruput/number of analytes per run), number 11 (toxicity) and number 12 (operator’s safety). Setting proper weights of the assessment criteria contributed significantly to the discrimination of greenness of the compared methods. The selected greenest method for the analysis of the proposed quinary mixture showed an AGREE tool pictogram with a 0.66 score. Additionally, the selected method allows simultaneous estimation of seven constituents in total. It offers high sensitivity, allowing detection of acetylcholine, serotonin and glutamate at levels as low as 2 pg, and dopamine, norepinephrine, GABA and glycine at levels as low as 10 pg, and finally offers fast analysis where all components can be analyzed within 5 min.
      Citation: Separations
      PubDate: 2022-06-08
      DOI: 10.3390/separations9060147
      Issue No: Vol. 9, No. 6 (2022)
  • Separations, Vol. 9, Pages 148: Current Role of Mass Spectrometry in the
           Determination of Pesticide Residues in Food

    • Authors: Maykel Hernández-Mesa, David Moreno-González
      First page: 148
      Abstract: The extensive use of pesticides represents a risk to human health. Consequently, legal frameworks have been established to ensure food safety, including control programs for pesticide residues. In this context, the performance of analytical methods acquires special relevance. Such methods are expected to be able to determine the largest number of compounds at trace concentration levels in complex food matrices, which represents a great analytical challenge. Technical advances in mass spectrometry (MS) have led to the development of more efficient analytical methods for the determination of pesticides. This review provides an overview of current analytical strategies applied in pesticide analysis, with a special focus on MS methods. Current targeted MS methods allow the simultaneous determination of hundreds of pesticides, whereas non-targeted MS methods are now applicable to the identification of pesticide metabolites and transformation products. New trends in pesticide analysis are also presented, including approaches for the simultaneous determination of pesticide residues and other food contaminants (i.e., mega-methods), or the recent application of techniques such as ion mobility–mass spectrometry (IM–MS) for this purpose.
      Citation: Separations
      PubDate: 2022-06-09
      DOI: 10.3390/separations9060148
      Issue No: Vol. 9, No. 6 (2022)
  • Separations, Vol. 9, Pages 149: Natural Factors on Heterogenetic
           Accumulations of PTEs in Sloping Farmland in a Typical Small Mountainous
           Watershed in Southwest China

    • Authors: Ya Gao, Bihan Gu, Lingchen Mao, Daofang Zhang, Hong Tao
      First page: 149
      Abstract: High potential toxic element (PTE) concentrations in soils that exceed local regulatory threshold values have been reported in non-polluted mountainous areas worldwide. However, there have been few studies that have comprehensively investigated the contribution of natural factors including the parental material, pedogenesis processes and physiochemical properties of soils on the distribution of PTEs in these soils. Therefore, in this study, we studied the distribution of 13 PTEs in sloping farmland soils collected from a mountainous watershed in Guizhou Province, Southwest China. The contributions of natural influencing factors were analyzed using a geostatistical analysis and a geographic detector method. All of the PTEs were unevenly distributed, especially Sb, and the average contents of V, Cr, Co, Ni, Cu, Zn, As, Mo, Cd, Sb, Tl, Pb and Hg were 57.15, 36.20, 4.61, 12.61, 13.36, 63.50, 11.94, 0.78, 0.37, 6.44, 0.48, 27.42 and 0.36mg/kg, respectively. The proportion of samples with Cd, Hg and As exceeding the screening value of the soil pollution risk of agricultural land in China was 46.7%, 5.9% and 4.4%, respectively. Except for Cd and Pb, the q values of the PTEs calculated from the geographical detector were above 0.05, indicating that altitude changes, which affect the pedogenesis process, have a great impact on the spatial distribution. Stratigraphic factors contributed greatly to the distribution of Co, Ni and Cu, which indicates their similarity in parental material. The combined effect of clay content, topographic factors and agricultural land types had the strongest explanatory power for V, Cr, Mo and Pb. The distributions of As, Sb, Tl and Hg are strongly associated with a potential source of mercury ore, and their accumulation is also enhanced by the adsorption on soil clay. Agricultural As also contributes to its distribution.
      Citation: Separations
      PubDate: 2022-06-10
      DOI: 10.3390/separations9060149
      Issue No: Vol. 9, No. 6 (2022)
  • Separations, Vol. 9, Pages 150: Nanoporosity and Isosteric Enthalpy of
           Adsorption of CH4, H2, and CO2 on Natural Chabazite and Exchanged

    • Authors: Miguel Ángel Hernández, Karla Quiroz-Estrada, Gabriela I. Hernandez-Salgado, Roberto Ignacio Portillo, Juana Deisy Santamaría-Juárez, Ma de los Ángeles Velasco, Efraín Rubio, Vitalii Petranovskii
      First page: 150
      Abstract: This paper describes the isosteric enthalpy through narrow pores at low levels of coverage through adsorption of CO2, CH4, and H2 on pores in natural chabazite exchanged with aqueous solutions of Na+, Mg2+, and Ca2+ salts at different concentrations, and with variable time and temperature of treatment. Experimental data of CO2, CH4, and H2 adsorption were treated by the Freundlich and Langmuir equations. Complementarily, the degree of interaction of these gases with these zeolites was evaluated by the evolution of isosteric enthalpy of adsorption. The exchange with Mg2+ and Na+ favors an increase in the adsorption capacity for CO2. while that of Ca2+ and Mg2+ favor adsorption through to H2 and CH4. These cations occupy sites in strategic positions S4 and S4’, which are located in the channels and nanocavities of these zeolites. The presence of Ca2+ and Mg2+ at S4 and S4′ sites causes increased adsorption into the nanocavities and on the external area of the ion-exchanged zeolites. Depending on the conditions of the exchange treatment, Ca2+ and Mg2+, and Na+ were found to be most favorable, well distributed, and accessible for CO2, CH4, and H2 adsorption.
      Citation: Separations
      PubDate: 2022-06-10
      DOI: 10.3390/separations9060150
      Issue No: Vol. 9, No. 6 (2022)
  • Separations, Vol. 9, Pages 151: Modeling and Life Cycle Assessment of a
           Membrane Bioreactor–Membrane Distillation Wastewater Treatment
           System for Potable Reuse

    • Authors: Callan J. Glover, James A. Phillips, Eric A. Marchand, Sage R. Hiibel
      First page: 151
      Abstract: Wastewater treatment for indirect potable reuse (IPR) is a possible approach to address water scarcity. In this study, a novel membrane bioreactor–membrane distillation (MBR-MD) system was evaluated to determine the environmental impacts of treatment compared to an existing IPR facility (“Baseline”). Physical and empirical models were used to obtain operational data for both systems and inform a life cycle inventory. Life cycle assessment (LCA) was used to compare the environmental impacts of each system. Results showed an average 53.7% reduction in environmental impacts for the MBR-MD system when waste heat is used to operate MD; however, without waste heat, the environmental impacts of MBR-MD are significantly higher, with average impacts ranging from 218% to 1400% greater than the Baseline, depending on the proportion of waste heat used. The results of this study demonstrate the effectiveness of the novel MBR-MD system for IPR and the reduced environmental impacts when waste heat is available to power MD.
      Citation: Separations
      PubDate: 2022-06-13
      DOI: 10.3390/separations9060151
      Issue No: Vol. 9, No. 6 (2022)
  • Separations, Vol. 9, Pages 152: Comparative Study of Natural Antioxidants
           from Glycine max, Anethum graveolensand Pimpinella anisum Seed and
           Sprout Extracts Obtained by Ultrasound-Assisted Extraction

    • Authors: Fanica Balanescu, Anna Cazanevscaia Busuioc, Andreea Veronica Dediu Botezatu, Steluta Gosav, Sorin Marius Avramescu, Bianca Furdui, Rodica Mihaela Dinica
      First page: 152
      Abstract: The study aimed to evaluate the antioxidant potential of sprout and seed extracts from three species of plants, namely Glycine max (GMsp-sprouts, GMsd-seeds), Anethum graveolens (AGsp-sprouts, AGsd-seeds) and Pimpinella anisum (PAsp-sprouts, PAsd-seeds), which are widely accepted by consumers and have various applications in food flavoring, and also in natural medical treatments in the pharmaceutical industries. These plants are rich in valuable compounds that show a remarkable antioxidant power and are associated with many health benefits. Ethanol extracts were obtained by ultrasound-assisted extraction and they were comparatively evaluated for their in vitro antioxidant properties. The extracts were characterized by HPTLC, HPLC-DAD, total phenol content (TPC), total flavonoid content (TFC) analysis and antioxidant activities with different assays, such as total antioxidant capacity (TAC), 2,2′-azino-bis (3- ethylbenzothiazoline-6-sulfonic acid) radical cation decolorization assay (ABTS), 1,1-diphenyl 1-2-picryl-hydrazyl (DPPH) and iron binding ability of chelators. Our results showed that the sprout and seed extracts of the studied plants exhibited a high content of phytochemicals and promising antioxidant properties. The highest polyphenols content was detected for AGsd (53.02 ± 0.57 mg/g DW), PAsd (48.75 ± 0.34 mg/g DW) and the highest flavonoids content for PAsp (26.84 ± 0.57 mg/g DW). Moreover, the presence of valuable compounds was demonstrated by using HPTLC, FT-IR and HPLC-DAD techniques. In order to have a better understanding of the relationship between the biological properties and the electronic structure, a molecular modelling study of genistein was also conducted. Our approach to the comparative assessment of these three plant species was based on a priori knowledge from literature data; however, this study demonstrated that these plant extracts of seeds and also sprouts are excellent sources of natural antioxidants. Significant additional differences that were found in the phytochemical composition could be exploited in future research for pharmaceutical purposes.
      Citation: Separations
      PubDate: 2022-06-13
      DOI: 10.3390/separations9060152
      Issue No: Vol. 9, No. 6 (2022)
  • Separations, Vol. 9, Pages 153: Study on Screening Mechanism and Numerical
           Simulation for Crashed Concrete Particles by Using DEM

    • Authors: Deyi He, Chusheng Liu
      First page: 153
      Abstract: Recycling waste concrete has become a large problem in developing countries. The aim of this work is to provide guidance for screening concrete particles and improving screening efficiency. First, the elastoplastic collision model is established for calculating the coefficient of restitution for concrete particles with different compressive strengths. Then, a bar circular vibrating screen is applied to simulate the screening process of concrete particles by using the discrete element method (DEM). The optimal vibrating parameters, which contain amplitude, frequency and inclination angles, is analyzed for the representative concrete particles containing C15, C45 and C80 by comparing the screening efficiency. The results show that the optimal screening parameters of amplitude and frequency is smaller with the increase in the compressive strength of the concrete particles. Appropriately, the large inclination angle is suitable for screening fine concrete particles with a gap vibrating screen. This work should be helpful for the screening process of concrete waste particles and provides a theoretical basis and simulation case for screening and recycling other particles, such as sand, stone, iron ore and copper ore. In the screening processes of construction wastes, the optimal screening parameters can be selected quickly by calculating the coefficient of restitution and adopting the DEM simulation.
      Citation: Separations
      PubDate: 2022-06-14
      DOI: 10.3390/separations9060153
      Issue No: Vol. 9, No. 6 (2022)
  • Separations, Vol. 9, Pages 154: Thenoyltrifluoroacetone: Preferable
           Molecule for Solvent Extraction of Metals—Ancient Twists to New

    • Authors: Maria Atanassova
      First page: 154
      Abstract: A review of the investigations devoted to the solvent extraction processes of metal ions with a chelating ligand thenoyltrifluoroacetone (HTTA) is presented herein. It seems that this molecule has been preferred in the field for more than half a century, and that it is used very often as an extractant for almost all metals. The main objective of the present review is also to provide an overview of the synergistic solvent extraction of lanthanoids, particularly with the use of a β-diketone−neutral mixture. Based on the previous published results in the open literature, the extraction efficiency has been examined in detail and discussed further mainly in terms of the corresponding equilibrium constants among other outlined, so-important parameters. Major conclusions on the role of ligating groups of extractants towards the mechanism, an improved extraction enhancement, and selectivity are additionally provided. The fact that ionic liquids (ILs) appear to be replacing volatile diluents in the field of the liquid–liquid extraction of metals, again with the participation of this β-diketone, is not surprising. As is well known, a very efficient and simple way to determine the stoichiometry of the extracted species in the organic phase is by the simple use of the slope analysis method; however, it is sometimes difficult to perform, either because it somehow requests good solubility of the ligand or because obtained slopes are quite often far from integer values in ILs.
      Citation: Separations
      PubDate: 2022-06-14
      DOI: 10.3390/separations9060154
      Issue No: Vol. 9, No. 6 (2022)
  • Separations, Vol. 9, Pages 155: A Study of Copper (II) Ions Removal by
           Reverse Osmosis under Various Operating Conditions

    • Authors: Ramzi H. Harharah, Ghassan M. T. Abdalla, Abubakr Elkhaleefa, Ihab Shigidi, Hamed N. Harharah
      First page: 155
      Abstract: The study aims to treat artificial wastewater contaminated with copper (II) ions by reverse osmosis using (SEPA CF042 Membrane Test Skid-TFC BW30XFR). Several concentrations of feedstock were prepared. Different operating pressure, temperature, and flow rate were applied. The effect of these operating conditions on both the amount of Cu (II) removal and the permeate flux was monitored. The results of the study revealed that both the permeate flux and Cu (II) removal amount were directly proportional to the operating pressure and feed temperature but inversely proportional to the feed concentration. In contrast, the feed flow rate showed a negligible effect on the permeate flux and Cu (II) removal amount. The temperature correction factor (TCF) of the membrane was calculated and was found to be directly proportional to the feed temperature but inversely proportional to the applied pressure. It was seen that the concentration and flow rate of that feed did not affect the temperature correction factor. Mathematical models have been developed based on these experimental data for both permeate flux and the Cu (II) removal. It was noted that the permeate flux model matched the experimental data, while the Cu (II) removal model did not show a perfect match. In addition to the above, the research highlights for subsequent studies the possibility of a deep link between experimental work and mathematical models.
      Citation: Separations
      PubDate: 2022-06-20
      DOI: 10.3390/separations9060155
      Issue No: Vol. 9, No. 6 (2022)
  • Separations, Vol. 9, Pages 103: Multivariate Optimization of
           Chromatographic Conditions for Rapid Simultaneous Quantification of
           Antidiarrheal Drugs in Formulation Using Surface Response Methodology

    • Authors: Mahesh Attimarad, Katharigatta Narayanaswamy Venugopala, Muhammad S. Chohan, Pottathil Shinu, Marysheela David, Effren II Plaza Molina, Anroop Balachandran Nair, Nagaraja Sreeharsha, Abdulrahman Ibrahim Altaysan, Abdulmalek Ahmed Balgoname
      First page: 103
      Abstract: A combination of antibiotics and antiprotozoal and antisecretory medicines has been prescribed for the treatment of diarrhea. A rapid, reproducible liquid chromatographic procedure was established for the concurrent analysis of metronidazole (MET), ofloxacin (OFL), and racecadotril (RAC) in suspension. The Box–Behnken design, a full factorial multivariate optimization technique, was utilized to optimize chromatographic parameters with fewer runs. The separation of MET, OFL, and RAC was accomplished within 3.2 min, using a Zorbax C18 high-performance liquid chromatography column with a simple mobile phase comprising acetonitrile (55 vol.%): methanol (10 vol.%):20 mM phosphate buffer (35 vol.%, pH 6, regulated with ortho-phosphoric acid). The mobile phase was pumped in the isocratic mode at a rate of 1.4 mL/min at ambient temperature. Analytes were monitored by adjusting the wavelength at 295 nm for MET and OFL and 231 nm for RAC. Validation of the proposed HPLC method exhibited linearity in the concentration of 20–250 µg/mL, 10–150 µg/mL, and 5–80 µg/mL for MET, OFL, and RAC respectively, along with an excellent regression coefficient (r2 > 0.999). The accuracy and precision of the chromatographic procedure were also evidenced by the low percent relative error and relative standard deviation. A Pareto chart developed by the two-factor interaction (2FI) study confirmed that the method was robust, as the slight variation in a single factor had no significant influence on the assay outcomes. Lastly, the developed HPLC process was utilized for the concurrent quantification of MET, OFL, and RAC in liquid oral preparation. Furthermore, when the assay results were compared to the described techniques, it was discovered that there was no significant difference in the accuracy and precision of the results. Hence, the developed rapid HPLC method could be employed for the quality control study of a preparation comprising of MET, OFL, and RAC in industries and regulatory authority laboratories.
      Citation: Separations
      PubDate: 2022-04-21
      DOI: 10.3390/separations9050103
      Issue No: Vol. 9, No. 5 (2022)
  • Separations, Vol. 9, Pages 104: Analysis of Multiclass Pesticide Residues
           in Tobacco by Gas Chromatography Quadrupole Time-of-Flight Mass
           Spectrometry Combined with Mini Solid-Phase Extraction

    • Authors: Rui Bie, Jiguang Zhang, Yunbai Wang, Dongmei Jin, Rui Yin, Bin Jiang, Jianmin Cao
      First page: 104
      Abstract: A screening method using gas chromatography quadrupole time-of-flight mass spectrometry (GC-QTOF/MS) combined with mini solid-phase extraction (mini-SPE) was established for the quantification and validation of multiclass pesticide residues in tobacco. The method was quicker and easier, with sample purity higher than that obtained by traditional SPE and dispersed-SPE. Box-Behnken design, an experimental design for response-surface methodology, was used to optimize the variables affecting the target pesticide recovery. Under the optimized conditions, 92% of the pesticides showed satisfactory recoveries of 70%–120% with precision <20% at spiking levels of 50, 250, and 500 ng/g. The limits of detection and quantification for all the analyses were 0.05–29.9 ng/g and 0.20–98.8 ng/g, respectively. In addition, a screening method based on the retention time and a homebuilt high-resolution mass spectrometry database were established. Under the proposed screening parameters and at spiking levels of 50, 100, and 500 ng/g, 76.6%, 94.7%, and 99.0% multiclass pesticide residues were detected, respectively, using the workflow software. The validated method was successfully applied to the analysis of real tobacco samples. Thus, the combination of mini-SPE and GC-QTOF/MS serves as a suitable method for the quantitative analysis and rapid screening of multiclass pesticide residues in tobacco.
      Citation: Separations
      PubDate: 2022-04-21
      DOI: 10.3390/separations9050104
      Issue No: Vol. 9, No. 5 (2022)
  • Separations, Vol. 9, Pages 105: Green and Simple Extraction of Arsenic
           Species from Rice Flour Using a Novel Ultrasound-Assisted Enzymatic
           Hydrolysis Method

    • Authors: Xiao Li, Qian Ma, Chao Wei, Wei Cai, Huanhuan Chen, Rui Xing, Panshu Song
      First page: 105
      Abstract: It is well established that arsenic (As) has many toxic compounds, and in particular, inorganic As (iAs) has been classified as a type-1 carcinogen. The measuring of As species in rice flour is of great importance since rice is a staple of the diet in many countries and a major contributor to As intake in the Asian diet. In this study, several solvents and techniques for the extraction of As species from rice flour samples prior to their analysis by HPLC-ICP-MS were investigated. The extraction methods were examined for their efficiency in extracting various arsenicals from a rice flour certified reference material, NMIJ-7532a, produced by the National Metrology Institute of Japan. Results show that ultrasound-assisted extraction at 60 °C for 1 h and then heating at 100 °C for 2.5 h in the oven using a thermostable α-amylase aqueous solution was highly effective in liberating the arsenic species. The recoveries of iAs and dimethylarsinic acid (DMA) in NMIJ-7532a were 99.7% ± 1.6% (n = 3) and 98.1% ± 2.3% (n = 3), respectively, in comparison with the certificated values. Thus, the proposed extraction method is a green procedure that does not use any acidic, basic, or organic solvents. Moreover, this extraction method could effectively maintain the integrity of the native arsenic species of As(III), As(V), monomethylarsonate (MMA), DMA, arsenobetaine (AsB) and arsenocholine (AsC). Under the optimum extraction, chromatography and ICP-MS conditions, the limits of detection (LOD) obtained were 0.47 ng g−1, 1.67 ng g−1 and 0.80 ng g−1 for As(III), As(V) and DMA, respectively, while the limits of quantification (LOQ) achieved were 1.51 ng g−1, 5.34 ng g−1 and 2.57 ng g−1 for As(III), As(V) and DMA, respectively. Subsequently, the proposed method was successfully applied to As speciation analysis for several rice flour samples collected from contaminated areas in China.
      Citation: Separations
      PubDate: 2022-04-22
      DOI: 10.3390/separations9050105
      Issue No: Vol. 9, No. 5 (2022)
  • Separations, Vol. 9, Pages 106: Separation Abilities of Capillary
           Electrophoresis Coupled with Ion Mobility Mass Spectrometry for the
           Discrete Detection of Sequence Isomeric Peptides

    • Authors: Yury E. Glazyrin, Gleb G. Mironov, Anna S. Kichkailo, Maxim V. Berezovski
      First page: 106
      Abstract: The separation and discrete detection of isomeric sequence peptides with similar properties are important tasks for analytical science. Three different peptide isomers of 12 amino-acid residues long, containing direct and reverse regions of the alanine-valine-proline-isoleucine (AVPI) motif, were partially separated and discretely detected from their mixture using two approaches. Capillary electrophoresis enabled the separation and optical detection of the peptide sequence isomers close to the baseline. The ability to separate these sequence isomers from the mixture and discretely identify them from mass spectra has also been demonstrated by ion-mobility tandem mass spectrometry. Moreover, for the first time, capillary electrophoresis and ion-mobility mass spectrometry connected online have shown their ability for a discrete detection of the multidirectional sequence isomers.
      Citation: Separations
      PubDate: 2022-04-25
      DOI: 10.3390/separations9050106
      Issue No: Vol. 9, No. 5 (2022)
  • Separations, Vol. 9, Pages 107: Tyrosinase Inhibitory Activity of Extracts
           from Prunus persica

    • Authors: Kazuya Murata, Satomi Suzuki, Akane Miyamoto, Miki Horimoto, Suzuna Nanko, Daisuke Mori, Hiroshi Kanamaru, Yuichi Endo
      First page: 107
      Abstract: The demand for skin-whitening agents is high across the world, including Asian countries. An extensive screening using a tyrosinase inhibition assay was performed in order to discover novel plant materials. In our research program investigating a safe and effective agent, 50% ethanolic extracts prepared from discarded parts of Prunus persica were screened for in vitro tyrosinase inhibitory activity. Among the extracts tested, twig extract showed the most potent inhibitory activity: 38% inhibition at 500 µg/mL. The investigation of active compounds in twig extract found four flavanones that acted as moderate inhibitors, including (−)-prunin, persiconin, (+)-dihydrokaempferol, and (−)-naringenin. These compounds were only observed in the twig extract following preliminary quantification by HPLC, with the following concentrations: (−)-prunin, 1.8 mg/g sample; persiconin, 0.8 mg/g sample; (+)-dihydrokaempferol, 0.8 mg/g sample; (−)-naringenin, 1.7 mg/g sample. These results suggest that twig extracts can be more useful for skin-whitening compared with other parts of the plant. In addition, a new constituent of twig extract was identified, namely isoquercitrin, which suggests that twig extract can be a potent source of flavones and flavanones. Further studies on the identification of novel compounds from twig extract are now underway in our laboratory.
      Citation: Separations
      PubDate: 2022-04-26
      DOI: 10.3390/separations9050107
      Issue No: Vol. 9, No. 5 (2022)
  • Separations, Vol. 9, Pages 108: Application of Time of Flight Mass
           Spectrometry in the Identification of Dendrobium devonianum Paxt and
           Dendrobium officinale Kimura et Migo Grown in Longling Area of Yunnan,

    • Authors: Tao Lin, Xing-Lian Chen, Jing Wang, Zheng-Xu Hu, Guang-Wei Wu, Ling-Jie Sha, Long Cheng, Hong-Cheng Liu
      First page: 108
      Abstract: In this study, in order to protect the characteristic Dendrobium devonianum Paxt industry in the Longling area, and promote the healthy development of its characteristic Chinese herbal medicines in Yunnan Province, China, the identification of Dendrobium devonianum Paxt and Dendrobium officinale Kimura et Migo from Longling county was discussed using time of flight mass spectrometry. The data of 13 Dendrobium devonianum and 7 Dendrobium officinale in the Longling area were collected by TOF MS-IDA-15 MS/MS mode, and the collected data were analyzed by PCA and T-test using MarkerView software, and the difference markers were searched using the database to confirm their compound structures. In positive and negative ion modes, 3645 and 2344 peaks were detected, respectively; 64 positive ion compounds and 60 negative ion compounds, for a total of 124 compounds were identified, mainly including organic acids, polyphenols, alkaloids, amino acids and their derivatives, benzene and its derivatives, and other compounds. The score plot and loading plot analyzed by PCA show that Dendrobium devonianum and Dendrobium officinale collected in the Longling area can be effectively identified and differentiated by high-resolution mass spectrometry with the 15 different markers in positive ion mode and 17 markers in negative ion mode, respectively. The successful identification of Dendrobium devonianum and Dendrobium officinale fully demonstrates that TOF MS can be effectively used in the identification of Dendrobium and related Chinese herbal medicines with broadly application foreground.
      Citation: Separations
      PubDate: 2022-04-26
      DOI: 10.3390/separations9050108
      Issue No: Vol. 9, No. 5 (2022)
  • Separations, Vol. 9, Pages 109: Analytical Methods and Application of
           Separation Techniques in Food Science

    • Authors: Natalia Drabińska, Marta Ferreiro-González
      First page: 109
      Abstract: Food chemistry is a branch of chemistry that aims to characterize the chemical composition of food products, both qualitatively and quantitatively [...]
      Citation: Separations
      PubDate: 2022-04-28
      DOI: 10.3390/separations9050109
      Issue No: Vol. 9, No. 5 (2022)
  • Separations, Vol. 9, Pages 110: Effects and Mechanism of Fe3+ on Flotation
           Separation of Feldspar and Epidote with Sodium Oleate at Natural pH

    • Authors: Weiwei Zeng, Guofan Zhang, Qing Shi, Leming Ou
      First page: 110
      Abstract: The most common beneficiation method for feldspar is flotation with a cationic (amine) collector under acidic conditions. However, there are several disadvantages to this, such as environmental pollution and equipment corrosion. In order to resolve such problems, it is important to study the flotation of feldspar using anionic collectors under natural pH conditions. The purpose of this paper is to study the effects and mechanism of Fe3+ on flotation separation of feldspar and epidote using sodium oleate (NaOL) at a natural pH. Through flotation experiments, adsorption measurements, zeta potential testing, FTIR analysis and X-ray photoelectron spectroscopy (XPS), the mechanism of Fe3+ on the surface of feldspar and epidote is revealed, and the reason behind the difference in flotation of the two minerals is discussed. The flotation test results show that Fe3+ can significantly improve the flotation behavior of minerals when NaOL is used as a collector under natural pH, and the highest recovery rates of feldspar and epidote are 90% and 43%, respectively. Analysis of the solution and adsorption measurement results show that Fe3+ is adsorbed on the minerals′ surface in the form of Fe(OH)3, which promotes the adsorption of NaOL on the minerals’ surface through Fe(OH)3, activating the flotation of feldspar and epidote. The difference in adsorption of Fe3+ between feldspar and epidote is the reason for this difference in flotation behavior. The results of the zeta potentials show that after being treated with Fe3+, the electrostatic adsorption of NaOL displays a significant negative shift on the surface of feldspar, while there is almost no electrostatic adsorption of NaOL on the surface of Fe3+-treated epidote. FTIR analysis confirmed that the difference in the adsorption of Fe3+ and NaOL on the surface of feldspar and epidote is due to the fact that there are more active particles (metal bonds) on the surface of feldspar than on the surface of epidote, and the properties of these metal bonds can be changed by Fe3+, which allows NaOL to be more easily adsorbed on the mineral surface through –COO−. The possible adsorption form is “mineral-Fe3+–COO−“. Compared with the infrared spectrum of epidote, there is a new absorption peak at 1713.68 cm−1, which can be attributed to the C=O characteristic peak of NaOL in the infrared spectrum of Fe3+–NaOL-treated feldspar, which is why the floatability of feldspar is better than epidote. XPS confirmed that the Fe on the surface of feldspar is Fe3+ in the form of Fe(OH)3, while Fe on the surface of epidote is mainly Fe2O3 (Fe–O) contained in mineral crystals. Furthermore, there is less adsorption of Fe3+ on the surface of epidote, and this discrepancy leads to the difference in the adsorption of NaOL on the minerals’ surface, which itself leads to the difference in flotation behavior between feldspar and epidote. These findings indicate that the flotation separation of feldspar and epidote can be achieved using Fe3+ and NaOL under natural pH. This study may provide a reference for the flotation mechanism of feldspar and epidote under natural pH.
      Citation: Separations
      PubDate: 2022-04-28
      DOI: 10.3390/separations9050110
      Issue No: Vol. 9, No. 5 (2022)
  • Separations, Vol. 9, Pages 111: Preparation and Antioxidant Activities of
           Phenylethanoids from Dracocephalum heterophyllum

    • Authors: Yue Lv, Ze Wang, Qian Wu, Yan Fang, Qilan Wang, Gang Li, Jun Dang
      First page: 111
      Abstract: The health benefits of Dracocephalum heterophyllum are widely reported in traditional Tibetan medicines, but the reported chemical composition is limited, probably due to difficulties in separating and purifying compounds. In this study, antioxidative phenylethanoids were isolated from an extract of Dracocephalum heterophyllum using medium- and high-pressure liquid chromatography, coupled with on-line HPLC–1,1-diphenyl-2-picrylhydrazyl recognition. Firstly, crude samples (1.3 kg) of Dracocephalum heterophyllum were pretreated via silica gel medium-pressure liquid chromatography to yield 994.0 g of Fr2, of which 10.8 g was then pretreated via MCI GEL®CHP20P medium-pressure liquid chromatography. The resulting Fr23 and Fr25 were further separated and purified using high-pressure liquid chromatography, and yielded 8.08 mg of Fr2391, 9.76 mg of Fr2551, 16.09 mg of Fr2581, and 8.75 mg of Fr2582. Furthermore, analysis of the purity and structures of the phenylethanoids suggested that Fr2391, Fr2551, Fr2581, and Fr2582 corresponded to decaffeoylverbascoside, rosmarinic acid, acteoside, and 2′-O-acetylplantamajoside, respectively, with all being over 95% pure. Finally, the antioxidant potential of the compounds was explored based on their ability to scavenge 1,1-diphenyl-2-picrylhydrazine, as well as through molecular docking of proteins related to antioxidant pathways. Altogether, our findings revealed that the proposed method is promising for separating pure antioxidative phenylethanoids from other natural compounds.
      Citation: Separations
      PubDate: 2022-04-28
      DOI: 10.3390/separations9050111
      Issue No: Vol. 9, No. 5 (2022)
  • Separations, Vol. 9, Pages 112: Analysis of Differentially Expressed
           Proteins and Modifications Induced by Formaldehyde Using LC-MS/MS

    • Authors: Ranran Liu, Yue Han, Zhiyue Wu, Jianji Zhang, Yong Zang, Lijin Shen, Shanshan Tian, Kai Zhang
      First page: 112
      Abstract: Formaldehyde (FA) is a toxic compound that is considered to have a carcinogenic effect due to its damage to biological macromolecules. However, the influence of FA at the protein level remains to be explored. Here, we used LC-MS/MS to identify the differentially expressed proteins and modifications to proteins between FA-treated and untreated HeLa cells. Among 2021 proteins identified, 196 proteins were significantly down-regulated and 152 up-regulated. The differentially expressed proteins were further analyzed using bioinformatics tools for annotating the characterization of their localizations and functions. To evaluate the interaction of FA with proteins, we performed proteomic analysis for a mass shift of 12 Da on the side chains of lysine, cysteine and tryptophan, which are induced by FA as noticeable signals. We identified the modified proteins and sites, suggesting direct interaction between FA and proteins. Motif analysis further showed the characterization of amino acid sequences that react with FA. Cluster analysis of the modified proteins indicated that the FA-interacting networks are mostly enriched in the nuclei, ribosomes and metabolism. Our study presents the influence of FA on proteomes and modifications, offering a new insight into the mechanisms underlying FA-induced biological effects.
      Citation: Separations
      PubDate: 2022-04-29
      DOI: 10.3390/separations9050112
      Issue No: Vol. 9, No. 5 (2022)
  • Separations, Vol. 9, Pages 113: Investigation of Selective Ribavirin
           Extraction from Serum Samples Using a Monolithic Silica Disk-Packed Spin

    • Authors: Yuko Yui, Shigenori Ota, Chiaki Aoyama, Yanting Song, Makoto Tsunoda
      First page: 113
      Abstract: Ribavirin, a nucleoside analog, is used to treat chronic hepatitis C (HCV) infections. Therapeutic drug monitoring for ribavirin is useful for predicting the effect of treatment. In this study, the selective extraction of ribavirin from serum samples and the HPLC-UV detection method were investigated using a monolithic silica disk-packed spin column with phenylboronate moieties. In this study, 0.6% ammonia and 1% formic acid solutions were used as the conditioning and elution solutions, respectively, and recoveries of >90% were obtained. Ribavirin was separated on an InertSustain AQ-C18 column by isocratic elution. The mobile phase consisted of a mixture of 7 mM Na2SO4 and 60 mM H3PO4 in H2O. Linear regression curves were observed for calibrations over a concentration range of 0.25–25 µg/mL. The lower limit of detection was 0.05 µg/mL, and the lower limit of quantification was 0.1 µg/mL. The intra- and inter-day precisions were below 3.2 and 3.1%, respectively. This method can be applied to quantify ribavirin levels in human serum and may be useful for pharmacokinetic studies.
      Citation: Separations
      PubDate: 2022-04-30
      DOI: 10.3390/separations9050113
      Issue No: Vol. 9, No. 5 (2022)
  • Separations, Vol. 9, Pages 114: Chromatography in Ukraine: Development and

    • Authors: Modest Gertsiuk
      First page: 114
      Abstract: The development of chromatographic science in Ukraine is due to the widespread use of chromatography to solve practical problems. The centers of chromatographic research in Ukraine are in large cities: Kyiv, Kharkiv, Lviv, Odessa, and others. Along with the development of chromatographic research methods, analysis methods for control of food and agricultural raw materials, medicinal products, petroleum products, and determination of the environmental pollution state are created. Chromatography is used in medicine, pharmacology, biology, and other sciences.
      Citation: Separations
      PubDate: 2022-05-03
      DOI: 10.3390/separations9050114
      Issue No: Vol. 9, No. 5 (2022)
  • Separations, Vol. 9, Pages 115: Intestinal Glucuronidation, Prior to
           Hepatic Glucuronidation, Plays an Important Role in the Low Circulating
           Levels of Calycosin

    • Authors: Haodong Jiang, Huan Liu, Pei Hu, Shuoji Chen, Yaqing Ye, Chenggang Huang, Xiaoting Tian
      First page: 115
      Abstract: Calycosin is a dietary flavonoid with favorable activities, which seems to be inconsistent with its low circulating levels in vivo. To address this issue, we developed a strategy to understand calycosin distribution by integrating qualitative and quantitative analyses of calycosin and its metabolites in portal vein plasma, the liver, and systemic plasma after oral administration to rats. Consequently, 21 metabolites were characterized in total, including the first report of a reductive biotransformation and 14 new metabolites. Compared with the low levels of calycosin, calycosin glucuronides were predominant in circulation, and both the hepatic and intestinal regions contributed to the high exposure of these calycosin glucuronides. However, intestinal glucuronidation, prior to hepatic glucuronidation, plays a key role in the low circulating levels of calycosin.
      Citation: Separations
      PubDate: 2022-05-08
      DOI: 10.3390/separations9050115
      Issue No: Vol. 9, No. 5 (2022)
  • Separations, Vol. 9, Pages 116: Study of the Dissolution and Diffusion of
           Propane, Propylene and Nitrogen in Polydimethylsiloxane Membranes with
           Molecular Dynamics Simulation and Monte Carlo Simulation

    • Authors: Weibin Cai, Mingqian Wang, Gary Q. Yang, Zhijun Zhang, Yujun Wang, Jiding Li
      First page: 116
      Abstract: Volatile organic compounds (VOCs) are important sources of atmospheric pollutants on account of their high recycling value. The membrane of dense silicone rubber polydimethylsiloxane (PDMS) has wide-ranging prospects for the separation and recovery of VOCs. In this study, PDMS membrane body models were established in BIOVIA Materials Studio (MS) to simulate VOCs with C3/N2 gases, and to study the structure of PDMS membranes and the dissolution and diffusion process of gas in the membranes. The free volume fraction (FFV), cohesive energy density (CED), radial distribution function (RDF), diffusion coefficient and solubility coefficient of C3H8, C3H6 and N2 in PDMS membranes were calculated, and the permeability coefficients were calculated according to these values. At the same time, the effects of temperature and mixed gas on the dissolution and diffusion of C3/N2 in PDMS membranes were investigated. The results show that the mass transfer process of C3 in PDMS membranes is mainly controlled by the dissolution process, while that of N2 is mainly controlled by the diffusion process. In a C3/N2 mixed gas system, there is a synergistic relationship between gases in the diffusion process, while there is competitive adsorption in the dissolution process. With an increase in temperature, the diffusion coefficients of the three gases in PDMS gradually increase, the solubility coefficients gradually decrease, and the overall permeability selectivity coefficients of the gases gradually decrease. Therefore, low-temperature conditions are more conducive to the separation of C3/N2 in PDMS membranes. The simulation results of the permeability selectivity coefficients of pure C3 and N2 in PDMS are similar to the experimental results, and the relationship between the micro- and macro-transport properties of PDMS membranes can be better understood through molecular simulation.
      Citation: Separations
      PubDate: 2022-05-10
      DOI: 10.3390/separations9050116
      Issue No: Vol. 9, No. 5 (2022)
  • Separations, Vol. 9, Pages 117: Antioxidant and Antibacterial Activities
           of a Purified Polysaccharide Extracted from Ceratonia siliqua L. and Its
           Involvement in the Enhancement Performance of Whipped Cream

    • Authors: Ameni Dammak, Sirine Ben Slima, Marco D. R. Gomes da Silva, Riadh Ben Salah, Awad M. Aljuaid, Wafik Hachicha, Mohamed Bouaziz
      First page: 117
      Abstract: The main objective discussed in this research was to determine the structural characteristics of carob kibble water-soluble polysaccharide (KWSP), extracted from Ceratonia siliqua L., and to assess its in vitro antioxidant activities, as well as its effect on whipped cream. The results obtained through 13C, 1H, and the hetero-nuclear single quantum coherence (HSQC) nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FT-IR) analysis indicated that KWSP had the characteristic bands of polysaccharides. Thin layer chromatography (TLC) and high performance liquid chromatography (HPLC) suggested that KWSP is a hetero-polysaccharide composed of glucose and fructose, with an average molecular weight (Mw) amounting to 65 KDa. In addition, KWSP showed a good water holding capacity (WHC), a good oil holding capacity (OHC), and an emulsification stability, rated as 3.14 ± 0.05 g/g, 0.87 ± 0.02 g/g, and 71 ± 0.01%, respectively. The antioxidant activity of KWSP was investigated in vitro, demonstrating important DPPH and ABTS⋅+ radical scavenging activities and a good total antioxidant capacity. KWSP exhibited antibacterial activity against Listeria monocytogenes, Staphylococcus aureus, and Salmonella enterica. On the other hand, the incorporation of KWSP in whipped cream was investigated, to enhance its antioxidant capacity and consequently to extend its expiration date. Moreover, KWSP reduces the formation of conjugated dienes and trienes in cream fat.
      Citation: Separations
      PubDate: 2022-05-10
      DOI: 10.3390/separations9050117
      Issue No: Vol. 9, No. 5 (2022)
  • Separations, Vol. 9, Pages 118: Enhanced Sample Throughput Capillary Zone
           Electrophoresis with UV Detection in Hydrodynamically Closed System for
           Determination of Ibuprofen

    • Authors: Ondrej Stefanik, Andrea Horniakova, Ivana Cizmarova, Michaela Matuskova, Veronika Mikusova, Peter Mikus, Juraj Piestansky
      First page: 118
      Abstract: A simple analytical approach based on capillary zone electrophoresis with ultraviolet detection and repeated sample injection strategy (applied in a hydrodynamically closed separation system for the first time) was developed for the determination of ibuprofen (IBU) in commercially available pharmaceutical preparations. The proposed method was characterized by significantly increased sample throughput and favorable validation parameters, highly demanded in routine quality control laboratories. The limit of detection was predicted at the concentration level of 0.31 µg/mL. Intra-day precision expressed as the relative standard deviation of IBU concentration ranged from 1.9 to 5.6%, and corresponding intra-day accuracy expressed as the relative error was in the interval of 87.1–106.5%. Inter-day precision was in the range of 2.6–15.0%, and inter-day accuracy was 94.9–102.7%. The developed method was able to quantify IBU in complex pharmaceutical matrices represented by commercially available tablets and oral suspension. The determined contents of IBU in the tested dosage forms were in good agreement with the manufacturer’s declaration. The analytical performance of the developed method was evaluated according to the innovative RGB Additive Color Model strategy. It was demonstrated that the proposed method is characterized by very good analytical performance parameters, safety and eco-friendliness, and practical effectiveness.
      Citation: Separations
      PubDate: 2022-05-11
      DOI: 10.3390/separations9050118
      Issue No: Vol. 9, No. 5 (2022)
  • Separations, Vol. 9, Pages 119: Profiling the Volatile and Non-Volatile
           Compounds along with the Antioxidant Properties of Malted Barley

    • Authors: Fouad El Mansouri, Hammadi El Farissi, Francesco Cacciola, Joaquim C. G. Esteves da Silva, Miguel Palma Lovillo, Yassine Oulad El Majdoub, Emanuela Trovato, Luigi Mondello, Mohamed Khaddor, Jamal Brigui
      First page: 119
      Abstract: In this work, the stability of antioxidant compounds in malting barley seeds before and after the production of the final products is reported. In this reflection, the findings revealed that the process of fermentation had a significant impact on antioxidant activity. In vitro, antioxidant capacities were evaluated using DPPH free radical scavenging assay. The results obtained from the spectrophotometric analysis showed that the lowest inhibition value was observed in the samples that were obtained by the classical fermentation process (ABC) and the samples of non-alcoholic beer obtained by the thermal process (NABT), with free radical inhibition capacity values of 8.50% and 5.50%, respectively. The samples of hopped wort (HW) and malted barley seeds extract (BSE) showed very high antioxidant activity with free radical inhibition capacity of 14% and 12.60%, respectively. The obtained extracts were analyzed by gas chromatography and high-performance liquid chromatography, both combined with mass spectrometry detection (GC–MS, HPLC–MS). GC–MS analysis of the SPME extraction showed the presence of 29 compounds with isopentyl alcohol in major concentration (18.19%) in the alcoholic beer; on the other hand, the HPLC–DAD–ESI/MS analysis of the ethyl acetate extract showed the presence of 13 phenolic compounds. Interestingly, the degradation of 3-Hydroxyphloretin 2′-O-glucoside in the final products of the non-alcoholic beers was found. Finally, the FTIR analysis was also employed in order to detect the type of efficient groups present in the extracts.
      Citation: Separations
      PubDate: 2022-05-12
      DOI: 10.3390/separations9050119
      Issue No: Vol. 9, No. 5 (2022)
  • Separations, Vol. 9, Pages 120: Separation of Microalgae by a Dynamic Bed
           of Magnetite-Containing Gel in the Application of a Magnetic Field

    • Authors: Takehiro Washino, Mikihide Demura, Shintaro Morisada, Keisuke Ohto, Hidetaka Kawakita
      First page: 120
      Abstract: Microalgae are now known as potential microorganisms in the production of chemicals, fuel, and food. Since microalgae live in the sea and the river, they need to be harvested and separated and cultured for further usage. In this study, to separate microalgae, a bed of magnetite-containing gel (Mag gel, 190 µm) was packed in the column by the application of a magnetic field for the separative elution of injected microalgae (including mainly four species), cultured at Saga University in Japan. The applied magnetic field was set at a constant and dynamic-convex manner. At a constant magnetic field of 0.4–1.1 T, the elution percentage of the microalgae at less than 5 µm was 30–50%. At 1.1 T, the larger-sized microalgae were eluted at a percentage of 20%, resulting in the structural change of the bed by the applied magnetic field. In a convex-like change of the magnetic field at 1.1 T ⇄ 0.4 T, the smaller-sized microalgae were selectively eluted, whereas at 1.1 T ⇄ 0.8 T, the larger-sized microalgae were eluted. Dynamic convex-like changes by the magnetic field selectively eluted the microalgae, leading to the separation and the extraction of potential microalgae.
      Citation: Separations
      PubDate: 2022-05-12
      DOI: 10.3390/separations9050120
      Issue No: Vol. 9, No. 5 (2022)
  • Separations, Vol. 9, Pages 121: A Fast Method for the Simultaneous
           Analysis of 26 Beta-Agonists in Swine Muscle with a Multi-Functional
           Filter by Ultra-High Performance Liquid Chromatography-Tandem Mass

    • Authors: Lin Zhang, Qi Jia, Guangqin Liao, Yongzhong Qian, Jing Qiu
      First page: 121
      Abstract: A rapid and simplified sample preparation method was developed for the simultaneous determination of 26 beta-agonists in swine muscle using a multi-functional filter (MFF) based on quick, easy, cheap, effective, rugged, and safe methods (QuEChERS). MFF integrated the cleanup and filter procedures, thereby significantly improving the efficiency of sample preparation compared with traditional solid-phase extraction. The sample was processed via enzymatic hydrolysis, purified with the optimized MFF containing 150 mg magnesium sulfate, 50 mg PSA, and 50 mg C18, and then analyzed using ultra-high performance liquid chromatography-tandem mass spectrometry. All procedures can be completed in 6.5 h. Good linearity (R2 > 0.99) was detected in all analytes. The recoveries ranged from 71.2% to 118.6%, with relative standard deviations (RSDs) of less than 18.37% in all spiked concentrations. The limits of detection (LOD) and the limits of quantitation (LOQ) were 0.01–0.10 and 0.10–0.50 μg/kg, respectively. The decision limit (CCα) and detection capacity (CCβ) values fluctuated in the range of 3.44–25.71 and 6.38–51.21 μg/kg, respectively. This method is a good alternative for detecting beta-agonist residues in swine muscle and can be successfully applied to the national risk monitoring of agro-product quality and safety in China.
      Citation: Separations
      PubDate: 2022-05-13
      DOI: 10.3390/separations9050121
      Issue No: Vol. 9, No. 5 (2022)
  • Separations, Vol. 9, Pages 122: Numerical Simulation of Dense Solid-Liquid
           Mixing in Stirred Vessel with Improved Dual Axial Impeller

    • Authors: Xia Xiong, Zuohua Liu, Changyuan Tao, Yundong Wang, Fangqin Cheng
      First page: 122
      Abstract: Computational fluid dynamics (CFDs) were adopted in order to investigate the solid suspending process in a dense solid–liquid system (with a solid volume fraction of 30%), agitated by a traditional dual axial impeller and a modified dual axial impeller, otherwise known as a dual triple blade impeller (DTBI) and a dual rigid-flexible triple blade impeller (DRFTBI), respectively. The effects of rotational speed, connection strap length/width, and off-bottom clearance on the solid distribution were investigated. The results show that the proportion of solid concentration larger than 0.4 in the DTBI system was 26.56 times of that in the DRFTBI system. This indicates that the DRFTBI system can strengthen the solid suspension and decrease the solid accumulation in the bottom of the tank. Furthermore, the velocity and turbulent kinetic energy in the DRFTBI system were promoted. In addition, for an optimal selection, the optimum length of connection strap was 1.2 H1, the optimum range of connection strap width was D/7–D/8, and the off-bottom clearance selected as T/4 was better.
      Citation: Separations
      PubDate: 2022-05-16
      DOI: 10.3390/separations9050122
      Issue No: Vol. 9, No. 5 (2022)
  • Separations, Vol. 9, Pages 123: The 20-Year Jubilee of the Interdivisional
           Group of Separation Science of the Italian Chemical Society

    • Authors: Danilo Corradini, Luigi Mondello
      First page: 123
      Abstract: This paper illustrates the origin, mission, organization and main activities of the Interdivisional Group of Separation Science (Gruppo Interdivisionale di Scienza delle Separazioni, GISS) of the Italian Chemical Society in occasion of the twentieth anniversary of this organization, whose mission is to promote and disseminate knowledge on all aspects of separation science and to facilitate strong peer-to-peer relationships. GISS originates from a discussion group, also belonging to the Italian Chemical Society (SCI), having similar finality and the same promoter (the Italian pioneer of Chromatography Prof. Arnaldo Liberti), but less extended scientific interests than the GISS, since it was mainly focused on liquid and gas chromatography. The interests of the GISS span theoretical and practical aspects of separation science and cover all key topics requiring high-performance separation techniques to carry out advanced investigations and/or solve challenging analytical problems. The panoramic view of the GISS includes a synthetic review of the main activities carried out since its foundation, which comprises fast-track discussion meetings, participation, promotion and/or organization of national and international congresses, sponsorship of participation grants for young trainees and Ph.D. students, recognition of scientists who have made and continue to make an outstanding contribution to separation science, as well as young scientists who have evidenced their attitude to carry out significant studies in the field of separation science.
      Citation: Separations
      PubDate: 2022-05-16
      DOI: 10.3390/separations9050123
      Issue No: Vol. 9, No. 5 (2022)
  • Separations, Vol. 9, Pages 124: Influence and Mechanism of Polar Solvents
           on the Retention Time of Short-Chain Fatty Acids in Gas Chromatography

    • Authors: Mu Ren, Narantsogt Natsagdorj, Na Shun
      First page: 124
      Abstract: Short-chain fatty acids (SCFAs), produced by microbes when dietary fiber ferments in the colon, are one of the most studied microbial products despite their volatility and complex matrices, which make analysis challenging. In the current study, we sought to address research gaps by exploring the commonalities and differences between the retention time changes for SCFAs in polar solvents. In one such solvent, dimethyl sulfoxide (DMSO), the retention time of the SCFA acetic acid shows a linear positive correlation with the equal volume increase in the DMSO solvent. We used gas chromatography–mass spectrometry to analyze the retention times of mixed solutions of formic acid, acetic acid, butyric acid, valeric acid, and toluene in the solvents DMSO and water and found that only the retention times of formic acid and acetic acid changed. We further compared the effect of three solvents with similar polarities, DMSO, N-methylpyrrolidone (NMP), and dimethylformamide (DMF), on the retention time of acetic acid and found that it increased in the DMSO–water solution more than in the NMP–water solution and remained unchanged in the DMF–water solution. This finding is consistent with quantum chemical calculations showing that the strength of the hydrogen bond between DMSO and acetic acid is greater than between NMP and acetic acid. Taken together, the chromatographic results and quantum chemical calculations indicate that, in all three solvents, the portion of the molecule with the smallest negative electrostatic potential (red) has high electron density and can easily donate electrons, forming a hydrogen bond with acetic acid. However, the portion with the largest positive electrostatic potential (blue) forms a bond with polyethylene glycol, a column stationary solution with a strong dipole moment, and is adsorbed on the stationary solution in the direction of the dipole moment. Therefore, the retention times of formic acid and acetic acid change under the combined influence of a series of complex intermolecular forces. In the chromatographic column, the outflow rate of DMF is higher than that of acetic acid, and the force of the hydrogen bond between DMF and acetic acid cannot overcome the outflow resistance of acetic acid, so the retention time of the acetic acid in the DMF–water solution does not change. The retention times of butyric acid and valeric acid are unchanged in aprotic polar solvents for the same reason.
      Citation: Separations
      PubDate: 2022-05-16
      DOI: 10.3390/separations9050124
      Issue No: Vol. 9, No. 5 (2022)
  • Separations, Vol. 9, Pages 125: Benefits of a Mixed-Mode Stationary Phase
           to Address the Challenging Purification of an Industrially Relevant
           Peptide: A Proof-of-Concept Study

    • Authors: Giulio Lievore, Desiree Bozza, Martina Catani, Alberto Cavazzini, Tatiana Chenet, Luisa Pasti, Lucia Ferrazzano, Walter Cabri, Marco Macis, Antonio Ricci, Chiara De Luca, Simona Felletti
      First page: 125
      Abstract: Peptides are a class of biomolecules with a great potential from the therapeutic point of view, because of their unique biological properties. Industrially, the production stategies adopted produce both the target peptide and a series of impurities that must be removed. Preparative chromatography is the technique of choice for the large-scale purification of biomolecules, generally performed in reversed-phase mode, using hydrophobic adsorbents (e.g., C8 stationary phases). A promising and innovative alternative is represented by mixed-mode columns, which bear two different ligands on the particle surface, exploiting two different retention mechanisms to improve the separation. This work represents a proof-of-concept study focused on the comparison of a hydrophobic adsorbent and a mixed-mode one (bearing both hydrophobic groups and charged ones) for the purification of a crude peptide mixture. Thanks to more-favourable thermodynamics, it was found that, when collecting the whole peak excluding fractions of the peak tail, the mixed-mode column led to an increase in the recovery of roughly +15%, together with a slight improvement in purity at the same time, with respect to the traditional hydrophobic column. In addition, if the whole peak, including the tail, is collected, the performance of the two columns are similar in terms of purity and recovery, but the pepetide elutes as a narrower peak with the mixed mode. This leads to a collection pool showing a much-higher peptide concentration and to lower solvent volumes needed, which is a beneficial achievement when targeting more sustainable processes. These results are very advantageous from the industrial viewpoint, because they also involve a decrease in the peptide amount contained in the peak tail, which must be reprocessed again to satisfy purity requirements.
      Citation: Separations
      PubDate: 2022-05-17
      DOI: 10.3390/separations9050125
      Issue No: Vol. 9, No. 5 (2022)
  • Separations, Vol. 9, Pages 126: Exploration of Fulvic Acid as a Co-Former
           in Crystal Engineering

    • Authors: Kattamanchi Gnananath, Kolli Prabhanjan Kumar, Yejella Rajendra Prasad, Kalakonda Sri Nataraj, Mohamad Taleuzzaman, Mohammad Javed Ansari, Mohd. Aamir Mirza
      First page: 126
      Abstract: The aim of the project was to investigate Peat-derived Fulvic acid for its propensity to form co-crystals with quercetin and curcumin and characterize it by using different analytical techniques. The formation of co-crystals generally enhances water solubility and the overall bioavailability of molecules. Co-crystals were synthesized using a 1:1 stoichiometric ratio of fulvic acid with quercetin and curcumin, respectively, using solvent crystallization techniques taking tetrahydrofuran and water in a 1:1 v/v ratio. The co-crystals were characterized by spectroscopic methods, FTIR and Differential scanning calorimetry. Further confirmation was made by morphological studies using SEM. A structural analysis was also carried out, using 13C solid-state NMR analysis. The studies confirmed the formation of semi crystalline forms. Furthermore, the saturation solubility displayed the enhancement in solubility of up to 10, 5-folds for Quercetin and Curcumin, respectively. The in vitro dissolution results showed that T50% was achieved within 30 min for both the drugs. The literature supports that the nutraceutical co-crystals offer advantages, particularly in the improvement of biopharmaceutical properties and addressing the challenges of the lab and manufacturing scale process. Both the semi crystalline powders exhibited enhanced solubility and a better dissolution profile.
      Citation: Separations
      PubDate: 2022-05-18
      DOI: 10.3390/separations9050126
      Issue No: Vol. 9, No. 5 (2022)
  • Separations, Vol. 9, Pages 127: Antiallergic Properties of Biflavonoids
           Isolated from the Flowers of Mesua ferrea Linn.

    • Authors: Yoshiaki Manse, Yusuke Sakamoto, Taiki Miyachi, Mitsuyo Nire, Yoshinori Hashimoto, Saowanee Chaipech, Yutana Pongpiriyadacha, Toshio Morikawa
      First page: 127
      Abstract: The methanolic extract from the flowers of Mesua ferrea Linn. (Calophyllaceae) showed significant hyaluronidase inhibitory activity. Following a bioassay-guided separation of the extract, two biflavonoids, viz., mesuaferrone-A (1) and mesuaferrone-B (2), were isolated, along with ten flavonoids (3–12), two xanthones (13 and 14), three triterpenes (15–17), a phenylpropanoid (18), and five aromatics (19–24). Among the isolates, 1 and 2 (IC50 = 51.1 µM and 54.7 µM, respectively) exhibited hyaluronidase inhibitory activity equivalent to that of the commercially available antiallergic agents disodium cromoglycate (64.8 μM) and ketotifen fumarate (76.5 μM). These biflavonoids (1 and 2) are 8-8″ linked dimers that are composed of naringenin (1a) or apigenin (3), with their corresponding monomers lacking inhibitory activity (IC50 > 300 μM). In addition, 1 and 2 (IC50 = 49.4 µM and 49.2 µM, respectively) inhibited the release of β-hexosaminidase, which is a marker of antigen-IgE-mediated degranulation, in rat basophilic leukemia (RBL-2H3) cells. These inhibitory activities were more potent than those of the antiallergic agents tranilast and ketotifen fumarate (IC50 = 282 μM and 158 μM, respectively), as well as one of the corresponding monomers (1a; IC50 > 100 μM). Nonetheless, these effects were weaker than those of the other monomer (3; IC50 = 6.1 μM).
      Citation: Separations
      PubDate: 2022-05-18
      DOI: 10.3390/separations9050127
      Issue No: Vol. 9, No. 5 (2022)
  • Separations, Vol. 9, Pages 128: Anti-Osteoporotic Effect of
           Viscozyme-Assisted Polysaccharide Extracts from Portulaca oleracea L. on
           H2O2-Treated MC3T3-E1 Cells and Zebrafish

    • Authors: Yunhua Fu, Xuan Hu, Dongyue Zhou, Xue Li, Xingyu Tao, Di Yang, Fei Zheng, Yulin Dai, Hao Yue
      First page: 128
      Abstract: This study aims to screen and characterize the protective effect of polysaccharides from Portulaca oleracea L. (POP) against H2O2-stimulated osteoblast apoptosis in vivo and in vitro. The enzymes viscozyme, celluclast, α-amylase, and β-glucanase were used to extract POPs. Among all enzyme-assisted POPs, the first participating fraction of viscozyme extract POP (VPOP1) exhibited the highest antioxidant activity. Hoechst 33342 and acridine orange/ethidium bromide staining and flow cytometry of MC3T3 cells revealed that VPOP1 inhibited apoptosis in a dose-dependent manner. Moreover, VPOP1 increased the expression levels of heme oxygenase-1 (HO-1) and NADPH quinine oxidoreductase 1 (NQO1) and decreased the expression levels of nuclear factor (erythroid-derived 2)-like 2 (Nrf2) and Kelch-like ECH-associated protein 1 (Keap1) in H2O2-induced cells compared with their controls. The results of an in vivo experiment show that VPOP1 significantly reduced reactive oxygen species generation and lipid peroxidation in zebrafish at 72 h post-fertilization and promoted bone growth at 9 days post-fertilization. Furthermore, VPOP1 was identified via 1-phenyl-3-methyl-5-pyrazolone derivatization as an acidic heteropolysaccharide comprising mannose and possessing a molecular weight of approximately 7.6 kDa. Collectively, VPOP1 was selected as a potential anti-osteoporotic functional food because of its protective activity against H2O2-induced damage in vitro and in vivo.
      Citation: Separations
      PubDate: 2022-05-20
      DOI: 10.3390/separations9050128
      Issue No: Vol. 9, No. 5 (2022)
  • Separations, Vol. 9, Pages 129: A Novel Centrifugal Filtration Device

    • Authors: Chia-Cheng Lin, Jung-Ming Wu
      First page: 129
      Abstract: In the proposed centrifugal filtration device, a filter is mounted in the center of the centrifugal chamber. The particles move towards the centrifuge wall away from the filter under centrifugal force, so a filtration cake is unlikely to accumulate here. The working fluid is injected continuously, so the feed pressure is higher than the discharge pressure, which compels the light-phase fluid to leave through the filter as filtrate. The filtrate flux rate and the movement of particles in the centrifugal chamber of the proposed filtration device were investigated using different powder particle sizes, concentrations of working fluid, centrifugal chamber rotation speeds, and filters. With a higher centrifugal chamber rotation speed, the centrifugal force acting on the particles in the centrifugal chamber was stronger, and the particles were less likely to adhere to the central filter; hence, a larger amount of filtrate was produced.
      Citation: Separations
      PubDate: 2022-05-21
      DOI: 10.3390/separations9050129
      Issue No: Vol. 9, No. 5 (2022)
  • Separations, Vol. 9, Pages 130: Investigation of Molecular Mean Free Path,
           Molecular Kinetic Energy, and Molecular Polarity Affecting Knudsen
           Diffusivity along Pore Channels

    • Authors: Bin Xu, Haotian Qin, Lu Chen
      First page: 130
      Abstract: The effective purification of corrosive gases at the cathode air stream side is essential for proton exchange membrane fuel cells’ performance in real-world applications. Gas molecular diffusion depth along the pore channel is a sufficient parameter that determines the effectiveness of the porous purification media. The collision between gas molecules and pore surfaces is the crucial determinant of the diffusion depth. An analytical model was developed to predict the gas molecular diffusion depth in the pore channels. Two different crystal sizes of UiO-66 were synthesized to validate against the model result and empirically determine the diffusion depths. The parametric effects of the mean free path, molecular kinetic energy, and molecular polarity on molecular diffusivity were assessed. A smaller molecular mean free path and greater molecular kinetic energy were favorable for larger diffusion depth, owing to the fewer collisions and enhanced bounces after collisions. Greater molecular polarity led to shorter diffusion depth due to the enhanced van der Waals force between molecules and pore surfaces.
      Citation: Separations
      PubDate: 2022-05-21
      DOI: 10.3390/separations9050130
      Issue No: Vol. 9, No. 5 (2022)
  • Separations, Vol. 9, Pages 131: Assessing the Condition of Complex
           Poly-Material Artworks by Py-GC-MS: The Study of Cellulose Acetate-Based
           Animation Cels

    • Authors: Francesca Caterina Izzo, Henk Van Keulen, Alessandra Carrieri
      First page: 131
      Abstract: The material composition of a group of Rodovetri, hand-painted animation cels, made in the 1950s and 1960s for Italian television, has been determined by Flash Py-GC-MS, Thermally assisted Hydrolysis and Methylation-(Py-)GC-MS and GC-MS investigations, where, for the pyrolysis applications, the pyrolyzer is connected septum-less to the GC inlet. The condition of the selected animation cels was generally poor (yellowing, exudation, warping, cracking). The cels are made of plasticized cellulose acetate (CA) and decorated with alkyd paint. Exudating plasticizers from the CA support migrated into the paint; this has softened the paint layers and made the cels stick together. CA is known to be very unstable and easily subjected to degradation, which cannot be reversed, only slowed down by preventive conservation. Most of the cels are plasticized with bis(2-methoxyethyl) phthalate (DMEP) and triphenyl phosphate (TPP). The research shows a relationship between the degradation of CA and the presence of TPP and DMEP.
      Citation: Separations
      PubDate: 2022-05-23
      DOI: 10.3390/separations9050131
      Issue No: Vol. 9, No. 5 (2022)
  • Separations, Vol. 9, Pages 132: Simultaneous Determination of Fenchone and
           Trans-Anethole in Essential Oils and Methanolic Extracts of Foeniculum
           vulgare Mill. Fruits Obtained from Different Geographical Regions Using
           GC-MS Approach

    • Authors: Wasim Ahmad, Mohd Amir, Syed Rizwan Ahamad, Prawez Alam, Sultan Alshehri, Mohammed M. Ghoneim, Shadma Wahab, Faiyaz Shakeel
      First page: 132
      Abstract: The gas chromatography–mass spectrometry (GC-MS) approach is established for the simultaneous determination of fenchone (FCO) and trans-anethole (TOH) in the essential oils and methanolic extracts of fennel (Foeniculum vulgare Mill.) fruits obtained from India (IND), Pakistan (PAK), and Saudi Arabia (SA). The simultaneous determination of FCO and TOH was performed via Agilent 190914S HP–5MS fused-silica capillary column (30 m × 250 µm ID, 0.25 µm film thickness). The proposed GC-MS approach was linear in the range of 0.10–50 µg/g for FCO and TOH. FCO’s detection (LOD) and quantification (LOQ) limits were calculated to be 0.04 and 0.12 µg/g, respectively. The LOD and LOQ values for TOH, on the other hand, were calculated to be 0.05 and 0.15 µg/g, respectively. In addition, the proposed GC-MS approach was accurate and precise for the simultaneous determination of FCO and TOH. The amount of FCO in essential oils of F. vulgare was computed as 0.021, 0.034, and 0.029 mg/g in the samples obtained from IND, PAK, and SA, respectively. The amount of TOH in the essential oils of F. vulgare was computed as 7.40, 14.8, and 10.2 mg/g in the samples obtained from IND, PAK, and SA, respectively. However, the amount of FCO in the methanolic extract of F. vulgare was estimated as 0.031, 0.021, and 0.057 mg/g in the samples obtained from IND, PAK, and SA, respectively. On the other hand, the amount of TOH in the methanolic extract of F. vulgare was estimated as 0.440, 0.498, and 1.74 mg/g in the samples obtained from IND, PAK, and SA, respectively. These findings suggested that the proposed GC-MS approach might be used to simultaneously determine the FCO and TOH in a variety of essential oils and plant extracts.
      Citation: Separations
      PubDate: 2022-05-23
      DOI: 10.3390/separations9050132
      Issue No: Vol. 9, No. 5 (2022)
  • Separations, Vol. 9, Pages 133: Molecularly Imprinted Polymers: Selective
           Extraction Materials for Sample Preparation

    • Authors: Antonio Martín-Esteban
      First page: 133
      Abstract: Highly developed analytical instrumentation (i.e., chromatographic techniques coupled to mass spectrometry) is now available in most analytical laboratories; thus, it is possible to determine any kind of organic compound [...]
      Citation: Separations
      PubDate: 2022-05-23
      DOI: 10.3390/separations9050133
      Issue No: Vol. 9, No. 5 (2022)
  • Separations, Vol. 9, Pages 83: Simultaneous Determination of Levamisole,
           Mebendazole, and the Two Metabolite Residues of Mebendazole in Poultry
           Eggs by High-Performance Liquid Chromatography–Tandem Mass

    • Authors: Lan Chen, Zhaoyuan He, Peiyang Zhang, Yawen Guo, Yang Lu, Yayun Tang, Jinyuan Chen, Kaizhou Xie
      First page: 83
      Abstract: The quantitative determination of levamisole (LMS), mebendazole (MBZ), and the two metabolites of MBZ, 5-hydroxymebendazole (HMBZ) and 2-amino-5-benzoylbenzimidazole (AMBZ), in poultry eggs (hen, duck, and goose) was achieved with high-performance liquid chromatography–tandem triple quadrupole mass spectrometry (HPLC–MS/MS). Samples were pretreated by liquid–liquid extraction and solid-phase extraction (LLE–SPE) to extract the target compounds, and an Oasis MCX SPE column was used for purification. Determination was performed on an Xbridge C18 column with 0.1% formic acid aqueous solution and acetonitrile as mobile phases. LMS, MBZ, HMBZ, and AMBZ were detected in a triple-quadrupole mass spectrometer with ESI in positive mode and quantified with an external standard. In blank eggs, the target analyte concentrations were within the limits of quantification (LOQs)—25 μg/kg (LMS) and 150 μg/kg (MBZ, HMBZ, and AMBZ)—and the matrix-matched calibration curves had good linearity (R2 ≥ 0.9990). In the same concentration range, the average recoveries of the target analytes were 85.98–97.38% (n = 6); the relative standard deviation (RSD), intraday RSD, and interday RSD ranged from 2.06 to 4.22%, 1.40 to 5.85%, and 2.34 to 6.32%, respectively. The limits of detection (LODs) ranged from 0.03 to 0.33 µg/kg, and the LOQs ranged from 0.08 to 1.00 µg/kg. Experimental verification showed that the HPLC–MS/MS method exhibited high specificity and sensitivity for quantitative analyses of egg samples. This study provides a rapid, efficient, and sensitive method for the simultaneous detection of LMS, MBZ, HMBZ, and AMBZ residues in foods of animal origin.
      Citation: Separations
      PubDate: 2022-03-24
      DOI: 10.3390/separations9040083
      Issue No: Vol. 9, No. 4 (2022)
  • Separations, Vol. 9, Pages 84: Determination of Menbutone: Development and
           Validation of a Sensitive HPLC Assay according to the European Medicines
           Agency Guideline

    • Authors: Cristina López, Raquel Díez, José M. Rodríguez, Matilde Sierra, Juan J. García, Nélida Fernández, M. José Diez, Ana M. Sahagún
      First page: 84
      Abstract: Menbutone is often used to stimulate the hepato-digestive activity in case of digestive disorders and hepatic insufficiency in different species (cattle, sheep, goats, pigs, horses, dogs) because it has choleretic and cholagogue effects and increases gastric and pancreatic juices. The objective was to develop and validate an HPLC method to quantify menbutone in sheep plasma using sparfloxacin as internal standard. The HPLC mobile phase consisted of acetonitrile:monopotassium phosphate solution. The method was validated according to EMA guideline (EMEA/CHMP/EWP/192217/2009). Mean retention times of menbutone and sparfloxacin were 4.5 and 2.2 min, respectively. The method met all specifications of the EMA guideline, being selective and linear in the range of 0.2–100 µg/mL (R2 ≥ 0.99). The within-run precision range was 0.19–8.21%, with an accuracy of 102.99–119.52% for the lower limit of quantitation (LLOQ). For the other values (LOW, MED, HIGH) the precision range was 0.01–4.77%, with an accuracy of 85.17–109.67%. The LLOQ was 0.2 µg/mL, and no interference from the biological matrix was found. Stability of menbutone in the biological matrix at different storage conditions was also demonstrated. Thus, the method can be used to determine menbutone concentrations in plasma sheep in different types of studies.
      Citation: Separations
      PubDate: 2022-03-27
      DOI: 10.3390/separations9040084
      Issue No: Vol. 9, No. 4 (2022)
  • Separations, Vol. 9, Pages 85: Simultaneous Quantification of 17
           Cannabinoids in Cannabis Inflorescence by Liquid Chromatography-Mass

    • Authors: Amitha K. Hewavitharana, Francine Gloerfelt-Tarp, Matthew Nolan, Bronwyn J. Barkla, Sarah Purdy, Tobias Kretzschmar
      First page: 85
      Abstract: With an increasing appreciation for the unique pharmacological properties associated with distinct, individual cannabinoids of Cannabis sativa, there is demand for accurate and reliable quantification for a growing number of them. Although recent methods are based on highly selective chromatography-mass spectrometry technology, most are limited to a few cannabinoids, while relying on unnecessarily sophisticated and expensive ultra-high performance liquid chromatography and tandem mass spectrometry. Here we report an optimised, simple extraction method followed by a reliable and simple high performance liquid chromatography method for separation. The detection is performed using a time-of-flight mass spectrometer that is available in most natural products research laboratories. Due to the simplicity of instrumentation, and the robustness resulting from a high resolution in the chromatography of isobaric cannabinoids, the method is well suited for routine phytocannabinoid analysis for a range of applications. The method was validated in terms of detection and quantification limits, repeatability, and recoveries for a total of 17 cannabinoids: detection limits were in the range 11–520 pg when using a 1 µL sample injection volume, and the recovery percentages ranged from 85% to 108%. The validated method was subsequently applied to determine cannabinoid composition in the inflorescences of several medicinal Cannabis sativa varieties.
      Citation: Separations
      PubDate: 2022-03-28
      DOI: 10.3390/separations9040085
      Issue No: Vol. 9, No. 4 (2022)
  • Separations, Vol. 9, Pages 86: Proteomic and Biochemical Analysis of
           Extracellular Vesicles Isolated from Blood Serum of Patients with Melanoma

    • Authors: Kristiina Kurg, Anu Planken, Reet Kurg
      First page: 86
      Abstract: Background: Malignant melanoma is the most serious type of skin cancer with the highest mortality rate. Extracellular vesicles (EVs) have potential as new tumor markers that could be used as diagnostic and prognostic markers for early detection of melanoma. Methods: EVs were purified from the blood serum of melanoma patients using two methods—ultracentrifugation and PEG precipitation—and analyzed by mass spectrometry and immunoblot. Results: We identified a total of 585 unique proteins; 334 proteins were detected in PEG-precipitated samples and 515 in UC-purified EVs. EVs purified from patients varied in their size and concentration in different individuals. EVs obtained from stage II and III patients were, on average, smaller and more abundant than others. Detailed analysis of three potential biomarkers—SERPINA3, LGALS3BP, and gelsolin—revealed that the expression of SERPINA3 and LGALS3BP was higher in melanoma patients than healthy controls, while gelsolin exhibited higher expression in healthy controls. Conclusion: We suggest that all three proteins might have potential to be used as biomarkers, but a number of issues, such as purification of EVs, standardization, and validation of methods suitable for everyday clinical settings, still need to be addressed.
      Citation: Separations
      PubDate: 2022-03-29
      DOI: 10.3390/separations9040086
      Issue No: Vol. 9, No. 4 (2022)
  • Separations, Vol. 9, Pages 87: Extraction and Characterization of
           Flavanol-Rich Nutraceuticals Based on High-Performance Liquid

    • Authors: Oscar Vidal-Casanella, Kevin Arias-Alpizar, Oscar Núñez, Javier Saurina
      First page: 87
      Abstract: Flavanols are a class of polyphenols that have become the focus of much research because of their medicinal properties. For this paper, a new method to determine polyphenols in nutraceutical samples was developed, based on solid-liquid extraction and further analysis by liquid chromatography. Analytes were recovered by ultrasound-assisted extraction, using a mixture of methanol/water/hydrochloric acid (70:29:1, v:v:v) as the solvent. Reversed-phase high-performance liquid chromatography with ultraviolet/visible (HPLC-UV/Vis) and fluorescence detection (HPLC-FLD) were developed to determine the content of the principal flavanols. The HPLC-FLD method showed better selectivity and sensitivity, so it was selected for further studies. The analytical parameters established with FLD were satisfactory in terms of linearity (R2 ≥ 0.993), repeatability (RSD% ≥ 2.2), and limits of detection of 0.1 mg L−1 or below. The nutraceutical samples were analyzed by HPLC-FLD to determine the compositional profiles of flavanols, then they were subsequently treated using chemometric methods, such as principal component analysis (PCA). Results showed that the study of compositional profiles from the selected flavanols was sufficient for description and discrimination purposes. The cranberry samples were the richest in flavanols, procyanidin A2 being the principal flavanol, and artichoke samples the least rich.
      Citation: Separations
      PubDate: 2022-03-30
      DOI: 10.3390/separations9040087
      Issue No: Vol. 9, No. 4 (2022)
  • Separations, Vol. 9, Pages 88: Effect of Internal Vortex-Finder on
           Classification Performance for Double Vortex-Finder Hydrocyclone

    • Authors: Yuekan Zhang, Jiangbo Ge, Lanyue Jiang, Hui Wang, Yaoxu Duan
      First page: 88
      Abstract: The double vortex-finder hydrocyclone formed by a coaxial insertion of an internal vortex-finder with a smaller diameter inside the conventional single vortex-finder used to obtain two kinds of products from the internal and external overflows in one classification has attracted wide attention. To further improve the classification performance of the hydrocyclone, the effects of the internal vortex-finder diameter and length on the classification performance were studied by numerical simulation and response surface modeling with the behavior of fluid and particle motion in the double vortex-finder hydrocyclone as the research object. The results showed that the split ratio and pressure drop of internal and external overflow increased with the diameter of the internal vortex-finder. The classification performance was optimal when the diameter ratio of internal and external overflow was 0.88, the yield of −20 μm particles was more than 80.0%, and the highest was 95.0%. Increasing the internal vortex-finder length could reduce the coarse particle content and improve the classification accuracy of the internal overflow product. When the length of the internal vortex-finder is larger than 80 mm, the +30 μm yield was lower than 20.0%, and the maximum k value was 16.3%; the k is the significant factor used to characterize the effectiveness of −20 μm particle collection. The response surface modeling revealed that the internal vortex-finder diameter was the most important factor affecting the distribution rate of internal overflow. This paper is expected to advance the development of the classification industry.
      Citation: Separations
      PubDate: 2022-03-31
      DOI: 10.3390/separations9040088
      Issue No: Vol. 9, No. 4 (2022)
  • Separations, Vol. 9, Pages 89: Separation of Serum and Plasma Proteins for
           In-Depth Proteomic Analysis

    • Authors: Joseph Paul, Timothy D. Veenstra
      First page: 89
      Abstract: There are probably no biological samples that did more to spur interest in proteomics than serum and plasma. The belief was that comparing the proteomes of these samples obtained from healthy and disease-affected individuals would lead to biomarkers that could be used to diagnose conditions such as cancer. While the continuing development of mass spectrometers with greater sensitivity and resolution has been invaluable, the invention of strategic strategies to separate circulatory proteins has been just as critical. Novel and creative separation techniques were required because serum and plasma probably have the greatest dynamic range of protein concentration of any biological sample. The concentrations of circulating proteins can range over twelve orders of magnitude, making it a challenge to identify low-abundance proteins where the bulk of the useful biomarkers are believed to exist. The major goals of this article are to (i) provide an historical perspective on the rapid development of serum and plasma proteomics; (ii) describe various separation techniques that have made obtaining an in-depth view of the proteome of these biological samples possible; and (iii) describe applications where serum and plasma proteomics have been employed to discover potential biomarkers for pathological conditions.
      Citation: Separations
      PubDate: 2022-04-01
      DOI: 10.3390/separations9040089
      Issue No: Vol. 9, No. 4 (2022)
  • Separations, Vol. 9, Pages 90: Chemical Profiling and Characterization of
           Different Cultivars of Cannabis sativa L. Inflorescences by SPME-GC-MS and

    • Authors: Vittoria Cicaloni, Laura Salvini, Sara Vitalini, Stefania Garzoli
      First page: 90
      Abstract: The chemical profile of the Cannabis sativa L. female inflorescences is rather complex being characterized by a large number of molecules belonging to different chemical classes. Considering the numerous applications in various fields, including the medical and pharmaceutical sectors, that have seen a large use of Cannabis genus in recent years, a precise characterization of the matrices is essential. In this regard, the application of adequate and suitable sampling and analysis techniques becomes important in order to provide an identification of the metabolites characterizing the profile of the sample under examination. The goal of this work is to provide additional information on the chemical composition of the inflorescences of five C. sativa different cultivars grown in Emilia Romagna (Italy) through the application of sophisticated analysis techniques such as Solid-Phase Microextraction-Gas Chromatography-Mass Spectrometry and Ultra-Performance Liquid Chromatography-Mass Spectrometry (SPME-GC-MS and UPLC-MS). The obtained data highlighted the presence of a high number of volatile and non-volatile compounds, thus allowing a comparative evaluation of the different samples. Furthermore, an in-depth statistical survey by Principal Components Analysis (PCA) and HeatMap, Hierarchical luster Analysis (HCA) and Partial Least Squares Discriminant Analysis (PLS-DA-VIP), was conducted to consider any correlations between the investigated cultivars. The findings of this study may help to provide more information on the C. sativa inflorescences useful for potential applications of their metabolites in scientific research.
      Citation: Separations
      PubDate: 2022-04-02
      DOI: 10.3390/separations9040090
      Issue No: Vol. 9, No. 4 (2022)
  • Separations, Vol. 9, Pages 91: QuEChERS Method Combined with Gas- and
           Liquid-Chromatography High Resolution Mass Spectrometry to Screen and
           Confirm 237 Pesticides and Metabolites in Cottonseed Hull

    • Authors: Kaixuan Tong, Yujie Xie, Siqi Huang, Yongcheng Liu, Xingqiang Wu, Chunlin Fan, Hui Chen, Meiling Lu, Wenwen Wang
      First page: 91
      Abstract: Cottonseed hull is a livestock feed with large daily consumption. If pesticide residues exceed the standard, it is easy for them to be introduced into the human body through the food chain, with potential harm to consumer health. A method for multi-residue analysis of 237 pesticides and their metabolites in cottonseed hull was developed by gas-chromatography and liquid-chromatography time-of-flight mass spectrometry (GC-QTOF/MS and LC-QTOF/MS). After being hydrated, a sample was extracted with 1% acetic acid in acetonitrile, then purified in a clean-up tube containing 400 mg MgSO4, 100 mg PSA, and 100 mg C18. The results showed that this method has a significant effect in removing co-extracts from the oily matrix. The screening detection limit (SDL) was in the range of 0.2–20 μg/kg, and the limit of quantification (LOQ) was in the range of 0.2–20 μg/kg. The recovery was verified at the spiked levels of 1-, 2-, and 10-times LOQ (n = 6), and the 237 pesticides were successfully verified. The percentages of pesticides with recovery in the range of 70–120% were 91.6%, 92.8%, and 94.5%, respectively, and the relative standard deviations (RSDs) of all pesticides were less than 20%. This method was successfully applied to the detection of real samples. Finally, this study effectively reduced the matrix effect of cottonseed hull, which provided necessary data support for the analysis of pesticide residues in oil crops.
      Citation: Separations
      PubDate: 2022-04-02
      DOI: 10.3390/separations9040091
      Issue No: Vol. 9, No. 4 (2022)
  • Separations, Vol. 9, Pages 92: Modified Polyethersulfone Ultrafiltration
           Membrane for Enhanced Antifouling Capacity and Dye Catalytic Degradation

    • Authors: Mingming Wang, Feiyun Sun, Haojie Zeng, Xiaoli Su, Guofei Zhou, Hao Liu, Dingyu Xing
      First page: 92
      Abstract: Catalytic membranes, as a combination of heterogeneous advanced oxidation and membrane technology reaction systems, have important application prospects in the treatment of dyes and other organics. In practical applications, it is still challenging to construct catalytic membranes with excellent removal efficiency and fouling mitigation. Herein, molybdenum disulfide-iron oxyhydroxide (MoS2-FeOOH) was fabricated using iron oxide and MoS2 nanoflakes, which were synthesized by the hydrothermal method. Furthermore, by changing the concentration of MoS2-FeOOH, the MoS2-FeOOH/polyethersulfone (PES) composite ultrafiltration membrane was obtained with improved hydrophilicity, permeability, and antifouling capacity. The pure water flux of the composite membrane reached 385.3 L/(m2 h), which was 1.7 times that of the blank PES membrane. Compared with the blank membrane, with the increase of MoS2-FeOOH content, the MoS2-FeOOH/PES composite membranes had better adsorption capacity and catalytic performance, and the membrane with 3.0% MoS2-FeOOH content (M4) could be achieved at a 60.2% methylene blue (MB) degradation rate. In addition, the membrane flux recovery ratio (FRR) of the composite membrane also increased from 25.6% of blank PES membrane (M0) to more than 70% after two cycles of bovine serum albumin (BSA) filtration and hydraulic cleaning. The membrane with 2.25% MoS2-FeOOH content (M3) had the best antifouling performance, with the largest FRR and the smallest irreversible ratio (Rir). Catalytic self-cleaning of the composite membrane M3 recovered 95% of the initial flux with 0.1 mol/L H2O2 cleaning. The MoS2-FeOOH/PES composite membranes with the functions of excellent rejection and antifouling capacity have a good prospect in the treatment of printing and dyeing wastewater composed of soluble dyes.
      Citation: Separations
      PubDate: 2022-04-04
      DOI: 10.3390/separations9040092
      Issue No: Vol. 9, No. 4 (2022)
  • Separations, Vol. 9, Pages 93: Simultaneous Determination of Methyl
           Nicotinate and Three Salicylic Acid Derivatives in Pain Relief Spray Using

    • Authors: Hazim M. Ali
      First page: 93
      Abstract: For the first time, the high-performance liquid chromatography–diode array detector (HPLC–DAD) approach was operated for the simultaneous assessment of methyl nicotinate (MN), methyl salicylate (MS), ethyl salicylate (ES) and 2-hydroxyethyl salicylate (HES) in one pharmaceutical formulation. The limits of detection of MN, HES, MS and ES were found to be 0.0144, 0.0455, 0.0087 and 0.0061 μg/mL. The recovery percentages and relative standard deviations ranged from 93.48 to 102.12% and 0.301 to 6.341% for all active ingredients. Accordingly, the previously described data demonstrate the sensitivity, accuracy and precision of the developed method. Therefore, the investigated approach was effectively applied for the simultaneous assessment of MN, HES, MS and ES in DEEP HEAT Spray.
      Citation: Separations
      PubDate: 2022-04-06
      DOI: 10.3390/separations9040093
      Issue No: Vol. 9, No. 4 (2022)
  • Separations, Vol. 9, Pages 94: A High-Performance Thin-Layer
           Chromatographic Method for the Simultaneous Determination of Curcumin I,
           Curcumin II and Curcumin III in Curcuma longa and Herbal Formulation

    • Authors: Maged S. Abdel-Kader, Ayman A. Salkini, Prawez Alam, Khaled A. Alshahrani, Ahmed I. Foudah, Mohammed H. Alqarni
      First page: 94
      Abstract: Curcuma longa (turmeric) has traditionally been used in Ayurvedic, Unani and herbal drugs to cure numerous ailments. Due to the high demand, the quantitative standardization of herbal products is challenging to maintain their quality. We aim to develop a rapid, sensitive and validated high-performance thin-layer chromatography (HPTLC) method for the simultaneous determination and quantification of curcumin I, curcumin II and curcumin III in C. longa and herbal formulation. The three standards were separated using centrifugal preparative thin-layer chromatography (CPTLC) silica gel and identified by different spectroscopic methods. The developed HPTLC method was validated by following ICH guidelines (linearity; limit of detection, LOD; limit of quantitation; accuracy; precision; and robustness). The calibration curves of both the compounds were linear (50–500 ng/spot), with a correlation coefficient (r2) of >999. The developed HPTLC method was effectively applied to the concurrent detection and quantification of curcumins I–III in fresh, dry rhizomes and the herbal formulation of C. longa extracts was obtained by hot and cold extraction methods.
      Citation: Separations
      PubDate: 2022-04-10
      DOI: 10.3390/separations9040094
      Issue No: Vol. 9, No. 4 (2022)
  • Separations, Vol. 9, Pages 95: Simulation of CO2 Capture Process in Flue

    • Authors: Xiaoting Huang, Ning Ai, Lan Li, Quanda Jiang, Qining Wang, Jie Ren, Jiawei Wang
      First page: 95
      Abstract: Oxy-fuel combustion technology is an effective way to reduce CO2 emissions. An ionic liquid [emim][Tf2N] was used to capture the CO2 in flue gas from oxy-fuel combustion plant. The process of the CO2 capture was simulated using Aspen Plus. The results show that when the liquid–gas ratio is 1.55, the volume fraction of CO2 in the exhaust gas is controlled to about 2%. When the desorption pressure is 0.01 MPa, desorption efficiency is 98.2%. Additionally, based on the designability of ionic liquids, a hypothesis on the physical properties of ionic liquids is proposed to evaluate their influence on the absorption process and heat exchanger design. The process evaluation results show that an ionic liquid having a large density, a large thermal conductivity, and a high heat capacity at constant pressure is advantageous. This paper shows that from capture energy consumption and lean circulation, oxy-fuel combustion is a more economical method. Furthermore, it provides a feasible path for the treatment of CO2 in the waste gas of oxy-fuel combustion. Meanwhile, Aspen simulation helps speed up the application of ionic liquids and oxy-fuel combustion. Process evaluation helps in equipment design and selection.
      Citation: Separations
      PubDate: 2022-04-11
      DOI: 10.3390/separations9040095
      Issue No: Vol. 9, No. 4 (2022)
  • Separations, Vol. 9, Pages 96: Recent Advances on Ionic Liquid Uses in
           Separation Techniques

    • Authors: María José Ruiz-Ángel, Samuel Carda-Broch
      First page: 96
      Abstract: Ionic liquids (ILs) are non-molecular solvents; specifically, molten salts with low melting points, often below 100 °C and even below room temperature, thus allowing these solvents to remain liquid [...]
      Citation: Separations
      PubDate: 2022-04-11
      DOI: 10.3390/separations9040096
      Issue No: Vol. 9, No. 4 (2022)
  • Separations, Vol. 9, Pages 97: Generation of Controlled
           Liquid–Liquid Slug Flow by Interlocking Two Diaphragm Pumps

    • Authors: Akinori Muto, Hidetaka Abe, Keita Kanki, Takashi Fukuda, Shin-ichiro Kawasaki
      First page: 97
      Abstract: From the viewpoint of resource and energy-saving, the high extraction rate of alternating liquid–liquid flow (slug flow) is important given that it enables its novel use in extraction. Additionally, a specific extraction rate must be maintained for the practical application of slug flow to chemical extraction. Although slug flow is easily generated, controlling the slug length is difficult. In this study, two diaphragm pumps were interlocked to generate a slug flow. By linking the movement of the diaphragms of the two pumps, we could successfully and efficiently control the slug length, and the interlocking diaphragms could easily control the length of the aqueous and oil phase segments of the slug flow. The lengths of the aqueous and oil phases of the slug flow, which could not be quantitatively controlled, could be expressed in terms of the linear velocity of the liquid, the kinematic viscosity, and the tube diameter using the Reynolds number. This relation aids the extraction equipment design using slug flow. Furthermore, the mass transfer coefficient of extraction obtained using the slug flow generated by the developed device was similar to that obtained by the conventional method of a syringe pump. These results indicate that slug flow can be successfully applied to extraction processes.
      Citation: Separations
      PubDate: 2022-04-12
      DOI: 10.3390/separations9040097
      Issue No: Vol. 9, No. 4 (2022)
  • Separations, Vol. 9, Pages 98: Development of a High-Throughput Screening
           Analysis for 195 Pesticides in Raw Milk by Modified QuEChERS Sample
           Preparation and Liquid Chromatography Quadrupole Time-of-Flight Mass

    • Authors: Xingqiang Wu, Kaixuan Tong, Changyou Yu, Shuang Hou, Yujie Xie, Chunlin Fan, Hui Chen, Meiling Lu, Wenwen Wang
      First page: 98
      Abstract: This study aimed to develop a simple, high-throughput method based on modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) followed by liquid chromatography quadrupole time-of-flight mass spectrometry (LC-Q-TOF/MS) for the rapid determination of multi-class pesticide residues in raw milk. With acidified acetonitrile as the extraction solvent, the raw milk samples were pretreated with the modified QuEChERS method, including extraction, salting-out, freezing, and clean-up processes. The target pesticides were acquired in a positive ion electrospray ionization mode and an All ions MS/MS mode. The developed method was validated, and good performing characteristics were achieved. The screening detection limits (SDL) and limits of quantitation (LOQ) for all the pesticides ranged within 0.1–20 and 0.1–50 μg/kg, respectively. The recoveries of all analytes ranged from 70.0% to 120.0% at three spiked levels (1 × LOQ, 2 × LOQ, and 10 × LOQ), with relative standard deviations less than 20.0%. The coefficient of determination was greater than 0.99 within the calibration linearity range for the detected 195 pesticides. The method proved the simple, rapid, high throughput screening and quantitative analysis of pesticide residues in raw milk.
      Citation: Separations
      PubDate: 2022-04-12
      DOI: 10.3390/separations9040098
      Issue No: Vol. 9, No. 4 (2022)
  • Separations, Vol. 9, Pages 99: Analytical Determination of Allergenic
           Fragrances in Indoor Air

    • Authors: Catia Balducci, Marina Cerasa, Pasquale Avino, Paolo Ceci, Alessandro Bacaloni, Martina Garofalo
      First page: 99
      Abstract: Among all the emerging contaminants, fragrances are gaining more relevance for their proven allergenic and, in some cases, endocrine-disrupting properties. To date, little information exists on their concentration in the air. This study aims to fill this gap by developing a method for the determination of semivolatile fragrances in the indoor gaseous phase with sampling protocols usually adopted for the collection of atmospheric particulate matter (sampling time 24 h, flow rate 10 L min−1) and instrumental analysis by gas chromatography coupled with mass spectrometry. The method was developed on 66 analytes and tested at three concentration levels: 20 compounds showed analytical recoveries ≥72% with percentage standard deviations always better than 20%. For most compounds, negligible sampling breakthroughs were observed. The method was then applied to real samples collected in a coffee bar and in a private house. Considering the fragrances for which the method has shown good effectiveness, the highest concentrations were observed for carvone in the coffee bar (349 ng m−3) and camphor in the house (157 ng m−3). As concerns certain or suspected endocrine disruptors, lilyal and galaxolide were detected at both sites, α-isomethylionone was the second most concentrated compound in the house (63.2 ng m−3), musk xylene and musk ketone were present at lower concentration (≈ 1 or 2 ng m−3).
      Citation: Separations
      PubDate: 2022-04-13
      DOI: 10.3390/separations9040099
      Issue No: Vol. 9, No. 4 (2022)
  • Separations, Vol. 9, Pages 100: Wet Process Phosphoric Acid Purification
           Using Functionalized Organic Nanofiltration Membrane

    • Authors: Khaoula Khaless, Hamza Chanouri, Said Amal, Abla Ouaattou, El Mahdi Mounir, Hicham Haddar, Rachid Benhida
      First page: 100
      Abstract: The utilization of phosphoric acid in various sectors, e.g., food industry, is controlled by the authorized concentration limit of impurities. However, industrial phosphoric acid is contaminated with undesirable impurities (such as F, Al, Fe, Mg, etc.). Herein, this study aimed to evaluate the efficiency of the membrane purification process of pretreated industrial phosphoric acid using a premodified nanofiltration membrane. We demonstrated that the prior pretreatment steps for industrial phosphoric acid allowed the elimination of sulfate, fluorine and arsenic. Further purification of the obtained pretreated phosphoric acid using membrane cells reduced the concentrations of Cd, Al, Fe and rare earth elements by 94.81, 99.30, 99.63 and 96.67%, respectively. The membrane is functionalized by a deposit of a high molecular weight polycationic polymer of polyethyleneimines in order to produce a highly charged membrane surface to enhance the separation efficiency, selectivity and stability of the membrane. We found that the purification process relies on electrostatic repulsion between the functionalized membrane and highly charged ions, and the reduction rate of metals is a cation charge-dependent parameter. The laboratory and industrial pilot scale results showed that this process allows the production of food-grade phosphoric acid.
      Citation: Separations
      PubDate: 2022-04-14
      DOI: 10.3390/separations9040100
      Issue No: Vol. 9, No. 4 (2022)
  • Separations, Vol. 9, Pages 101: Separation and Determination of Biophenols
           in Olive Oil Samples Based on the Official Method of the International
           Olive Council and Commission Regulation (EU) No. 432/2012

    • Authors: Konstantina Papastavropoulou, Ioannis N. Pasias, Elissavet Dotsika, Emel Oz, Fatih Oz, Charalampos Proestos
      First page: 101
      Abstract: The purpose of this study was to evaluate the key quality characteristics of olive oil with a main focus on the biophenolic content, its beneficial effects on health and the contribution of various quality characteristics to its health claims, as well as its influence from various parameters. Samples from different traditional oil-producing regions of Greece were initially examined for the most important quality parameters, such as the percentage of free acidity, the number of peroxides and the spectrophotometric investigation in the ultraviolet. The samples were then tested for their biophenolic content, expressed in milligrams of tyrosol, and its derivatives per 20 g of olive oil using the analytical technique high-performance liquid chromatography (HPLC). Then, the biophenol contents of the analyzed samples were compared based on the presented intensities in terms of the variety and the area of cultivation, the altitude, the type of cultivation, the extraction system in the mill and the time interval from olive harvest to oiling. Finally, according to the results, the content of biophenols in olive oil and its health claims were found to be influenced by the various parameters with which they were compared.
      Citation: Separations
      PubDate: 2022-04-15
      DOI: 10.3390/separations9040101
      Issue No: Vol. 9, No. 4 (2022)
  • Separations, Vol. 9, Pages 102: Application of a Validated Method for the

    • Authors: Artemis P. Louppis, Michalis S. Constantinou
      First page: 102
      Abstract: The aim of the present study was to develop a rapid, simple and reliable method for the identification and quantification of six mycotoxins in wine using liquid chromatography with electrospray ionization tandem mass spectrometry. The analytical method was fully validated, and calibration curves were made with correlation coefficients >0.9970. A short analysis time and acceptable extraction efficiency were achieved by a direct extraction method of analytes (ochratoxin A, aflatoxin B1, B2, G1, G2 and Zearalenone) with acetonitrile. LOD values were from 0.03 to 0.27 μg kg−1, and LOQ values were from 0.08 to 0.81 μg kg−1, with recoveries at various values from 77 to 108%. The expanded uncertainty was 5–21% expressed at a coverage level of k = 2, at a confidence level of approximately 95%. The performance criteria of the method were fully met according to European legislation (EC) 401/2006. The method was successfully applied to wine samples from Cyprus. The method was simple, low cost, quick, accurate, and sensitive.
      Citation: Separations
      PubDate: 2022-04-15
      DOI: 10.3390/separations9040102
      Issue No: Vol. 9, No. 4 (2022)
  • Separations, Vol. 9, Pages 65: Market Survey of Modern Oral Nicotine
           Products: Determination of Select HPHCs and Comparison to Traditional
           Smokeless Tobacco Products

    • Authors: Joseph J. Jablonski, Andrew G. Cheetham, Alexandra M. Martin
      First page: 65
      Abstract: In an effort to combat the risks associated with traditional tobacco products, tobacco product innovation has been redirected towards reducing the consumer’s potential exposure to harmful or potentially harmful constituents (HPHCs). Among these innovations are modern oral nicotine products (MONPs). This product class aims to deliver nicotine while limiting the consumer’s potential toxicant exposure. This body of work sought to investigate the potential for select HPHC exposure (tobacco-specific nitrosamines, carbonyls, benzo[a]pyrene, nitrite, and metals) from MONPs and to compare it to that from traditional tobacco products. This work expands on previously published studies both in terms of diversity of products assessed and analytes tested. In total, twenty-one unique MONPs were assessed and compared to four traditional tobacco products. We found that there was a difference in the potential exposure based on the MONP filler—plant material vs. granulate/powder. Typically, the HPHC levels observed in plant-based MONPs were higher than those observed for granulate/powder products, most notably within the metals analysis, for which the levels were occasionally greater than those seen in traditional smokeless tobacco products. Generally, the overall HPHC levels observed in MONP were at or below those levels observed in traditional tobacco products.
      Citation: Separations
      PubDate: 2022-03-02
      DOI: 10.3390/separations9030065
      Issue No: Vol. 9, No. 3 (2022)
  • Separations, Vol. 9, Pages 66: Phytochemical and Nutritional Profile
           Composition in Fruits of Different Sweet Chestnut (Castanea sativa Mill.)
           Cultivars Grown in Romania

    • Authors: Corina Teodora Ciucure, Elisabeta-Irina Geana, Claudia Sandru, Ovidiu Tita, Mihai Botu
      First page: 66
      Abstract: Chestnut (Castanea sativa Mill.), a valuable fruit crop, is cultivated in small areas in Romania, mostly in the west, where the moderate continental climate has a slight Mediterranean influence. This work aims to investigate the bioactive characteristics (total polyphenols, total flavonoids and antioxidant activity), individual polyphenolic composition, phytochemical and nutritional HRMS screening profiles, sugar and mineral composition of six sweet chestnut cultivars, namely ‘Marsol’, ‘Maraval’, ‘Bournette’, ‘Précoce Migoule’ and ‘Marissard’ grown at Fruit Growing Research—Extension Station (SCDP) Vâlcea, in Northern Oltenia, Romania. Fruit samples were collected in two consecutive years, in order to study the impact of genetic variability between cultivars and the influence of the different climatic conditions corresponding to different cultivation years. Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) allow the discrimination between the sweet chestnut fruits harvested in different years and different sweet chestnut cultivars. Analytical investigations revealed that sweet chestnut cultivars grown in Romania show similar bioactive, phytochemical and nutritional composition to cultivars grown in the large European chestnut-producing countries, indicating the high adaptation potential of the chestnut in the temperate continental zone with small Mediterranean influences characteristic of the southwestern area of Romania.
      Citation: Separations
      PubDate: 2022-03-02
      DOI: 10.3390/separations9030066
      Issue No: Vol. 9, No. 3 (2022)
  • Separations, Vol. 9, Pages 67: Fractionation of Metal(loid)s in Three
           European Mine Wastes by Sequential Extraction

    • Authors: Chiamaka Belsonia Opara, Sabine Kutschke, Katrin Pollmann
      First page: 67
      Abstract: Mine waste can constitute an environmental hazard, especially when poorly managed. Environmental assessment is essential for estimating potential threats and optimizing mine waste management. This study evaluated the potential environmental risk of sulfidic mine waste samples originating from the Neves Corvo Mine, Portugal, and the closed Freiberg mining district, Germany. Metal(loid)s in the waste samples were partitioned into seven operationally defined fractions using the Zeien and Brummer sequential extraction scheme. The results showed similar partitioning patterns for the elements in the waste rock and tailing samples from Neves Corvo Mine; most metal(loid)s showed lower mobility, as they were mainly residual-bound. On the contrary, the Freiberg tailing sample had considerably elevated (24–37%) mobile fractions of Zn, Co, Cd, and Mn. The majority of Fe (83–96%) in all samples was retained in the residual fractions, while Ca was highly mobile. Overall, Pb was the most mobile toxic element in the three samples. A large portion of Pb (32–57%) was predominantly found in the most mobilizable fractions of the studied waste samples. This study revealed that the three mine wastes have contamination potential for Pb and Zn, which can be easily released into the environment from these waste sources.
      Citation: Separations
      PubDate: 2022-03-02
      DOI: 10.3390/separations9030067
      Issue No: Vol. 9, No. 3 (2022)
  • Separations, Vol. 9, Pages 68: Application of Untargeted Metabolomics to
           Determine Volatile Compounds from the Spanish Plant Arctostaphylos
           uva-ursi Used as Tea

    • Authors: Magdalena Wrona, Davinson Pezo, Maria Anna Rovito, Paula Vera, Cristina Nerín, Esther Asensio
      First page: 68
      Abstract: One-hundred and seven different volatile compounds were identified in the samples of Arctostaphylos uva-ursi collected from nine locations in Spain. This plant is commonly brewed and used as tea. Volatile compounds profile was detected using solid-phase microextraction gas chromatography-mass spectrometry. The most interesting compounds detected from an antioxidant capacity point of view were esters, phenols, and aromatics compounds. All samples were discriminated by principal component analysis. The insolation and altitude of harvest areas, and latent structures were considered for interpretation of results. Discriminant analysis was applied to control the type and concentration of metabolites and determine the best plant antioxidant profiles of volatile compounds from plant origin. Moreover, a heatmap displayed correlations between detected compounds. The discriminant analysis led to 20 quality markers being identified for the analysed plants. The strongest antioxidant capacity was obtained in the samples from Pina de Montalgrao and Loarre (collected in September) for ORAC (33.11 ± 0.61 g Trolox/g sample) and DPPH (IC50 = 711 ± 12 µg/g) methods, respectively. The plant with the highest total phenolic content was Loarre collected in September (171.9 ± 19.4 mg GAE/g DW) and November (177.1 ± 11.0 mg GAE/g DW).
      Citation: Separations
      PubDate: 2022-03-04
      DOI: 10.3390/separations9030068
      Issue No: Vol. 9, No. 3 (2022)
  • Separations, Vol. 9, Pages 69: Fabric Phase Sorptive Extraction for the
           Determination of Anthracyclines in Sewage

    • Authors: Sergio Santana-Viera, Alejandro Canino-Byreing, María Esther Torres-Padrón, Zoraida Sosa-Ferrera, José Juan Santana-Rodríguez, Abuzar Kabir, Kenneth G. Furton
      First page: 69
      Abstract: Anthracyclines are a group of antineoplastic compounds used to treat acute leukemia and other cancers, and they are excreted after consumption by patients. These chemicals are often found in sewage at very low concentration levels. For this reason, the development of sensitive analytical methodologies capable of determining them at low concentrations is of prime importance. A simple, fast and sensitive analytical method using fabric phase sorptive extraction (FPSE) followed by ultra-high performance liquid chromatography with fluorescence detection (UHPLC-FD) has been developed and validated for the extraction of anthracyclines from sewage samples. FPSE is a green, cheap, simple, selective and rapid sample preparation technique. The different parameters that affect the performance of the FPSE process, including extraction time, eluting solvent, elution time and pH, were optimized. The developed method showed satisfactory reproducibility, with intraday and interday RSD values lower than 15% for all the compounds and limits of detection between 0.1–0.15 µg·L−1. The unique combination of sample preparation by this micro-extraction technique with fluorescence detector have resulted in the satisfactory extraction of highly polar anthracyclines, without any noticeable matrix effect, a very common shortcoming of exhaustive sample preparation technique such as solid phase extraction (SPE) and mass spectrometry.
      Citation: Separations
      PubDate: 2022-03-04
      DOI: 10.3390/separations9030069
      Issue No: Vol. 9, No. 3 (2022)
  • Separations, Vol. 9, Pages 70: Determination of Alternaria Toxins in Food
           by SPE and LC-IDMS: Development and In-House Validation of a Candidate
           Method for Standardisation

    • Authors: Carlos Gonçalves, Ádam Tölgyesi, Katrien Bouten, Fernando Cordeiro, Joerg Stroka
      First page: 70
      Abstract: Alternaria toxins (ATs) are frequently found contaminants in foodstuffs (e.g., alternariol), often reaching high concentrations (e.g., tenuazonic acid). They can spoil a wide variety of food categories (e.g., cereals, vegetables, seeds and drinks) and storage at fridge temperatures does not prevent the growth of Alternaria fungi. Therefore, reliable and validated analytical methods are needed to protect human health and to ensure a transparent and fair trade. This paper describes new technical features that improved a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the analysis of ATs in tomato, wheat and sunflower seeds. This analytical method should be simple to implement in different laboratories across the EU and thus be an attractive candidate for standardisation. The major element for improvement was the use of isotopically labelled internal standards, only recently commercially available, thereby reducing the sample handling and improving the accuracy of the results. In addition, the sample extraction and the solid-phase extraction (SPE) enrichment/clean-up were fine-tuned, whereas a more suitable analytical column (XSelect HSS T3) with improved selectivity was also employed. Overall, this method shows adequate precision (repeatability < 5.7% RSD; intermediate precision < 7.0% RSD) and trueness (recoveries ranging from 74% to 112%). The limits of quantification in wheat (the most analytically demanding matrix) vary between 0.19 and 1.40 µg/kg. These figures were deemed satisfactory by the European Committee for Standardization (CEN) and have formed the basis for a subsequent interlaboratory validation study. The corresponding standard was published by CEN in 2021.
      Citation: Separations
      PubDate: 2022-03-08
      DOI: 10.3390/separations9030070
      Issue No: Vol. 9, No. 3 (2022)
  • Separations, Vol. 9, Pages 71: Semi-Quantitative and Qualitative
           Distinction of Aromatic and Flavour Compounds in Charcoal Grilled,
           Electric Barbecue Grilled, Infrared Grilled and Superheated-Steam Roasted
           Lamb Meat Patties Using GC/MC, E-nose and E-tongue

    • Authors: Raheel Suleman, Teng Hui, Zhenyu Wang, Alma Delia Alarcon-Rojo, Huan Liu, Dequan Zhang
      First page: 71
      Abstract: This study investigated the influence of four different methods of cooking (charcoal grilling, electric barbecue grilling, superheated-steam roasting and infrared grilling) on the volatile profile of lamb meat patties. The study included the patties of the oyster cut muscle of lambs cooked using charcoal grilling, electric barbecue grilling, infrared grilling and superheated-steam roasting methods. The principal component analysis (PCA) of electric nose data showed a total variance of 73.71%. The e-nose values showed differentiation of the volatiles released from the lamb meat patties. Data of PCA of e-nose and GC-MS revealed good separation between groups. Significance (p < 0.05) was found for the flavour profile values of charcoal-grilled and superheated-steam-roasted samples while the lowest significance was observed between infrared- and electric-barbecue-grilled samples. Saltiness and sourness were higher in superheated-steam-roasted patties than charcoal-grilled samples through e-tongue. The main volatile compound found in all the lamb patties was 2,3-octanedione with a content of 20.43 µg/g–27.83 µg/g. 1-hexanol was highest at 34.74 µg/g in the charcoal-grilled samples while 2,3-octanedione was highest at 35.83 µg/g in superheated-steam-roasted patties.
      Citation: Separations
      PubDate: 2022-03-08
      DOI: 10.3390/separations9030071
      Issue No: Vol. 9, No. 3 (2022)
  • Separations, Vol. 9, Pages 72: The Crosslinker Matters:
           Vinylimidazole-Based Anion Exchange Polymer for Dispersive Solid-Phase
           Extraction of Phenolic Acids

    • Authors: Matthias Harder, Rania Bakry, Felix Lackner, Paul Mayer, Christoph Kappacher, Christoph Grießer, Sandro Neuner, Christian W. Huck, Günther K. Bonn, Matthias Rainer
      First page: 72
      Abstract: Crosslinkers are indispensable constituents for the preparation of SPE materials with ethylene glycol dimethacrylate (EGDMA) and divinylbenzene (DVB) among the most prominent representatives. A crosslinker that has not yet been used for the preparation of SPE sorbents is 3,3’-(hexane-1,6-diyl)bis(1-vinylimidazolium) bromide [C6-bis-VIM] [Br]. In this study, we synthesized differently crosslinked vinylimidazole polymers with EGDMA, DVB and [C6-bis-VIM] [Br] and evaluated their extraction efficiencies towards phenolic acids. Dispersive SPE experiments performed with the [C6-bis-VIM] [Br] crosslinked polymers exhibited significantly higher extraction recoveries for the majority of analytes. Due to these promising results, the [C6-bis-VIM] [Br] crosslinked polymer was optimized in terms of the monomer to crosslinker ratio and an efficient dispersive SPE protocol was developed, with maximum recoveries ranging from 84.1–92.5% and RSD values ˂ 1%. The developed extraction procedure was also applied to cartridges resulting in recoveries between 97.2 and 98.5%, which were on average 5% higher than with the commercial anion exchange sorbent Oasis® MAX. Furthermore, the sorbent was regenerated showing a good reusability for the majority of analytes. In conclusion, this study clearly highlights the yet untapped potential of the crosslinker, [C6-bis-VIM] [Br], with respect to the synthesis of efficient anion exchange polymers for SPE.
      Citation: Separations
      PubDate: 2022-03-08
      DOI: 10.3390/separations9030072
      Issue No: Vol. 9, No. 3 (2022)
  • Separations, Vol. 9, Pages 73: The Bright and Dark Sides of Reactive
           Oxygen Species Generated by Copper–Peptide Complexes

    • Authors: Urszula K. Komarnicka, Monika K. Lesiów, Maciej Witwicki, Alina Bieńko
      First page: 73
      Abstract: Copper ions bind to biomolecules (e.g., peptides and proteins) playing an essential role in many biological and physiological pathways in the human body. The resulting complexes may contribute to the initiation of neurodegenerative diseases, cancer, and bacterial and viral diseases, or act as therapeutics. Some compounds can chemically damage biological macromolecules and initiate the development of pathogenic states. Conversely, a number of these compounds may have antibacterial, antiviral, and even anticancer properties. One of the most significant current discussions in Cu biochemistry relates to the mechanisms of the positive and negative actions of Cu ions based on the generation of reactive oxygen species, including radicals that can interact with DNA molecules. This review aims to analyze various peptide–copper complexes and the mechanism of their action.
      Citation: Separations
      PubDate: 2022-03-11
      DOI: 10.3390/separations9030073
      Issue No: Vol. 9, No. 3 (2022)
  • Separations, Vol. 9, Pages 74: Study on the Desliming Performance of a
           Novel Hydrocyclone Sand Washer

    • Authors: Xinghua Yang, Guanghui Yang, Peikun Liu, Xiaoyu Li, Lanyue Jiang, Jiashun Zhang
      First page: 74
      Abstract: A novel hydrocyclone sand washer featured by connecting a cylindrical hydrocyclone and a conical-cylindric hydrocyclone in series was developed to improve the poor grading performance in current machine-made sand processing technology. The former hydroycyclone with a flat bottom was designed to enhance the centrifugal intensity, thereby achieving the pre-grading of fine and coarse particles and ensuring the discharge of most fine mud particles from the overflow pipe. The latter hydrocyclone was designed to achieve the secondary fine separation and therefore reduce the content of fine particles in the underflow product. Firstly, the flow field inside the consecutive hydrocyclones was simulated using an RSM and VOF model. The DPM model was introduced to trace the particle motion trajectory and validate the feasibility of hydrocyclone separation. Then, the experimental study was performed using the control variable method, and the effects of the first-section overflow pipe diameter, the feeding rate, and the mud–sand mixing ratio on the desliming performance were examined. Results show that the content of particles with a diameter of below 75μm in the second-section underflow drops significantly after the separation in the hydrocyclone sand washer. When the first-section overflow pipe diameter, the feeding rate, and the mud–sand mixing ratio are set to 34 mm, 60 kg/h and 1:1, respectively, the desliming rate of the novel hydrocyclone sand washer can reach 94.31% and the loss rate of quartz sand is only 1.28%.
      Citation: Separations
      PubDate: 2022-03-13
      DOI: 10.3390/separations9030074
      Issue No: Vol. 9, No. 3 (2022)
  • Separations, Vol. 9, Pages 75: UPLC MS/MS Profile and Antioxidant
           Activities from Nonpolar Fraction of Patiwala (Lantana camara) Leaves

    • Authors: Ruslin, Yamin, Nur Arifka Rahma, Irnawati, Abdul Rohman
      First page: 75
      Abstract: One of the plants used in Indonesian traditional medicine, namely, Patiwala (Lantana camara), is traditionally used to treat some diseases, including itching, wounds, ulcers, swelling, eczema, tetanus, malaria, tumors, rheumatism, and headaches. This study aimed to characterize the compound nonpolar fraction of Patiwala leaf capable of scavenging free radicals. The characterization of compound was carried out using the Ultra-Performance Liquid Chromatography–tandem Mass Spectrometry (UPLC-MS/MS) with positive ion method, while the antioxidant testing was carried out using the radical DPPH (2,2-diphenyl-1-picrylhidrazyl) and FRAP (ferric reducing antioxidant power) methods. The results showed that the nonpolar fraction of the methanol extract of L. camara leaves was very strong toward DPPH radicals (IC50 34.65 ± 1.26 μg/mL and 40.23 ± 0.18 μg/mL), and FRAP radical (IC50 4.93 ± 0.22 μg/mL and 12.79 ± 0.09 μg/mL). Nineteen compounds identified by UPLC-MS/MS method were Resveratrol dimer, iso-humolones, oleuropein glucoside, quercetin-3-O-glycoside, myricetin, oleuropein, 12-deoxy-16-hydroxy-phorbol, aloeresin A, humulones, ursolic acid, viniferin, Epicatechin, oleanolic acid, 5-hydroxy-3′,4′,7-trimerthoxy-flavanone, Apigenin-6,8-di-C-β-D-glucoside, procyanidin A2, caffeoyl-O-hexoside, tansihnone IIA, and phillyrin. The methanolic extract of L. camara leaves can be developed as a source of antioxidants from natural ingredients.
      Citation: Separations
      PubDate: 2022-03-15
      DOI: 10.3390/separations9030075
      Issue No: Vol. 9, No. 3 (2022)
  • Separations, Vol. 9, Pages 76: Systematic Identification of Bioactive
           Compositions in Leaves of Morus Cultivars Using UHPLC-ESI-QTOF-MS/MS and
           Comprehensive Screening of High-Quality Resources

    • Authors: Xiang-Yue Zou, Ying-Jie He, Yi-Hui Yang, Xin-Pei Yan, Zhang-Bao Li, Hua Yang
      First page: 76
      Abstract: Morus spp. leaves (MSLs) show various beneficial effects in the treatment of metabolic-related diseases, which have created a growing interest in MSL development as dietary supplements and functional foods. The illustration of chemical compositions and screening of high-quality MSL resources are therefore necessary for further application. This study developed a new UHPLC-ESI-QTOF-MS/MS strategy of in-source collision-induced dissociation (IS-CID) and target collision-cell CID (TCC-CID) to quickly capture analogues with consistent skeleton, and combined global natural product social molecular networking (GNPS) to efficiently annotate bioactive phytochemicals in MSLs. For the results, 49 bioactive ingredients, including quercetin-type flavonoids, kaempferol-type flavonoids, chlorogenic acid isomers, 1-deoxynojirimycin, γ-aminobutyric acid, amino acids, and unsaturated fatty acids, were systematically identified in MSLs for the first time. Quantification for the typical components was simultaneously carried out in MSLs of 90 Morus resources collected from different locations. Partial least squares discriminant analysis (PLS-DA) indicated that quercetin-3-O-(6″-O-malonyl)-glucoside, rutin, kaempferol-3-O-(6″-O-malonyl)-glucoside, kaempferol-3-O-rutinoside, and chlorogenic acid showed high variable importance in the project (VIP > 1) that were significant constituents for the differences between MSL species. Then, high-quality MSLs were comprehensively screened in multiple Morus cultivars based on the criteria importance through intercriteria correlation (CRITIC) method. This study presented an efficient strategy to annotate bioactive compounds, revealed the difference of bioactive components in MSLs, and provided important information for the high-value production of Morus cultivars in food and supplement fields.
      Citation: Separations
      PubDate: 2022-03-15
      DOI: 10.3390/separations9030076
      Issue No: Vol. 9, No. 3 (2022)
  • Separations, Vol. 9, Pages 77: µQuEChERS Combined with UHPLC-PDA as
           a State-of-the-Art Analytical Approach for Quantification of Chlorpropham
           in Potato

    • Authors: Telma M. Gomes, Rosa Perestrelo, José S. Câmara
      First page: 77
      Abstract: Pesticides are chemicals used in agriculture to prevent insects, fungi, weeds, and other pests, from damaging crops. In addition, some types of pesticides are used after harvest as sprout suppressant agents help keeping the quality parameters of crops during storage. Nonetheless, its presence, even at trace levels, in food products is becoming a big challenge regarding human health. The current work aimed to develop and validate a sensitive and high-throughput analytical approach, based on a state-of-the-art microextraction technique—µQuEChERS, combined with ultra-high performance liquid chromatography equipped with a photodiode array detection system (UHPLC-PDA) to quantify isopropyl-N-(3-chlorophenyl) carbamate (chlorpropham), commonly used as efficient sprout suppressant stored potatoes, in raw and cooked potatoes cultivated in different geographical regions of Madeira Island (Portugal). Good results were obtained in terms of figures of the merit of the method, with correlation coefficients (R2) higher than 0.999 and recoveries between 94.5% to 125%. Method limit of detection (LOD) and limit of quantification (LOQ) were 0.14 μg/Kg and 0.43 μg/Kg, respectively, which are much lower than the accepted and legislated requirements by the European Union, which is 20 μg/Kg for chlorpropham. The concentration of chlorpropham in raw potatoes is significantly higher when compared to cooked samples, which revealed that the thermic treatment during cooking had a significant effect on its degradation. A significant decrease (90%, on average) was observed on chlorpropham levels.
      Citation: Separations
      PubDate: 2022-03-17
      DOI: 10.3390/separations9030077
      Issue No: Vol. 9, No. 3 (2022)
  • Separations, Vol. 9, Pages 78: Method Development and Applications for
           Reduced-Risk Products

    • Authors: Fadi Aldeek, Mohamadi A. Sarkar
      First page: 78
      Abstract: Cigarette smoking remains the leading cause of preventable premature death and disease in the U [...]
      Citation: Separations
      PubDate: 2022-03-18
      DOI: 10.3390/separations9030078
      Issue No: Vol. 9, No. 3 (2022)
  • Separations, Vol. 9, Pages 79: Adverse Effects of Arsenic Uptake in Rice
           Metabolome and Lipidome Revealed by Untargeted Liquid Chromatography
           Coupled to Mass Spectrometry (LC-MS) and Regions of Interest Multivariate
           Curve Resolution

    • Authors: Miriam Pérez-Cova, Romà Tauler, Joaquim Jaumot
      First page: 79
      Abstract: Rice crops are especially vulnerable to arsenic exposure compared to other cereal crops because flooding growing conditions facilitates its uptake. Besides, there are still many unknown questions about arsenic’s mode of action in rice. Here, we apply two untargeted approaches using liquid chromatography coupled to mass spectrometry (LC-MS) to unravel the effects on rice lipidome and metabolome in the early stages of growth. The exposure is evaluated through two different treatments, watering with arsenic-contaminated water and soil containing arsenic. The combination of regions of interest (ROI) and multivariate curve resolution (MCR) strategies in the ROIMCR data analyses workflow is proposed and complemented with other multivariate analyses such as partial least square discriminant analysis (PLS-DA) for the identification of potential markers of arsenic exposure and toxicity effects. The results of this study showed that rice metabolome (and lipidome) in root tissues seemed to be more affected by the watering and soil treatment. In contrast, aerial tissues alterations were accentuated by the arsenic dose, rather than with the watering and soil treatment itself. Up to a hundred lipids and 40 metabolites were significantly altered due to arsenic exposure. Major metabolic alterations were found in glycerophospholipids, glycerolipids, and amino acid-related pathways.
      Citation: Separations
      PubDate: 2022-03-18
      DOI: 10.3390/separations9030079
      Issue No: Vol. 9, No. 3 (2022)
  • Separations, Vol. 9, Pages 80: Fractional Separation and Characterization
           of Cuticular Waxes Extracted from Vegetable Matter Using Supercritical CO2

    • Authors: Mariarosa Scognamiglio, Lucia Baldino, Ernesto Reverchon
      First page: 80
      Abstract: Cuticular waxes can be used in high-value applications, including cosmetics, foods and nutraceuticals, among the others. The extraction process determines their quality and purity that are of particular interest when biocompatibility, biodegradability, flavor and fragrance are the main features required for the final formulations. This study demonstrated that supercritical fluid extraction coupled with fractional separation can represent a suitable alternative to isolate cuticular waxes from vegetable matter that preserve their natural properties and composition, without contamination of organic solvent residues. Operating in this way, cuticular waxes can be considered as a fingerprint of the vegetable matter, where C27, C29 and C31 are the most abundant compounds that characterize the material; the differences are mainly due to their relative proportions and the presence of hydrocarbon compounds possessing other functional groups, such as alcohols, aldehydes or acids. Therefore, selectivity of supercritical fluid extraction towards non-polar or slightly polar compounds opens the way for a possible industrial approach to produce extracts that do not require further purification steps.
      Citation: Separations
      PubDate: 2022-03-20
      DOI: 10.3390/separations9030080
      Issue No: Vol. 9, No. 3 (2022)
  • Separations, Vol. 9, Pages 81: The Evaluation of Amino Acid Profiles in
           Gluten-Free Mini Sponge Cakes Fortified with Broccoli By-Product

    • Authors: Natalia Drabińska
      First page: 81
      Abstract: Many gluten-free products are deficient in amino acids, especially in essential amino acids (EAA). Therefore, the incorporation of additives rich in free amino acids (FAA) into gluten-free products can be a promising strategy to alleviate certain symptoms of celiac disease associated with EAA deficiencies. This study aimed to evaluate the effect of the incorporation of broccoli leaf powder (BLP) into gluten-free mini sponge cakes (GFS) on the profile of FFA. BLP replaced an equivalent amount (2.5%, 5%, 7.5%; w/w) of corn and potato starches in GFS formulation, resulting in B1-B3 formulations. The first step was the selection of the most efficient method for extraction of FAA. Extraction based on 50% methanol (method 1) was compared to extraction by 25% of acetonitrile in 0.1 M hydrochloric acid (method 2). In total, 26 and 14 FAA were found in BLP after extraction using methods 1 and 2, respectively. Moreover, considering the total content of FAA, method 1 was more efficient, reaching a 14-fold higher concentration of FFA in BLP compared to method 2. The incorporation of BLP resulted in a significant increase in FAA, irrespective of the applied extraction method. The total concentrations of NEAA and EAA increased significantly in B3 compared to control GFS. In summary, this study showed that 50% methanol was more efficient for the extraction of FFA from plant and bakery matrices. Moreover, BLP was found as a good source of FFA, including EAA, and the obtained experimental GFS could be considered a promising product for individuals on a gluten-free diet.
      Citation: Separations
      PubDate: 2022-03-20
      DOI: 10.3390/separations9030081
      Issue No: Vol. 9, No. 3 (2022)
  • Separations, Vol. 9, Pages 82: Optimization and Validation of a Method
           Based on QuEChERS Extraction and Gas Chromatographic-Mass Spectrometric
           Analysis for the Determination of Polycyclic Aromatic Hydrocarbons and
           Polychlorinated Biphenyls in Olive Fruits Irrigated with Treated

    • Authors: Maria Concetta Bruzzoniti, Luca Rivoira, Michele Castiglioni, Enrico Cagno, Ahmed Kettab, Donatella Fibbi, Massimo Del Bubba
      First page: 82
      Abstract: The wastewater reuse is an important measure to face water shortage, thus improving the resilience of agricultural production chains. However, treated wastewater can contain residual organic micropollutants residues that may result in crop contamination. Among edible crops, olive is the most important agricultural product in the Mediterranean region. Methods to assess the contamination of organic micropollutants such as polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in olives are poorly investigated. Given the complexity of olives, this study focused on the development and validation of a method for the simultaneous extraction of PAHs and PCBs from olives, and subsequent analysis by gas chromatography coupled with mass spectrometry detection. Extraction was optimized through a QuEChERS protocol, studying the effect of the extraction solvent (CH2Cl2, cyclohexane, CH3CN) and of the dispersive-solid phase extraction (d-SPE) sorbent (octadecyl silica, Florisil, primary secondary amine, Z-Sep) on the recovery of micropollutants. The best recoveries (94–122%, relative standard deviations below 5%) were obtained using CH3CN/H2O and a double purification step with Z-Sep and Florisil. The method developed for PAHs and PCBs, which showed good intra-day (<2.7%) and inter-day (<2.9%) precision and low matrix effect ( ME < 14%), was applied to the analysis of olives grown by irrigation with reclaimed wastewaters.
      Citation: Separations
      PubDate: 2022-03-21
      DOI: 10.3390/separations9030082
      Issue No: Vol. 9, No. 3 (2022)
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