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enantiomer separation

Yu Ma, Aijie Li, Xiaonan Gao, Fang Huang, Xuan Kuang, Peng Yang, Jieyu Yue, Bo Tang
Metal-organic gel (MOG) matrices with tunable pore sizes ranging from micropore to macropore, derived from microporous metal-organic coordination polymers (PCPs), has attracted great attention for their enhanced pore accessibility compared with the multifunctional PCP materials themselves. The enhanced pore accessibility of chiral MOGs is especially imperative for mass transfer applications, including enantioseparations and purifications. Here, for the first time, a novel hierarchical porous MOG-coated SiO2 , derived from a chiral metal-organic coordination polymer, is employed as chiral stationary phase for effective high-performance liquid chromatography (HPLC) separation of enantiomers...
February 13, 2019: Macromolecular Rapid Communications
Zoltán-István Szabó, Róbert Ludmerczki, Béla Fiser, Béla Noszál, Gergő Tóth
Pressure-assisted stereospecific capillary electrophoresis method was developed for the determination of enantiomeric purity of the antiparkinsonian agent (R)-rasagiline. The optimized method, 50 mM glycine-HCl buffer pH 2.0, supplied with 30 mM sulfobutylether-β-cyclodextrin, at 35°C, applying 12 kV in reversed polarity, and - 8 mbar pressure (vacuum), short-end injection with -25 mbar x 2 seconds, was successful for baseline separation of rasagiline enantiomers (Rs = 3.5 ± 0.1) in a short analysis time...
February 13, 2019: Electrophoresis
Mohammed A Meetani, Rashed H Alremeithi, Muath K Mousa
A sensitive and selective method for detection and quantitation of the enantiomers of 18 synthetic cathinones with tertiary amine structure using HPLC-UV-VIS has been developed. Two chiral columns, Astec Cellulose DMP and Amylose-based Chiralpak AS-H, have been examined separately. Mobile phase composed of hexane, isopropanol and triethylamine (99.0:1.0:0.1) was used under an isocratic elution mode. Three of these compounds were separated simultaneously after being spiked into urine and plasma samples. 2,3-Methylenedioxy pyrovalerone was used as an internal standard for the purpose of quantitation...
February 7, 2019: Journal of Chromatographic Science
Xinzhong Zhang, Xinru Wang, Fengjian Luo, Huishan Sheng, Li Zhou, Qing Zhong, Zhengyun Lou, Hezhi Sun, Mei Yang, Xuan Cui, Zongmao Chen
Penconazole is a typical triazole fungicide with wide use on fruits, vegetables, and tea plants to control powdery mildew. In the present study, an efficient graphite carbon black solid phase extraction (GCB-SPE) purification combined with chiral ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was developed for determination of penconazole enantiomers in different complex matrices, including grape, tea, soil, lotus root, lotus leaf, lotus seed and hulls. The method was then applied to investigate the enantioselective dissipation of penconazole enantiomers in a real field experiment of grape and soil...
February 8, 2019: Ecotoxicology and Environmental Safety
Masashi Harada, Sachise Karakawa, Naoyuki Yamada, Hiroshi Miyano, Kazutaka Shimbo
Novel sophisticated derivatizing agents for the efficient enantioselective separation and mass spectrometric detection of d- and l-amino acids have been developed. Two new axially chiral reagents derived from 6,6'-dimethyl-2,2'-biphenyldiamine were synthesized. Their chiral separation and detection abilities were evaluated by derivatizing proteinogenic amino acid standards in reversed-phase liquid chromatography-tandem mass spectrometry (LC-MS/MS). The resulting diastereomers derived from the developed derivatizing agents and amino acids could be completely separated, because of the effective chiral environment constructed by the axially chiral biphenyl moiety...
January 30, 2019: Journal of Chromatography. A
Jia Wu, Xue Xiao, Zhenqun Li, Li Jia
A method of combining magnetic solid-phase separation (MSPE) and chiral capillary electrophoresis (CE) is developed for enantioseparation of trace amounts of β-blockers. Polynorepinephrine-functionalized magnetic nanoparticles (polyNE-MNPs) are synthesized and applied to simultaneously extract three β-blockers (carteolol, metoprolol, and betaxolol). The prepared polyNE-MNPs are spherical with a diameter of 198 ± 17 nm and the thickness of the polyNE coating is about 14 nm. PolyNE possesses abundant catechol hydroxyl and secondary amine groups, endowing the MNPs with excellent hydrophilicity...
February 8, 2019: Analytical and Bioanalytical Chemistry
Giovanni D'Orazio, Chiara Fanali, Alessandra Gentili, Salvatore Fanali
This work deals with the potentiality of nano liquid chromatography (Nano-LC) for the chiral separation of racemic mixture of tryptophan and some selected derivatives by using 100 μm i.d. fused silica capillary packed with teicoplanin bonded to 5 μm diol silica stationary phase. The experiments were carried out by using a cheap and laboratory-assembled nano-LC - UV system. Elution was done in an isocratic mode using a polar organic mobile phase. In order to find the optimum chiral separation of the studied enantiomers, some chromatographic experimental parameters were systematically studied and optimized...
February 6, 2019: Electrophoresis
Maksim Navakouski, Halina Zhylitskaya, Piotr J Chmielewski, Tadeusz Lis, Joanna Cybińska, Marcin Stępień
Chiral heteroaromatic propellers based on radially π-extended hexapyrrolohexaazacoronenes were obtained in a concise synthesis from suitably functionalized donor-acceptor monopyrroles. To overcome steric hindrance, a new cyclodehydrogenation method was developed, which uses bromine electrophiles as oxidative coupling agents, instead of the commonly employed high-potential oxidants. The new reaction offers high yields of propeller targets even for electron-deficient precursors, and shows electrophile-dependent stereoselectivity, with N-bromosuccinimide and dibromine yielding respectively D6- and C2-symmetric products...
February 4, 2019: Angewandte Chemie
Paola Peluso, Alessandro Dessì, Roberto Dallocchio, Victor Mamane, Sergio Cossu
Liquid-phase enantioseparations have been fruitfully applied in several fields of science. Various applications along with technical and theoretical advancements contributed to increase significantly the knowledge in this area. Nowadays, chromatographic techniques, in particular HPLC on chiral stationary phase, are considered as mature technologies. In the last thirty years, CE has been also recognized as one of the most versatile technique for analytical scale separation of enantiomers. Despite the huge number of papers published in these fields, understanding mechanistic details of the stereoselective interaction between selector and selectand is still an open issue, in particular for high-molecular weight chiral selectors like polysaccharide derivatives...
February 2, 2019: Electrophoresis
Henrik Harnisch, István Ilisz, Ferenc Fülöp, Zsolt Szakonyi, Lóránd Kiss, Antal Péter, Gerhard K E Scriba
The present study investigated the separation of bicyclic β-amino acids with bicyclo[2.2.2]octane, bicyclo[3.1.1]heptane and cyclopenta[d][1,2]oxazole core structures by capillary electrophoresis using native cyclodextrins as well as neutral and charged derivatives as chiral selectors. The amino acids were derivatized with dansyl chloride to provide a UV chromophore. Separations were carried out at 20°C in a 48.5/40 cm, 50 μm fused-silica capillary at an applied voltage of 20 kV. 50 mM sodium phosphate background electrolytes pH 2...
February 1, 2019: Electrophoresis
Xiaodong Sun, Jie Guo, Tao Yu, Yingxiang Du, Zijie Feng, Shiyuan Zhao, Zhifeng Huang, Jie Liu
Magnetic microparticles (MMPs) have been extensively studied and aroused considerable interest in separation science owing to their superior characteristics. In this paper, a novel coated capillary with carboxymethyl-β-cyclodextrin-functionalized magnetic microparticles (CD-MMPs) as stationary phase was constructed and then applied to establish an open-tubular capillary electrochromatography enantioseparation system. The preparation of the CD-MMP-coated open-tubular column was very convenient because the coating of the magnetic microparticles onto the capillary column could be easily manipulated by an external magnetic field...
February 1, 2019: Analytical and Bioanalytical Chemistry
Pius S Fasinu, N P Dhammika Nanayakkara, Yan-Hong Wang, Narayan D Chaurasiya, H M Bandara Herath, James D McChesney, Bharathi Avula, Ikhlas Khan, Babu L Tekwani, Larry A Walker
BACKGROUND: The activity and haemolytic toxicity associated with primaquine has been linked to its reactive metabolites. The reactive metabolites are thought to be primarily formed through the action of cytochrome P450 -mediated pathways. Human erythrocytes generally are not considered a significant contributor to drug biotransformation. As erythrocytes are the target of primaquine toxicity, the ability of erythrocytes to mediate the formation of reactive oxidative primaquine metabolites in the absence of hepatic enzymes, was evaluated...
January 30, 2019: Malaria Journal
Paolo Guglielmi, Simone Carradori, Giulio Poli, Daniela Secci, Roberto Cirilli, Giulia Rotondi, Paola Chimenti, Anél Petzer, Jacobus P Petzer
New N -acetyl/ N -thiocarbamoylpyrazoline derivatives were designed and synthesized in high yields to assess their inhibitory activity and selectivity against human monoamine oxidase A and B. The most important chiral compounds were separated into their single enantiomers and tested. The impact of the substituents at N1, C3 and C5 positions as well the influence of the configuration of the C5 on the biological activity were analyzed. Bulky aromatic groups at C5 were not tolerated. p -Prenyloxyaryl moiety at C3 oriented the selectivity toward the B isoform...
January 29, 2019: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Xiaodong Sun, Yingxiang Du, Shiyuan Zhao, Zhifeng Huang, Zijie Feng
The inner wall of a capillary was coated with glycidyl methacrylate (GMA) to form tentacle-type coating, and poly(glycidyl methacrylate) nanoparticles (PGMA NPs) were then immobilized on the film. Ethanediamine-β-cyclodextrin as chiral selector was covalently bonded into the PGMA NPs through the ring-open reaction. The materials were characterized by SEM, TEM and FT-IR. The modified column was applied to the enantioseparation of the racemates of propranolol, amlodipine and metoprolol. Compared to a capillary with a single layer of CD-PGMA (without GMA coating) and to a CD-GMA system (without PGMA nanoparticles), the performance of the capillary is strongly improved...
January 29, 2019: Mikrochimica Acta
Diogo Montes Vidal, Marcos Antonio Barbosa Moreira, Miryan Denise Araujo Coracini, Paulo Henrique Gorgatti Zarbin
The beetle Homalinotus depressus (Coleoptera: Curculionidae) is a major pest of coconuts in the Northern region of Brazil, for which environmentally friendly methods of control are desired. Behavioral responses of H. depressus to airborne volatile extracts from conspecifics suggested the presence of a male-produced aggregation pheromone. GC analyses of these extracts showed the presence of four male-specific compounds. Analytical data in combination with the synthesis of standards led to the identification of the male-released semiochemicals as epoxyisophorone (1), isophorone (2), homalinol (3), and 2-hydroxyisophorone (4), of which (3) was the major constituent...
January 28, 2019: Scientific Reports
Raquel Pérez-Míguez, Ben Bruyneel, María Castro-Puyana, María Luisa Marina, Govert W Somsen, Elena Domínguez-Vega
A novel analytical method based on hybrid trapped ion mobility spectrometry-time of flight mass spectrometry (TIMS-TOFMS) has been developed to achieve fast enantiomeric separation of amino acids (AAs). Resolution of chiral AAs was achieved by forming diastereomers through derivatization with the chiral agent (+)-1-(9-fluorenyl)ethyl chloroformate (FLEC), avoiding the use of reference compounds. Electrospray ionization (ESI) in positive mode yielded sodiated FLEC-AAs ions of which the diastereomers could be separated by TIMS...
January 25, 2019: Analytical Chemistry
Jiaxi Li, Ruixia Liu, Liyang Wang, Xiaoling Liu, Hongjie Gao
The drug chirality is attracting increasing attention because of different biological activities, metabolic pathways, and toxicities of chiral enantiomers. The chiral separation has been a great challenge. Optimized high-performance liquid chromatography (HPLC) methods based on vancomycin chiral stationary phase (CSP) were developed for the enantioseparation of propranolol, atenolol, metoprolol, venlafaxine, fluoxetine, and amlodipine. The retention and enantioseparation properties of these analytes were investigated in the variety of mobile phase additives, flow rate, and column temperature...
January 24, 2019: Chirality
Shutao Gao, Boyang Tian, Xiangying Zeng, Zhiqiang Yu
RATIONALE: Enantioselective analysis of chiral compounds is an interesting and challenging technique used to elucidate the degradation/transformation mechanisms of these compounds or understand their environmental processes. In this study, we have developed an effective separation and detection approach for the enantiomeric analysis of AHTN and HHCB, as well as a transformation product of HHCB (HHCB-lactone), in sludge samples. METHODS: The analytical method was developed using a cyclodextrin-based enantioselective gas chromatography column combined with tandem mass spectrometry (GC-MS/MS)...
January 22, 2019: Rapid Communications in Mass Spectrometry: RCM
Xiaodong Sun, Kang Liu, Yingxiang Du, Jie Liu, Xiaofei Ma
Recently, chiral ionic liquids (CILs) have received increasing interest in chiral separation by capillary electrophoresis. Nevertheless, the lack of deep perception of the specific mechanism about CILs in CE for enantioseparation still perplexes a legion of researchers, despite the strenuous efforts. In this paper, a lactobionic acid based ionic liquid, tetramethylammonium-lactobionate (TMA-LA) was applied for the first time in CE to establish dual selector system with clindamycin phosphate (CP) for enantiomeric separation...
January 21, 2019: Electrophoresis
Jialiang Guo, Jincai Wang, Hang Lin, Ying Feng, Huanqi Shen, Ruoshi Huang, Lian Liu, Zhixiong Zhao
In order to have deep insights into the mechanisms of enantiomer affinity pattern in both aqueous and non-aqueous systems, an approach combining capillary electrophoresis and molecular modeling was undertaken. A chiral β-blocker, acebutolol, was enantioseparated in aqueous CE and non-aqueous CE using two anionic β-cyclodextrin derivatives. The enantiomer affinity pattern of acebutolol was found to be opposite when an aqueous background electrolyte was replaced with non-aqueous background electrolyte in the presence of heptakis(2,3-di-O-acetyl-6-sulfo)-β-cyclodextrin but remained the same in the presence of heptakis(2,3-di-O-methyl-6-sulfo)-β-cyclodextrin...
January 19, 2019: Journal of Separation Science
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