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Chiral separation

Hongtao Mu, Zhenlin Xu, Yingju Liu, Yuanming Sun, Baoling Wang, Xiulan Sun, Zhanhui Wang, Sergei Eremin, Anatoly V Zherdev, Boris B Dzantiev, Hongtao Lei
Although stereoselective antibody has immense potential in chiral compounds detection and separation, the interaction traits between stereoselective antibody and the corresponding antigenic enantiomers are not yet fully exploited. In this study, the stereospecific interactions between ofloxacin isomers and corresponding monoclonal antibodies (McAb-WR1 and McAb-MS1) were investigated using time-resolved fluorescence, steady-state fluorescence, and circular dichroism (CD) spectroscopic methods. The chiral recognition discrepancies of antibodies with ofloxacin isomers were reflected through binding constant, number of binding sites, driving forces and conformational changes...
January 5, 2018: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Jiunn-Wei Chen, William Detmold, Joel E Lynn, Achim Schwenk
We show that the empirical linear relation between the magnitude of the EMC effect in deep inelastic scattering on nuclei and the short-range correlation scaling factor a_{2} extracted from high-energy quasielastic scattering at x≥1 is a natural consequence of scale separation and derive the relationship using effective field theory. While the scaling factor a_{2} is a ratio of nuclear matrix elements that individually depend on the calculational scheme, we show that the ratio is independent of this choice...
December 29, 2017: Physical Review Letters
Biao Yang, Qinghua Guo, Ben Tremain, Rongjuan Liu, Lauren E Barr, Qinghui Yan, Wenlong Gao, Hongchao Liu, Yuanjiang Xiang, Jing Chen, Chen Fang, Alastair Hibbins, Ling Lu, Shuang Zhang
Weyl points are the crossings of linearly dispersing energy bands of three-dimensional crystals, providing the opportunity to explore a variety of intriguing phenomena such as topologically protected surface states and chiral anomalies. However, the lack of an ideal Weyl system in which the Weyl points all exist at the same energy and are separated from any other bands, poses a serious limitation to the further development of Weyl physics and potential applications. By experimentally characterizing a microwave photonic crystal of saddle-shaped metallic coils, we observe ideal Weyl points that are related to each other through symmetry operations...
January 11, 2018: Science
Qing Xiong, Jing Jin, Liqiong Lv, Zhisi Bu, Shengqiang Tong
This work deals with the enantioseparation of α-amino acids by chiral ligand exchange high-speed countercurrent chromatography using N-n-dodecyl-l-hydroxyproline as a chiral ligand and copper(II) as a transition metal ion. A biphasic solvent system composed of n-hexane/n-butanol/aqueous phase with different volume ratios was selected for each α-amino acid. The enantioseparation conditions were optimized by enantioselective liquid-liquid extractions, in which the main influence factors, including type of chiral ligand, concentration of chiral ligand and transition metal ion, separation temperature and pH of aqueous phase, were investigated for racemic phenylalanine...
January 11, 2018: Journal of Separation Science
Alessia Ciogli, Omar H Ismail, Giulia Mazzoccanti, Claudio Villani, Francesco Gasparrini
The ever-increasing need for enantiomerically pure chiral compounds has greatly expanded the number of enantioselective separation methods available for the precise and accurate measurements of the enantiomeric purity. The introduction of chiral stationary phases for liquid chromatography in the last decades has revolutionized the routine methods to determine enantiomeric purity of chiral drugs, agrochemicals, fragrances, and in general of organic and organometallic compounds. In recent years, additional efforts have been placed on faster, enantioselective analytical methods capable to fulfill the high throughput requirements of modern screening procedures...
January 10, 2018: Journal of Separation Science
Li Zhou, Shenmeng Jiang, Xue Zhang, Linlin Fang, Xingjie Guo
In this paper, β-cyclodextrin (β-CD) modified gold nanoparticles (AuNPs) coated open tubular column (OT column) was prepared for capillary electrochromatography. The open tubular column was constructed through self-assembly of gold nanoparticles on 3-mercaptopropyl-trimethoxysilane (MPTMS) prederivatized capillary and subsequent modification of thiols β-cyclodextrin (SH-β-CD). Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and ultraviolet visible spectroscopy were carried out to characterize the prepared open tubular column and synthesized gold nanoparticles...
January 10, 2018: Electrophoresis
Rocio Bueno-Perez, Salvador R G Balestra, Miguel A Camblor, Jung Gi Min, Suk Bong Hong, Patrick J Merkling, Sofia Calero
Molecular simulation, through the computation of adsorption isotherms, is a useful predictive tool for the selective capacity of nanoporous materials. Generally, adsorbents are modelled as rigid frameworks, as opposed to allowing for vibrations of the lattice, and this approximation is assumed have negligible impact on adsorption. In this work, we test this approach in an especially challenging system by computing the adsorption of the chiral molecules 2-pentanol, 2-methylbutanol and 3-methyl-2-butanol in the all-silica and germanosilicate chiral zeolites STW, and study their lattice vibrations upon adsorption...
January 5, 2018: Chemistry: a European Journal
Fangjie Guo, Qiaozhi Tang, Jingqian Xie, Lu Zhao, Kai Liu, Weiping Liu
Polychlorinated biphenyls (PCBs) are harmful and persistent organic pollutants that have long been used in industrial manufacturing. Their persistence leads to accumulation in the food chain causing potential toxic effects. As 19 out of 78 of the chiral congeners have stable atropisomers at ambient temperature, we studied some typical enantiomers: PCB45, PCB95, PCB136, and PCB149. The chiral stationary phases OD-H and OJ-H were used for separation in analytic high-performance liquid chromatography (HPLC), as well as for collection in semi-preparative HPLC...
January 8, 2018: Chirality
Imran Ali, Raffat A Khattab, Zeid A Alothman, Ahmad Yacine Badjah, Abdulrahman Alwarthan
The enantiomeric resolution of DL-alanine-DL-tryptophan dipeptide is described on amylose stationary phase. The eluent used was CH3 OH─CH3 COONH4 (10mM)─CH3 CN (50: 40, 10) at 0.8-mL/min flow, 230-nm detection, 25-minute run time, and 25°C ± 1°C temperature. The chiral phase was amylose [AmyCoat RP (15 cm × 0.46 cm × 5 micron)]. The magnitudes of the retention factors (k) were 2.71, 3.52, 5.11, and 7.75. The magnitudes of separation factor (α) were 1.19, 1.57, and 1.51 while the resolution factors (Rs) were 3...
January 8, 2018: Chirality
Narayan Balaji, Suresh P Sulochana, Neeraj Kumar Saini, A Siva Kumar, Ramesh Mullangi
A simple, selective and reliable LC-MS/MS method was validated for simultaneous quantitation of darolutamide diastereomers in 50 μL mice plasma using warfarin as an internal standard (IS) as per regulatory guidelines. Plasma samples were extracted by liquid-liquid extraction and the chromatographic separation was achieved on a Chiralpak IA column with an isocratic mobile phase 5 mM ammonium acetate:absolute alcohol (20:80, v/v) at a flow rate of 1.0 mL/min. Detection and quantitation was done by MRM mode following the transitions: m/z 397 → 202 and 307 → 250 for darolutamide diastereomers and the IS, respectively in the negative ionization mode...
January 8, 2018: Biomedical Chromatography: BMC
Wenting Zhao, Jianzhuang Zhao, Hanqing Zhao, Yueyang Cao, Weitong Liu
A supramolecular solvent composed of decanol in tetrahydrofuran/water was utilized for the simultaneous microextraction of chiral triadimefon and triadimenol in beer samples. Supramolecular solvents are nanostructured amphiphilic liquids that contain aqueous cavities, and the size of those cavities can be adjusted by the ratio of decanol, tetrahydrofuran, and water. The target analytes were mixed into the matrix sample and extracted in the supramolecular solvent phase, which was followed by separation and quantification by chiral liquid chromatography-mass spectrometry...
January 5, 2018: Chirality
Izumi Morita, Hiroyuki Oyama, Yui Kanda, Mayumi Yasuo, Aya Ito, Masahiro Toyota, Yoshinori Hayashi, Takeshi Yokoyama, Norihiro Kobayashi
Ketamine (KT) is a chiral anesthetic agent, (R)- and (S)-enantiomers of which differ in their pharmacological properties. KT has become one of the most commonly used illicit drugs in the world, thus, rapid and feasible on-site testing is required to crack down on the illicit use. Although immunochemical approach with specific antibodies is promising for this purpose, in practice anti-KT antibodies are difficult to obtain. We here disclose generation of monoclonal antibodies against KT. Mice were immunized with either (a) commercially-available or (b) in-house-prepared KT-albumin conjugates...
2018: Biological & Pharmaceutical Bulletin
Natalia Prusinowska, Joanna Szymkowiak, Marcin Kwit
Synthesis and detailed experimental and theoretical study on new urea and thiourea derivatives of chiral trianglamine are presented. In solution, the urea derivative of the trianglamine adopts cone conformation, whereas a respective thiourea derivative exists in solution predominantly as a partial cone conformer. In the crystalline phase, the thiourea trianglamine derivative adapts partial cone conformation. In the solid state, the two symmetry independent molecules of thiourea trianglamine create bilayers, containing molecules arranged in a "zipper" motif...
January 9, 2018: Journal of Organic Chemistry
Jingtang Li, Tao Yu, Guangfu Xu, Yingxiang Du, Zongran Liu, Zijie Feng, Xuan Yang, Ying Xi, Jie Liu
Recently,ionic liquids (ILs) functionalized cyclodextrins (CDs) have attracted more and more attention in the fields of enantioseparation. In this study, a novel IL amino triazolium functionalized β-CD derivative, mono-6-deoxy-6-(4-amino-1,2,4-triazolium)-β-cyclodextrin chloride (4-ATMCDCl), was synthesized for the first time and managed to separate dansyl amino acids and naproxen by capillary electrophoresis (CE). Compared with native β-CD, the new selector exhibited good water solubility and enhanced enantioselectivity...
November 29, 2017: Journal of Chromatography. A
K Hu, H-C Wu
A novel scheme for generating a pair of gigawatt attosecond pulses by coherent Thomson scattering from relativistic electron sheets is proposed. With a circularly polarized relativistic laser pulse, the scattered x-ray signal can have a saddlelike temporal profile, where the lower electromagnetic frequencies are found mostly in the center region of this saddlelike profile. By filtering out the latter, we can obtain two few-attosecond pulses separated by a subfemtosecond interval, which is tunable by controlling the energy of the sheet electrons...
December 22, 2017: Physical Review Letters
Xing Han, Jinjing Huang, Chen Yuan, Yan Liu, Yong Cui
In spite of their great promise for enantioselective processes due to the rich host-guest chemistry, it remains a formidable challenge to construct covalent organic frameworks (COFs) with chiral three-dimensional (3D) structures. Here we report the bottom-up synthesis of the first example of 3D chiral COFs by imine condensation of an enantiopure twofold symmetric TADDOL-derived tetraaldehyde with a tetrahedral tetra(4-anilyl)methane. After post-synthetic oxidation of imine linkages, the framework is transformed into an amide-linked COF with retention of crystallinity and permanent porosity as well as enhanced chemical stability...
January 5, 2018: Journal of the American Chemical Society
Liudmila L Mazaleuskaya, Ashkan Salamatipour, Dimitra Sarantopoulou, Liwei Weng, Garret A FitzGerald, Ian A Blair, Clementina Mesaros
The biosynthesis of eicosanoids occurs enzymatically via lipoxygenases (LOXs), cyclooxygenases (COXs), and cytochrome P450, or through non-enzymatic free radical reactions. The enzymatic routes are highly enantiospecific. Chiral separation and high sensitivity detection methods are required to differentiate and quantify enantioselective HETEs (hydroxy-(5Z,8Z,11Z,13E)-eicosatetraenoic acids) in complex biological fluids. We report here a targeted chiral lipidomics analysis of human blood using ultrahigh performance liquid chromatgraphy (UHPLC)-electron capture atmospheric pressure chemical ionization/high resolution mass spectrometry (ECAPCI/HRMS)...
January 4, 2018: Journal of Lipid Research
Yating Sun, Jingtang Liu, Lei Li, Chi Gong, Shuping Wang, Fan Yang, Huiming Hua, Houwen Lin
Two new butenolide derivatives (±)-asperteretal D ((±)-1) and asperteretal E (2) containing rare 2-benzyl-3-phenyl substituted lactone core, together with nine known analogues (3-11) were obtained from a fungus Aspergillus terreus derived from the marine sponge Phakellia fusca. All the structures were elucidated on the basis of extensive NMR spectroscopic data. The chiral chromatography analyses allowed the separation of the (±)-asperteretal D, of which the absolute configurations were determined by comparing the experimental to calculated electronic circular dichroic (ECD) spectra...
December 22, 2017: Bioorganic & Medicinal Chemistry Letters
Andy Tran, Wadood Y Hamad, Mark J MacLachlan
The self-assembly process in cellulose nanocrystal (CNC) film formation was studied as a function of evaporation time. It is known that the total evaporation time of CNC dispersions affects the structure of the film obtained, but the extension of different phases of the evaporation has not been explored. By extending the evaporation time of CNC suspensions after the onset of liquid crystallinity, the homogeneity of the resulting films could be improved as observed by polarized optical microscopy and scanning electron microscopy...
December 29, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Kian Kadkhodaei, Lisa Forcher, Martin G Schmid
New psychoactive substances are defined as compounds with consciousness-changing effects and have been developed simultaneously with classical drugs. They arise through structural modifications of illegal substances and are mainly produced to circumvent laws. Availability is simple, since new psychoactive substances can be purchased from the Internet. Among them many chemical drug compound classes are chiral and thus the two resulting enantiomers can differ in their effect. The aim of this study was to develop a suitable chiral high-performance liquid chromatography separation method for a broad spectrum of new psychoactive substances using cellulose tris(3,5-dichlorophenylcarbamate) as a chiral selector...
December 27, 2017: Journal of Separation Science
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