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1.
A new capillary zone electrophoresis (CZE) method was developed to separate three chiral 2,3-dihydroxy-3-phenylpropionate enantiomers using neutral hydroxypropyl-beta-CD (HP-beta-CD) as chiral selector and borate as background electrolyte. The results showed that HP-beta-CD exhibited good enantioselectivity and high resolution was achieved under the optimum condition of pH 10.3, 200 mM borate buffer containing 6% methanol and 50 mM HP-beta-CD at 15 kV and 20 degrees C within 16 min. The precision of the method was <0.9% for migration time and 4.5% for corrected peak area. In addition, the developed method was successfully applied to the determination of enantiomeric excess (ee) of synthetic 2,3-dihydroxy-3-phenylpropionate samples. With this method, low as 0.2% impurity of the undesirable enantiomer in the presence of high amount of target enantiomer was determined. The results demonstrated that the proposed CZE method is a simple and useful technique and is applicable to ee assay of 2,3-dihydroxy-3-phenylpropionate enantiomers. 相似文献
2.
Nurul Raihana Azhari Noorfatimah Yahaya Faiz Bukhari M. Mohd Suah Samikannu Prabu Boon Yih Hui Mohamad Shariff Shahriman Nur Nadhirah Mohamad Zain Muggundha Raoov 《Chirality》2021,33(1):37-50
A chiral separation method coupled with capillary electrophoresis (CE) analysis for ketoconazole and miconazole enantiomers using chiral selectors such as β‐cyclodextrin (β‐CD) and hydroxypropyl‐β‐CD (HP‐β‐CD) was developed in this study, which included the optimisation, validation and application of the method on the antifungal cream samples. The formation of inclusion complex between the hosts (β‐CD and HP‐β‐CD) and guests (ketoconazole and miconazole) were compared and analysed using ultraviolet–visible spectrophotometry, nuclear magnetic resonance (NMR) spectroscopy and molecular docking methods. Results from the study showed that in a concentration that ranged between 0.25 and 50 mg L?1, the linear calibration curves of each enantiomer had a high coefficient of regression (R2 > 0.999), low limit of detection (0.075 mg L?1) and low limit of quantification (0.25 mg L?1). The relative standard deviation (RSD) of the intraday and interday analyses ranged from 0.79% to 8.01% and 3.30% to 11.43%, respectively, while the recoveries ranged from 82.0% to 105.7% (RSD < 7%, n = 3). The most probable structure of the inclusion complexes was proposed based on the findings from the molecular docking studies conducted using the PatchDock server. 相似文献
3.
Pavel Řezanka David Sýkora Michal Novotný Martin Havlík Vladimír Král 《Chirality》2013,25(11):810-813
Racemic mixtures of six Tröger's base derivatives were separated by chiral nonaqueous capillary electrophoresis. The separation protocol was optimized first for suitable solvents. Then the applicability of various salts dissolved in organic solvents and their mixtures was evaluated. As chiral selectors β‐cyclodextrin and heptakis(2,6‐di‐O‐methyl)‐β‐cyclodextrin at various concentrations were used. The best enantioselectivity for the studied analytes was obtained utilizing formamide as organic nonaqueous solvent containing a mixture of sodium citrate and tris(hydroxymethyl)aminomethane acetate as electrolytes, and β‐cyclodextrin as chiral additive. The experimental results demonstrated the feasibility of nonaqueous capillary electrophoresis for enantioseparation of Tröger's base derivatives. This technique represents a suitable alternative to more commonly used capillary electrophoresis in aqueous environment. Chirality 25:810–813, 2013. © 2013 Wiley Periodicals, Inc. 相似文献
4.
Preparative enantioseparation of four β‐substituted‐2‐phenylpropionic acids was performed by countercurrent chromatography with substituted β‐cyclodextrin as chiral selectors. The two‐phase solvent system was composed of n‐hexane‐ethyl acetate‐0.10 mol L‐1 of phosphate buffer solution at pH 2.67 containing 0.10 mol L‐1 of hydroxypropyl‐β‐cyclodextrin (HP‐β‐CD) or sulfobutylether‐β‐cyclodextrin (SBE‐β‐CD). The influence factors, including the type of substituted β‐cyclodextrin, composition of organic phase, concentration of chiral selector, pH value of the aqueous phase, and equilibrium temperature were optimized by enantioselective liquid–liquid extraction. Under the optimum separation conditions, 100 mg of 2‐phenylbutyric acid, 100 mg of tropic acid, and 50 mg of 2,3‐diphenylpropionic acid were successfully enantioseparated by high‐speed countercurrent chromatography, and the recovery of the (±)‐enantiomers was in the range of 90–91% for (±)‐2‐phenylbutyric acid, 91–92% for (±)‐tropic acid, 85–87% for (±)‐2,3‐diphenylpropionic acid with purity of over 97%, 96%, and 98%, respectively. The formation of 1:1 stoichiometric inclusion complex of β‐substituted‐2‐phenylpropionic acids with HP‐β‐CD was determined by UV spectrophotometry and the inclusion constants were calculated by a modified Benesi‐Hildebrand equation. The results showed that different enantioselectivities among different racemates were mainly caused by different enantiorecognition between each enantiomer and HP‐β‐CD, while it might be partially caused by different inclusion capacity between racemic solutes and HP‐β‐CD. Chirality 27:795–801, 2015. © 2015 Wiley Periodicals, Inc. 相似文献
5.
Tatyana B. Eronina Natalia A. Chebotareva Sergey Yu. Kleymenov Svetlana G. Roman Valentina F. Makeeva Boris I. Kurganov 《Biopolymers》2010,93(11):986-993
The study of the kinetics of thermal aggregation of glycogen phosphorylase b (Phb) from rabbit skeletal muscles by dynamic light scattering at 48°C showed that 2‐hydroxypropyl‐β‐cyclodextrin (HP‐β‐CD) accelerated the aggregation process and induced the formation of the larger protein aggregates. The reason of the accelerating effect of HP‐β‐CD is destabilization of the protein molecule under action of HP‐β‐CD. This conclusion was supported by the data on differential scanning calorimetry and the kinetic data on thermal inactivation of Phb. It is assumed that destabilization of the Phb molecule is due to preferential binding of HP‐β‐CD to intermediates of protein unfolding in comparison with the original native state. The conclusion regarding the ability of the native Phb for binding of HP‐β‐CD was substantiated by the data on the enzyme inhibition by HP‐β‐CD. © 2010 Wiley Periodicals, Inc. Biopolymers 93: 986–993, 2010. 相似文献
6.
Multistage enantioselective liquid–liquid extraction (ELLE) of 2‐phenylpropionic acid (2‐PPA) enantiomers using hydroxypropyl‐β‐cyclodextrin (HP‐β‐CD) as extractant was studied experimentally in a counter‐current cascade of centrifugal contactor separators (CCSs). Performance of the process was evaluated by purity (enantiomeric excess, ee) and yield (Y). A multistage equilibrium model was established on the basis of single‐stage model for chiral extraction of 2‐PPA enantiomers and the law of mass conservation. A series of experiments on the extract phase/washing phase ratio (W/O ratio), extractant concentration, the pH value of aqueous phase, and the number of stages was conducted to verify the multistage equilibrium model. It was found that model predictions were in good agreement with the experimental results. The model was applied to predict and optimize the symmetrical separation of 2‐PPA enantiomers. The optimal conditions for symmetric separation involves a W/O ratio of 0.6, pH of 2.5, and HP‐β‐CD concentration of 0.1 mol L?1 at a temperature of 278 K, where eeeq (equal enantiomeric excess) can reach up to 37% and Yeq (equal yield) to 69%. By simulation and optimization, the minimum number of stages was evaluated at 98 and 106 for eeeq > 95% and eeeq > 97%. Chirality 28:235–244, 2016. © 2016 Wiley Periodicals, Inc. Research highlights are as follows:
- Multistage enantioselective liquid‐liquid extraction is suitable for the separation of 2‐phenylpropionic acid enantiomers with HP‐β‐CD as hydrophilic chiral selector.
- Model predictions of multistage countercurrent centrifugal extraction of 2‐phenylpropionic acid enantiomers are in good agreement with the experimental results.
- Purity for 2‐phenylpropionic acid enantiomers could be remarkably improved by changing W/O ratio or extractant concentration, and or adding the number of centrifugal contact separators.
- Multistage enantioselective liquid‐liquid extraction in centrifugal contactor separators can be hopeful for separations of various enantiomers at a large‐scale.
7.
A new capillary electrophoresis (CE) method has been achieved for simultaneous separation and quantification of phenylalanine, N-acetylphenylalanine enantiomers, and prochiral N-acetylaminocinnamic acid, possibly co-existent in reaction systems or synthesized products of D-phenylalanine. The separation was carried out in an uncoated capillary under reversed-electrophoretic mode. Among the diverse charged cyclodextrins (CDs) examined, highly sulfated (HS)-beta-CD as the chiral selector exhibited the best enantioselectivity. The complete separation of the analytes was obtained under the optimum conditions of pH 2.5, 35 mM Tris buffer containing 4% HS-beta-CD, applied voltage -15 kV, and capillary temperature 25 degrees C. Furthermore, the proposed method was applied to the determination of optical purity and trace impurities in three batches of the asymmetric synthetic samples of D-phenylalanine, and satisfactory results were obtained. The determination recoveries of the samples were in the range of 97.8-103.8%, and precisions fell within 2.3-5.0% (RSD). The results demonstrate that this CE method is a useful, simple technique and is applicable to purity assays of D-phenylalanine. 相似文献
8.
Lucia Burrai Maria Nieddu Maria Antonietta Pirisi Antonio Carta Irene Briguglio Gianpiero Boatto 《Chirality》2013,25(10):617-621
An easy‐to‐prepare chiral CE method for the enantiomeric separation of 13 new amphetamine‐like designer drugs, using CDs as chiral selectors, was developed. Sulfated‐β‐CD was found to be the best chiral selector among the three used (sulfated‐β‐CD, caroboxymethyl‐β‐CD, dimethyl‐β‐CD). The separation of the analytes was achieved in a fused‐silica gel capillary at 20 °C using an applied voltage of +25 kV. The optimized background electrolyte consisted of 63.5 mM H3PO4 and 46.9 mM NaOH in water. Several electrophoretic parameters such as CD type, CD concentration (1 ? 40 mg/mL), buffer pH (2.6, 3.6, 5.0, 6.0), length of the capillary (70 ? 40 cm total length), amount of the organic solvent (methanol and acetonitrile) were investigated and optimized. Chirality 25:617–621, 2013. © 2013 Wiley Periodicals, Inc. 相似文献
9.
Antoni Torrens Jos A. Castrillo Jordi Frigola Leonardo Salgado Jordi Redondo 《Chirality》1999,11(1):63-69
The optical resolution of (±)‐cizolirtine was accomplished with excellent results (>99% ee) by means of crystallization with (+)‐ or (−)‐di‐p‐toluoyltartaric acid. The optical purity of the samples was controlled by three independent methods: 1H NMR, capillary electrophoresis (CE) (using β‐cyclodextrins as chiral resolving agents), and HPLC (using a glycoproteic column). The use of a rapid analytical technique like 1H NMR for estimating the relative amounts of each enantiomer, together with the high sensitivity of CE, afforded a convenient strategy for monitoring the entire process leading to enantiopure compounds. Chirality 11:63–69, 1999. © 1999 Wiley‐Liss, Inc. 相似文献
10.
Janusz Zukowski 《Chirality》1998,10(4):362-363
A HPLC method is described for the chiral analysis of the commercially available Jacobsen's catalyst. A hydroxypropyl β-cyclodextrin stationary phase was used in conjunction with a nonaqueous, polar-organic mobile phase. The method can be applied to control the enantiomeric purity of the catalyst, which is of great importance for quality control of that product. High accuracy in the determination of trace levels of the unwanted enantiomer in the presence of large amounts of the desired enantiomer is demonstrated. Chirality 10:362–363, 1998. © 1998 Wiley-Liss, Inc. 相似文献
11.
Sirantha Perera Yun‐Cheol Na Thomas Doundoulakis Victor J. Ngo Qing Feng Zachary S. Breitbach Carl J. Lovely Daniel W. Armstrong 《Chirality》2013,25(2):133-140
High performance liquid chromatography (HPLC) and capillary electrophoresis (CE) were used to examine the enantiomeric separation of a series of 17 racemic tetrahydrobenzimidazole analytes. These compounds were prepared as part of a synthetic program directed towards a select group of pyrrole‐imidazole alkaloids. This group of natural products has a unique framework of pyrrole‐ and guanidine‐containing fused rings which can be constructed through the intermediacy of a tetrahydrobenzimidazole scaffold. Several bonded cyclodextrin‐ (both native and derivatized) and derivatized cyclofructan‐based chiral stationary phases were evaluated for their ability to separate these racemates via HPLC. Similarly, several cyclodextrin derivatives and derivatized cyclofructan were evaluated for their ability to separate this set of chiral compounds via CE. Enantiomeric selectivity was observed for the entire set of racemic compounds using HPLC with resolution values up to 3.0. Among the 12 different CSPs, enantiomeric recognition was most frequently observed with the Cyclobond RN and LARIHC CF6‐P, while the Cyclobond DMP yielded the greatest number of baseline separations. Fifteen of the analytes showed enantiomeric recognition in CE with resolution values as high as 5.0 and hydroxypropyl‐γ‐cyclodextrin was the most effective chiral additive. Chirality 25:133–140, 2013. © 2012 Wiley Periodicals, Inc. 相似文献
12.
Masatake Akita Yuji Hatada Yuko Hidaka Yukari Ohta Masayasu Takada Yoshinori Nakagawa Koichi Ogawa Teruo Nakakuki Susumu Ito Koki Horikoshi 《Acta Crystallographica. Section D, Structural Biology》2004,60(3):586-587
A γ‐cyclodextrin glycosyltransferase (EC 2.4.1.19) from Bacillus clarkii was crystallized using the hanging‐drop vapour‐diffusion method at 293 K. X‐ray diffraction data were collected to 2.2 Å. The crystal belongs to space group R3, with unit‐cell parameters a = b = 211.6, c = 52.7 Å. The asymmetric unit contains one protein molecule, with a corresponding VM of 3.03 Å3 Da−1 and a solvent content of 59.4%. Molecular replacement was successfully carried out using a homology model based on the three‐dimensional structure of the CGTase from Thermonanaerobacterium thermosulfurigenes EM1 as a search model. 相似文献
13.
Vilanterol trifenatate is a novel chiral long‐acting β2‐agonist developed. Vilanterol combined with inhaled corticosteroids can treat COPD and asthma. A simple liquid chromatographic method is developed for the quantitative determination of R‐vilanterol and S‐vilanterol (impurity S). HPLC separation was achieved on Chiralpak ID (250 × 4.6 mm; particle size 5 μm) column using hexane‐ethanol‐ethanolamine (75:25:0.1, v/v/v) as mobile phase at a flow rate of 1.0 mL/min. The resolution is greater than 3.3. Ethanolamine in the mobile phase is vital to enhance chromatographic efficiency and resolution between the isomers. The method was validated with respect to accuracy, specificity, precision, LOD, LOQ, linearity, and robustness as ICH guidelines. 相似文献
14.
《Chirality》2017,29(9):558-565
Three kinds of sulfated β‐cyclodextrin (S‐β‐CD), including a single isomer, heptakis‐6‐sulfato‐β‐cyclodextrin (HS‐β‐CD), degree of substitution (DS) of 7, which was synthesized in our laboratory and another two commercialized randomly substituted mixtures, a sulfated β‐cyclodextrin with DS of 7 to 11, as well as a highly sulfated‐β‐cyclodextrin with DS of 12 to 15, were used for the enantioresolution of 12 drugs (the β‐blockers, phenethylamines, and anticholinergic agents) in capillary electrophoresis. The enantioseparation under varying concentrations of S‐β‐CD and background electrolyte pH were systematically investigated and compared. Based on the experimental results, the effect of the nature of S‐β‐CD and analyte structure on the enantioseparation is discussed. 相似文献
15.
Yang Yue Shengquan Liu Hongbin Li Binghong Song Ting Xie Yan Sun Yapeng Chao Shijun Qian 《Acta Crystallographica. Section F, Structural Biology Communications》2013,69(10):1186-1189
Improving the specificity of α‐cyclodextrin glucanotransferase is a significant issue in the field of α‐cyclodextrin production. In this study, a constructed Y167H mutant α‐cyclodextrin glucanotransferase with enhanced α‐cyclodextrin specificity was successfully expressed and purified. Single crystals were grown using PEG 4000 as a precipitating agent by the hanging‐drop vapour‐diffusion method at 293 K. The crystals exhibited two kinds of morphology in different crystallization conditions. The crystals diffracted to at least 2.2 Å resolution (space group P212121), with unit‐cell parameters a = 65.69, b = 78.70, c = 137.00 Å. Assuming the asymmetric cell to be occupied by a monomer of 75 kDa, the unit cell contains 43.77% solvent with a crystal volume per protein mass, VM, of 2.19 Å3 Da−1. 相似文献
16.
In this paper, five of six samples of 2,3-allenoic acid enantiomers were separated by capillary zone electrophoresis (CZE) using hydroxypropyl-beta-cyclodextrin (HP-beta-CD) and hydroxypropyl-gamma-cyclodextrin (HP-gamma-CD) as chiral selectors. Using HP-beta-CD for chiral separation, three of the six enantiomers were separated. Five experimental conditions including HP-beta-CD concentration, pH, buffer concentration, temperature, and running voltage were investigated for their influence on separation and migration using enantiomers of 2-methyl-4-phenyl-2,3-butadienoic acid (A) and 2-(n-propyl)-4-phenyl-2,3-butadienoic acid (B) as samples. Good separation results were observed when [HP-beta-CD] = 3-12 mmol/L and pH = 7-9 for samples A and B. The temperature range of 15-25 degrees C can be selected for convenience. According to the chiral separation results, HP-beta-CD and HP-gamma-CD should be valuable selectors to separate 2,3-allenoic acids and HP-gamma-CD was suggested to separate the 2,3-allenoic acid samples with a group at 4-position bulkier than phenyl. 相似文献
17.
A cyclodextrin-modified micellar electrokinetic chromatography (CD-MEKC) technique has been developed for enantioseparation of vinpocetine using an inexpensive 2-hydroxypropyl-β-CD (HP-β-CD) as the chiral selector (CS). The best chiral separation was achieved using 40 mM HP-β-CD as the CS in 50 mM phosphate buffer (pH 7.0) consisting of 40 mM sodium dodecyl sulfate (SDS) at a separation temperature and separation voltage of 25°C and 25 kV, respectively. To the author's best knowledge, this is the first CD-MEKC study able to successfully separate the four stereoisomer of vinpocetine in separation time of 9.5 min and resolution of 1.04-3.87. 相似文献
18.
Hui‐Woog Choe Kyo Sun Park Jrg Labahn Joachim Granzin Cheol‐Ju Kim Georg Büldt 《Acta Crystallographica. Section D, Structural Biology》2003,59(2):348-349
Single crystals of α‐cyclodextrin glucanotransferase isolated from Bacillus macerans have been grown with polyethylene glycol 6000 as a precipitating agent by sitting‐drop vapour diffusion at room temperature. The crystals were suitable for X‐ray analysis and diffracted to at least 2.0 Å (space group P212121), with unit‐cell parameters a = 66.79 (2), b = 79.66 (1), c = 141.16 (1) Å. Assuming the asymmetric cell to be occupied by a monomer of 74 kDa, the unit cell contains 42.6% solvent with a crystal volume per protein mass, VM, of 2.53 Å3 Da−1. 相似文献
19.
The enantiomers of α-phosphonosulfonic acids were completely resolved by capillary electrophoresis using β-cyclodextrin as a chiral selector in a borate electrolyte and HPLC using a chiral AGP column. The methods were used to quantitate the R-enantiomer present as an impurity in the S-enantiomer, a potential cardiovascular drug candiate. Chirality 9:104–108, 1997. © 1997 Wiley-Liss, Inc. 相似文献
20.
A simple high performance liquid chromatography method HPLC‐UV for simultaneous enantiomeric determination of propranolol, metoprolol, pindolol, and atenolol in natural water samples was developed and validated, using a molecularly imprinted polymer solid‐phase extraction. To achieve this purpose, Lux® Cellulose‐1/Sepapak‐1 (cellulose tris‐(3,5‐dymethylphenylcarbamate)) (Phenomenex, Madrid, Spain) chiral stationary phase was used in gradient elution and normal phase mode at ambient temperature. The gradient elution program optimized consisted of a progressive change of the mobile phase polarity from n‐hex/EtOH/DEA 90/10/0.5 (v/v/v) to 60/40/0.5 (v/v/v) in 13 min, delivered at a flow rate of 1.3 ml/min and a sudden change of flow rate to 2.3 ml/min in 1 min. Critical steps in any molecularly imprinted polymer extraction protocol such as the flow rate to load the water sample in the cartridges and the breakthrough volume were optimized to obtain the higher extraction recoveries for all compounds. In optimal conditions (100 ml breakthrough volume loaded at 2.0 ml/min), extraction recoveries for the four pairs of β‐blockers were near 100%. The MIP‐SPE‐HPLC‐UV method developed demonstrates good linearity (R2 ≥ 0.99), precision, selectivity, and sensitivity. Method limit detection was 3.0 µg/l for propranolol and pindolol enantiomers and 20.0 and 22.0 µg/l for metoprolol and atenolol enantiomers, respectively. The proposed methodology should be suitable for routine control of these emerging pollutants in natural waters for a better understanding of the environmental impact and fate. Chirality 24:860–866, 2012. © 2012 Wiley Periodicals, Inc. 相似文献