双水相手性萃取拆分扁桃酸外消旋体

研究了扁桃酸(MA)对映体在含β-环糊精(β-CD)手性选择剂的聚乙二醇(PEG)/(NH_4)_2SO_4双水相体系中的萃取分配行为.考察了pH、PEG和(NH_4)_2SO_4的质量分数、β-CD的浓度、MA的浓度与萃取温度等因素对拆分效果的影响.实验结果表明:双水相手性萃取具有很强的手性分离能力,β-CD对L-MA对映体的识别能力大于对D-MA对映体的识别能力;当温度为30℃、pH=1.0、PEG2000质量分数为30%、(NH_4)_2SO_4质量分数为20%、β-CD的浓度为0.008 mol/L、扁桃酸的浓度为0.05 mol/L时,分离因子(α)达到2.46,上、下相对映体过剩值(e.e.%)分别为42.13%和40.43%.     

高效液相色谱手性流动相添加剂法分离3种黄酮类化合物对映体

采用反相高效液相色谱法(RP-HPLC),以磺丁基醚-β-环糊精(SBE-β-CD)作为手性流动相添加剂,建立了二氢黄豆苷原(dihydrodaidzein)、雌马酚(equol)和山姜素(alpinetin)3种黄酮类化合物的手性拆分方法。考察了环糊精的种类和浓度、有机相的种类和比例、缓冲盐的种类和浓度以及pH对3种化合物手性拆分效果的影响。结果表明:采用Kromasil 100-5C₁₈(250 mm×4.6 mm, 5 μm)色谱柱,流动相为乙腈-10 mmol/L SBE-β-CD水溶液(含20 mmol/L KH₂PO₄, pH值到4.0)(体积比为20:80)的条件下,二氢黄豆苷原、雌马酚和山姜素的对映体都达到了基线分离,分离度分别为1.8, 1.9和1.4。该方法简便,分离效果好,对黄酮类化合物的拆分具有应用价值。     

生物法制备2,3-丁二醇的最新进展

2,3-丁二醇及其衍生物作为重要的液体燃料和化工原料,具有广阔的工业应用前景。高效、经济的2,3-丁二醇生物制备方法,对我国低碳经济和循环经济的建设具有重要的促进作用。针对近三年间生物法制备2,3-丁二醇领域的最新研究成果,本文综述了当前国内外学者在该领域研究的热点,即关键基因和酶的鉴定、新菌种的开发和代谢工程改造、同步糖化和共培养等发酵条件的优化、耦合工艺等分离纯化技术改进等。使用非致病的高产单一2,3-丁二醇手性异构体的代谢工程菌株,作为细胞炼制工厂,利用廉价的非粮原料作底物,采用经济、简单、环保的分离纯化方式,是2,3-丁二醇产业化发展的可靠保障。     

Chiral Monolithic Silica-Based HPLC Columns for Enantiomeric Separation and Determination: Functionalization of Chiral Selector and Recognition of Selector-Selectand Interaction

This review draws attention to the use of chiral monolithic silica HPLC columns for the enantiomeric separation and determination of chiral compounds. Properties and advantages of monolithic silica HPLC columns are also highlighted in comparison to conventional particle-packed, fused-core, and sub-2-µm HPLC columns. Nano-LC capillary monolithic silica columns as well as polymeric-based and hybrid-based monolithic columns are also demonstrated to show good enantioresolution abilities. Methods for introducing the chiral selector into the monolithic silica column in the form of mobile phase additive, by encapsulation and surface coating, or by covalent functionalization are described. The application of molecular modeling methods to elucidate the selector–selectand interaction is discussed. An application for enantiomeric impurity determination is also considered.     

硅胶负载手性氨基醇聚合物的合成及其应用

以L-亮氨酸(L-Leu)为手性源,经酯化、格氏化、酰胺化等步骤制备手性单体(L-NALAA),以该单体为手性识别基团,在引发剂偶氮二异丁腈和交联剂乙二醇二甲基丙烯酸酯(EDMA)的作用下,与烯化功能硅胶发生自由基共聚反应,制备了新型键合硅胶手性固定相,其结构经FT-IR、TGA、EA表征。以4种对映异构体为模型药物对手性材料手性固定相的手性拆分性能进行研究,结果表明,手性材料手性固定相对奥美拉唑和兰索拉唑的拆分效果较好。     

Enantioselective analysis of ofloxacin enantiomers by partial-filling capillary electrophoresis with bacteria as chiral selectors

The enantiomeric separation of ofloxacin enantiomers (OFLX) was achieved by using capillary electrophoresis partial-filled with Escherichia coli, Pseudomonas aeruginosa (Gram-negative), and Staphylococcus aureus (Gram-positive) as chiral selectors. Experimental parameters, including the concentration of background electrolyte, applied voltage, length of the filled bacteria plug, and pH of the buffer, were intensively investigated. Baseline separation of OFLX could be achieved within 7 min by using E. coli and P. aeruginosa as chiral selectors under the following conditions: electrophoretic buffer composed of 10 mM phosphate buffer at pH 7.4, applied voltage at 15 kV, and the bacteria (6.0 × 10(8) cells/mL) were injected into the capillary by gravity with injection height of 17.5 cm for 180 s (E. coli), 300 s (P. aeruginosa), and 300 s (S. aureus), respectively. E. coli and P. aeruginosa had better chiral selectivity for OFLX than S. aureus, which was in good agreement with OFLX having better antimicrobial activity on Gram-negative rather than Gram-positive bacteria. A novel method was developed for the enantioselective separation of enantiomers using bacteria as chiral selectors, which provides a new approach for antimicrobials enantioselective analysis, chiral pharmacodynamics, and chiral pharmacokinetics studies.     

手性流动相添加剂法拆分比索洛尔对映体

以羧甲基-β-环糊精作为手性流动相添加剂,建立了高效液相色谱拆分比索洛尔对映体的方法。系统考察了手性添加剂的种类及浓度、流动相中甲醇的含量、pH值和流速等因素对拆分的影响。色谱分离条件:流动相甲醇∶乙腈∶水为20∶67∶13(V/V/V),羧甲基-β-环糊精浓度为0.5g.L-1,pH值为4.07(以三乙胺-冰乙酸调节),流速为0.3mL.min-1,检测波长223nm,对映体得到基线分离,分离度为1.89。     

Selective response of antigen‐antibody reactions on chiral surfaces modified with 1,2‐diphenylethylenediamine enantiomers

This work reported a comparative analysis of the amperometric responses of antigen‐antibody reactions on two stable chiral surfaces which were modified with 1,2‐diphenylethylenediamine enantiomers. Alpha‐fetoprotein antibody and antigen (anti‐AFP and AFP) were selected as model systems. First, (1R,2R)‐1,2‐diphenylethylenediamine or (1S,2S)‐1,2‐diphenylethylenediamine was modified on the gold surface of the electrode through amide linkage to construct chiral surfaces. Then, anti‐AFP was immobilized on the chiral electrode surface by electrostatic and hydrogen bonding interactions. The electrochemical characteristics of the modified electrodes were studied via cyclic voltammetry. The selective current responses of antigen‐antibody reactions on chiral electrode surfaces for different incubation time and varying AFP concentrations were monitored. The antigen‐antibody reactions were greatly influenced by the chirality of 1,2‐diphenylethylenediamine enantiomers, and the amperometric responses obtained from the (1S,2S)‐1,2‐diphenylethylenediamine modified electrode was obviously stronger than that from the (1R,2R)‐1,2‐diphenylethylenediamine modified electrode. Such work may not only offer valuable reference to the research of chiral drugs, but also help to comprehend the high selectivity of chiral molecular species in biosystems. Copyright © 2011 John Wiley & Sons, Ltd.     

Chiral Recognition of Penicillamine Enantiomers Based on DNA‐MWNT Complex Modified Electrode

Double‐stranded DNA and multiwalled carbon nanotube (MWNT) complex modified glassy carbon electrodes (DNA‐MWNT‐GCE) were employed to discriminate penicillamine (PA) enantiomers. Cyclic voltammetry, electrochemical impedance spectroscopy, atomic force microscopy and ultraviolet‐visible spectroscopy were used to characterize the enantioselective phenomenon. The results indicated that the binding effect between L ‐PA and DNA‐MWNTs was stronger than that of D ‐PA and DNA‐MWNTs. In addition, the influencing factors of the modified electrodes were systematically investigated. The modified electrodes exhibited a linear response towards PA enantiomers from 1.0×10^?1 to 1.0×10^?8 mol L^?1 and detection limits of 3.1×10^?9 and 3.3×10^?8 mol L^?1 for L ‐PA and D ‐PA, respectively.     

手性流动相添加法拆分酮康唑外消旋体

采用C18反相色谱柱,利用在流动相中加入手性选择剂的方法实现酮康唑对映体的拆分。研究了手性选择剂的种类及浓度、流动相pH值、甲醇比例和柱温等因素对酮康唑手性分离的影响,结果表明磺丁基-β-环糊精可以使酮康唑对映体完全分离,最后选择的流动相组成为甲醇-0.02 mol/L磷酸二氢钠(体积比为60∶40,含0.02%三乙胺和1.0 mmol/L磺丁基-β-环糊精,用稀磷酸调节pH值到3.00)。酮康唑对映体在6 min内得到基线分离,分离度为2.05。方法简便,分离效果好,对酮康唑对映体的拆分具有应用价值。