去甲万古霉素键合手性固定相在反相条件下拆分氨基酸类衍生物

使用合成的大环抗生素-去甲万古霉素键合手性固定相(NVC-CSP),在反相条件下直接拆分了4种丹酰化氨基酸对映异构体,并系统考察了缓冲溶液pH值、有机改性剂用量、温度以及流速对对映体拆分的影响。研究结果表明,在反相条件下,疏水作用和静电作用是影响溶质保留和手性选择性的重要因素,其手性识别的机理类似于蛋白质类手性固定相。     

去甲万古霉素键合毛细管电色谱硅胶整体柱的制备及应用

采用溶胶-凝胶技术制备了具有高机械强度和良好通透性的毛细管硅胶整体柱。以国产大环抗生素去甲万古霉素为 手性选择试剂对所制备的整体柱进行化学衍生,成功地制备了去甲万古霉素键合手性硅胶整体柱。在反相和极性有机相模 式下考察了所制备柱的手性识别能力,并详细考察了流动相条件对分离的影响。研究结果表明,β-受体阻滞剂类药物在极 性有机流动相组成为甲醇-乙腈-乙酸-三乙胺(体积比为80∶20∶0.1∶0.1)时,可获得最佳分离。在反相色谱条件下,电 渗流仍主要由整体硅胶基质材料产生,而手性选择试剂的贡献甚小。在反相色谱条件下,多种不同结构类型的手性药物在 所制备的色谱柱上获得了分离。     

温度对蛋白和β-环糊精手性固定相拆分对映体的影响

 采用三聚氯氰为活化剂分别合成了牛血清白蛋白 (BSA)、人血清白蛋白 (HSA)和 β 环糊精手性固定相 ,研究了温度在色氨酸 ,华法令 ,酮基布洛芬和丹酰化苏氨酸手性拆分中的影响。结果表明 ,在蛋白手性固定相上对映体间的熵变对色氨酸 ,华法令和酮基布洛芬的拆分有很大的影响 ,而丹酰化苏氨酸对映体在 β 环糊精手性固定相上的拆分为典型的焓控过程 ,与蛋白柱有着不同的热力学特性。由于键合方式不同 ,色氨酸在我们合成的BSA手性固定相上的最佳分离温度为 35℃左右 ,而不是文献报道的以戊二醛为活化剂的 2 4℃。     

高效液相色谱使用两种类型的纤维素-三(对甲基苯甲酸酯)固定相手性拆分非洛地平的比较

以高效液相色谱手性固定相法对非洛地平(FEL)进行手性拆分。分别采用两种类型的纤维素-三(对甲基苯甲酸酯)手性柱Chiralcel OJ-R和Chiralcel OJ-H进行比较实验,以正己烷-异丙醇(90:10, v/v)为流动相,考察了流动相、柱温对保留及手性拆分的影响。实验显示,两柱拆分FEL的van’t Hoff图均发生了转折,在高温区域为焓驱动,在低温区域为熵驱动。两柱在温度升高时拆分FEL的分离度均提高,其中OJ-H的分离度优于OJ-R。两种手性柱对FEL具有相似的拆分机理。     

利用“网包法”制备高效液相色谱大环抗生素类手性固定相

万古霉素和替考拉宁都属于糖肽类的大环抗生素，具有立体的环状结构和多个手性中心，是两种常见的手性识别材料，广泛应用于对映体的色谱手性分离分析。该文以万古霉素和替考拉宁为手性选择剂，哌嗪为单体，4，4'-二苯基甲烷二异氰酸酯（MDI）、1，6-己二异氰酸酯（HDI）和2，4-甲苯二异氰酸酯（TDI）为交联剂，通过界面聚合反应形成网状层包裹硅胶载体的方法制得6种高效液相色谱手性固定相，用于分离外消旋化合物，并与MDI直接交联万古霉素和替考拉宁在硅胶表面所得固定相进行了比较。结果表明，利用"网包法"和直接交联法制备的手性柱与商品万古霉素和替考拉宁柱之间具有互补性，均对不同的外消旋体有不同程度的拆分。     

手性薄层色谱评述

根据作者团队近八年的手性薄层色谱文献的再现实验以及进一步研究,从实用性的角度系统总结了手性薄层色谱的9个特点。并且根据作者团队的再现实验结果,介绍了目前的手性薄层色谱报道情况、已有商品手性薄层色谱板的拆分性质及作者团队的万古霉素薄层色谱板的研究。     

氨基酸对映体的手性薄层色谱拆分

设计并制备了３,５－二硝基苯甲酰基取代的β－环糊精薄层色谱键合固定相,用于拆分丹磺酰化氨基酸对映体。该键合相合成方法简单,性能稳定,适用于正相和反相液相色谱。以乙腈－１％（ψ）乙酸三乙胺－乙酸为展开系统,８对丹磺酰化氨基酸对映体得到良好分离,对映异构体之间的相对比移植α为１．１８～１．６３。该文对色谱拆分机理及色谱分离条件进行了较详细的讨论。     

高效液相色谱法对二氢吡喃酮衍生物的手性拆分

介绍了利用手性chiralcel OD和chiralpak AD柱在高效液相色谱上对一系列二氢吡喃酮衍生物进行手性拆分，获得了良好的分离结果，考察了部分对映体在这两种柱上的色谱行为。实验表明手性化合物与手性柱之间存在着化学作用与空间作用，两者的共同作用决定了分离结果。     

去甲万古霉素键合手性固定相拆分β-受体阻滞剂类药物及其结构类似物的研究

以去甲万古霉素为手性选择剂制备了大环抗生素类手性固定相去甲万古霉素键合手性固定相(NVC-CSP)。在极性有机模式下对普萘洛尔、美托洛尔、阿替洛尔及烯丙洛尔等4种β-受体阻滞剂类药物及其结构类似物的外消旋体进行了手性拆分的研究,并考察了流动相组成、酸碱添加剂用量、温度以及流速对分离的影响。研究发现:在此模式下手性物质的保留均随着流动相中甲醇含量的增加而减弱,手性分离因子（α）随着流动相中甲醇含量的增加而升高;随着柱温的升高,大部分溶质在色谱柱上的保留减弱,α值降低;在一定范围内降低流速有利于对映体的分离;     

基于手性共价有机框架材料的气相色谱固定相的合成和分离性能研究

手性共价有机框架材料(CCOFs)在不对称催化、手性识别等诸多领域中具有重要的应用价值,其中,手性分离以其方便、快速和高效的特点成为CCOFs最重要的应用之一。为了进一步开拓CCOFs在色谱手性分离方面的应用,本研究利用后合成修饰法将L-缬氨酸修饰在共价有机框架材料(COFs) TpPa(NH₂)₂上、L-异亮氨酸分别修饰在COFs TpPa(NH₂)₂和TpBD(NH₂)₂上,得到3种CCOFs。将这3种CCOFs分别用作气相色谱手性固定相(CSPs),与聚硅氧烷OV-1701以质量比为3∶7混合配制成4.5 mg/mL的涂渍液,采用动态涂敷法制备了3根毛细管色谱柱进行手性分离分析。研究结果表明,3根色谱柱均具有良好的手性选择性和重复性,可用于氨基酸、醇、醛、酯、醚、酸和酮等25种手性化合物以及正构烷烃、正构醇、芳香族混合物和Grob试剂的快速分离,并且3根柱分离的手性化合物类型具有一定的互补性。3种CCOFs在气相色谱手性分离方面具有较广的手性选择性和...     

Chiral resolution of flurbiprofen and ketoprofen enantiomers by HPLC on a glycopeptide-type column chiral stationary phase

Vancomycin is an amphoteric, glycopeptide, macrocyclic antibiotic. When attached to 5 microspherical silica gel, vancomycin proved to be an effective chromatographic chiral stationary phase that could be used in the reversed-phase mode. In this study, a bonded vancomycin chiral stationary phase (Chirobiotic Vtrade mark) was investigated for the chiral liquid chromatography analysis of ketoprofen and flurbiprofen. The selectivity factor (alpha) and the chiral resolution factor (RS) of Chirobiotic Vtrade mark were evaluated first as a function of the buffer pH and molarity, and second as a function of organic modifier type and composition of the mobile phase. Four organic modifiers (tetrahydrofuran, 2-propanol, 1,4-dioxane and methanol) have been tested for their selectivity. Optimized conditions using 20% of tetrahydrofuran in ammonium nitrate (100 mM, pH 5) were selected for the enantioseparation of flurbiprofen and ketoprofen from their racemic forms. At pH 5, these acidic compounds are almost negatively charged, while the chiral selector possesses a positive charge allowing it to interact electrostatistically with the analytes. Using these chromatographic conditions, the column stability was excellent over several months of experiments.     

手性金属有机笼MOC-PA作为毛细管电泳手性固定相

报道了一种手性金属有机笼[Cu₁₂(L_PA)₁₂(H₂O)₁₂]（PA=L-苯丙氨酸, MOC-PA)作为毛细管电泳分离新型固定相的研究. 采用X射线粉末衍射仪、 红外光谱、 热重分析和扫描电子显微镜对该材料进行了表征, 结果表明该手性金属有机笼具有良好的热稳定性和空间结构. 利用该材料制备的毛细管色谱柱具有良好的手性识别能力, 可拆分1,2-二苯基乙二醇、 佐匹克隆、 4-甲基二苯基甲醇和茴香偶姻等手性药物, 也能拆分位置异构体硝基苯酚. 通过对拆分1,2-二苯基乙二醇、 佐匹克隆、 4-甲基二苯基甲醇和茴香偶姻进行最佳条件的探究, 得出电压、 缓冲溶液浓度及pH值在毛细管电泳中对手性样品分离度的影响. 采用佐匹克隆进行毛细管柱的重现性研究表明, 用该材料制备的毛细管电泳色谱柱具有一定的稳定性和重现性. 可见, 金属有机笼是一种良好的毛细管电泳手性固定相, 有一定的手性拆分能力, 在色谱分离中有较好的发展前景.     

Chiral separation of ketoprofen on an achiral NH<Subscript>2</Subscript> column by HPLC using vancomycin as chiral mobile phase additive

A high-performance liquid chromatographic method for chiral separation of ketoprofen racemate was developed. (R)- and (S)-ketoprofen enantiomers were separated on a LiChrosorb NH₂ column (250 mm × 4.6 mm, i.d 5 µm) at 20 °C, using 2-propanol/potassium dihydrogen phosphate buffer (pH 6.0, 0.05 M) (50:50 v/v). Containing vancomycin as the mobile phase, at a flow rate of 0.8 ml min^?1 and detection wavelength of UV, the detector was set at 310 nm. Under these conditions, ketoprofen enantiomers could be separated with a selectivity factor (α) of 2.172 and a resolution (Rs) of 4.78 using extremely low concentrations of the vancomycin chiral additive.     

万古霉素手性固定相的制备与对映体分离研究

采用双官能团试剂4,4′-二苯基甲烷二异氰酸酯在无水二甲基甲酰胺(DMF)中直接与大环糖肽类抗生素万古霉素及γ-氨丙基硅胶键合,得到环状抗生素手性固定相(CSP)并用于高效液相色谱手性分析。实验结果证实,合成的万古霉素CSP在正相和反相条件下均有一定的拆分能力,其中在反相条件下拆分了17种对映体,显示出其较为广泛的拆分范围,且磷酸缓冲体系略优于三乙胺-乙酸缓冲体系;对一些物质,如D,L-丹酰化氨基酸的拆分有一定的规律,能给出绝对构型信息。所制备的CSP在相体系转化时不发生老化和变性,显示了一定的稳定性。对该CSP的拆分机理进行分析所得到的结果与Armstrong等的分析结果基本一致。     

万古霉素键合固定相的分离性能

万古霉素作为一种大环抗生素,具有复杂的分子结构。在充分考虑万古霉素分子结构特征的情况下,采用戊二醛间隔臂法制备了万古霉素键合固定相,在反相、亲水、离子交换等分离模式下研究了其色谱分离性能。结果表明,当流动相中有机调节剂含量较低时,该色谱柱表现出典型的反相色谱分离模式特征;随着有机调节剂含量的增加,逐渐转变成亲水模式,分离特性发生明显改变。由于万古霉素分子结构中含有可以解离的氨基,因此该固定相也能够用于阴离子交换模式下的分析方法的发展。分别在反相、亲水和阴离子交换模式下,将其应用于扑尔敏等多种非对映体药物和新型甜味剂甜菊糖的高效液相色谱分离;仅通过改变分离条件,即可在3种不同分离模式下完成分离。这些结果可以为新型色谱固定相的设计,以及发展采用特殊结构改性基团的色谱固定相在相应分离模式下的分析方法提供指导。     

Comparison of Separation Efficiency of Macrocyclic Glycopeptide-Based Chiral Stationary Phases for the LC Enantioseparation of β-Amino Acids

Direct reversed-phase high-performance liquid chromatographic methods were developed for the separation of enantiomers of eighteen unnatural β-amino acids, including several β-3-homo-amino acids. The direct separations of the underivatized analytes were performed on chiral stationary phases containing macrocyclic glycopeptide antibiotics such as teicoplanin (Chirobiotic T and T2), teicoplanin aglycone (Chirobiotic TAG), vancomycin (Chirobiotic V and V2), and ristocetin A (Chirobiotic R) as chiral selectors. The effects of the organic modifier, mobile phase composition and pH on the separations were investigated. A comparison of the separation performances of the macrocyclic glycopeptide stationary phases revealed that the Chirobiotic T2 column exhibited better selectivity than the Chirobiotic T column for the separation of β-3-homo-amino acid enantiomers; vancomycin or ristocetin A exhibited lower selectivity. The elution sequence was determined in some cases: the S enantiomers eluted before the R enantiomers, with the exception of the Chirobiotic R column, where the elution sequence R < S was observed.     

以戊二醛为间隔臂的万古霉素键合手性固定相制备

基于戊二醛具有双官能团、高反应活性的特征,以其为间隔臂将万古霉素键合到氨基二氧化硅填料表面,制备了万古霉素键合手性固定相,制备方法简单易行。采用元素分析及扫描电子显微镜对制备的万古霉素键合手性固定相进行了表征。在高效液相色谱分离模式下,分别对谷氨酸、天冬氨酸、苯丙氨酸和异亮氨酸等4种手性氨基酸和手性药物罗格列酮进行拆分,其中谷氨酸和罗格列酮的分离度分别达到了2.0和2.3。系统考察了流动相条件对对映体拆分的影响,证实有机改性剂、缓冲液种类和浓度、pH值及温度对所测样品的保留行为和手性选择性均有显著影响。     

Automated high-performance liquid chromatographic determination of chloramphenicol in milk and swine muscle tissue using on-line immunoaffinity sample clean-up.

An on-line high-performance liquid immunoaffinity chromatographic (HPLIAC) system for the direct determination of chloramphenicol in milk and swine muscle tissue is described. The system consisted of a dual-column system in which an HPLIAC column was directly coupled to an RP-8 high-performance liquid chromatographic column. Skimmed and deproteinated milk or aqueous muscle tissue extract was directly injected into the HPLIAC column. After a washing step with phosphate-buffered saline, chloramphenicol was desorbed by a glycine-NaCl buffer (pH 2.8) and directly concentrated on the RP-8 column. Next, chromatography was carried out using acetonitrile-sodium acetate buffer as the mobile phase. Chloramphenicol was detected at 280 nm. Mean recoveries from spiked raw milk were 70 +/- 2% (1-50 micrograms/kg) and from spiked swine muscle tissue 64 +/- 2% (10-50 micrograms/kg). The calibration curves were linear in the range 1-200 micrograms/kg spiking levels. Limits of determination were 1 microgram/kg for milk and 10 micrograms/kg for muscle tissue.     

Simultaneous, sequential quantitative achiral-chiral analysis by two-dimensional liquid chromatography

In general, chromatographic analysis of chiral compounds involves a minimum of two methods; a primary achiral method for assay and impurity analysis and a secondary chiral method for assessing chiral purity. Achiral method resolves main enantiomeric pairs of component from potential impurities and degradation products and chiral method resolves enantiomeric pairs of the main component and diastereomer pairs. Reversed-phase chromatographic methods are preferred for assay and impurity analysis (high efficiency and selectivity) whereas chiral separation is performed by reverse phase, normal phase, or polar organic mode. In this work, we have demonstrated the use of heart-cutting (LC-LC) and comprehensive two-dimensional liquid chromatography (LC × LC) in simultaneous, sequential achiral and chiral analysis and quantitation of minor, undesired enantiomer in the presence of major, desired enantiomer using phenylalanine as an example. The results were comparable between LC-LC and LC × LC with former offering better sensitivity and accuracy. The quantitation range was over three orders of magnitude with undesired D-phenylalanine detected at approximately 0.3% in the presence of predominant, desired L-phenylalanine (99.7%). The limit of quantitation was comparable to conventional high-performance liquid chromatography. A reversed-phase C18 achiral column in the primary and reversed-phase Chirobiotic Tag chiral column in the secondary dimension were used with a compatible mobile phase.     

万古霉素键合手性固定相高效液相色谱法直接分离泰妥拉唑对映体

利用反相高效液相色谱法在大环抗生素类手性固定相万古霉素键合手性固定相(Chirobiotic V)上直接分离了泰妥拉唑对映体。考察了缓冲溶液的种类、浓度和pH值,有机改性剂的种类和浓度,柱长和柱温等对手性分离的影响。优化后的色谱条件为:Chirobiotic V色谱柱(150 mm×4.6 mm,5 μm),流动相为0.02 mol/L 醋酸铵缓冲液(pH 6.0)-四氢呋喃(体积比为93∶7),流速为0.5 mL/min,柱温为20 ℃,检测波长为306 nm。在此条件下泰妥拉唑对映体达到了基线分离,分离度达1.68;对映体保留时间的相对标准偏差分别为0.48%和0.49%(n=6),峰面积的相对标准偏差分别为0.45%和0.55%(n=6)。所建立的手性分离方法具有简便快速及重复性好等优点。