单分散树脂键合手性配体交换色谱固定相拆分DL-氨基酸

以单分散交联聚甲基丙烯酸环氧丙酯-甲基丙烯酸乙二醇双酯(PGMA/EDMA)树脂为基质合成了L-脯氨酸键合手性配体交换固定相,并用于DL-氨基酸的直接光学拆分,考察了流动相pH值、金属离子浓度、流速及温度等因素对DL-氨基酸对映体拆分的影响。结果表明,该固定相在配体交换色谱模式下可对多对DL-氨基酸进行良好的拆分。     

新型手性配体交换色谱固定相的制备及应用

 合成了 2 -(2 -羟基 -3 -烷氧基 )丙基 -(S) -1 ,2 ,3 ,4-四氢 -3 -异喹啉羧酸手性选择子 ,制备了两种新型涂渍手性配体交换色谱固定相 ,拆分了某些 DL-氨基酸 ,比较了 DL-氨基酸在两种手性相上的色谱分辨。     

一种新型手性配体交换色谱键合固定相

采用气相或液相色谱法拆分氨基酸对映体通常一化过程,费时而麻烦,而且有可能发生消旋,影响分析结果,手性配体交换色谱法是拆分氨基酸和羟基酸对映体的一种有效方法,其选择性高,不需柱前衍生。Davankov等对此方法进行了评述。此法大都采用刚性环状结构的光活性脯氨酸或羟基脯氨酸键合相作为柱填料,Jeanneret-Gris等曾采用1,2,3,4－四氢－3－异喹啉羧酸接枝的聚丙烯酰胺相拆分氨基酸对映体。     

原子转移自由基聚合技术制备新型手性配体交换色谱固定相及对手性化合物的拆分

采用原子转移自由基聚合(ATRP)技术, 以溴代硅胶为引发剂, CuCl/2,2'-联吡啶(Bpy)为催化体系, 水为溶剂, N-丙烯酰基-L-脯氨酸为单体, 室温下在硅胶表面进行聚合反应, 制得硅胶接枝聚N-丙烯酰基-L-脯氨酸分子刷. 通过改变ATRP反应体系中单体的量, 制备了3种不同键合量且键合量可控的手性配体交换色谱固定相, 利用元素分析和热重分析对其进行表征. 考察了配体接枝率、 流动相Cu²⁺浓度、 pH值和柱温等对DL-氨基酸和α-羟基酸拆分的影响, 优化了色谱分离条件, 探讨了拆分过程的热力学. 结果表明, 所合成的手性配体交换色谱固定相能够分离9种DL-氨基酸和α-羟基酸, 其中DL-酪氨酸、 DL-色氨酸和DL-苏氨酸3种氨基酸可同时进行拆分, 且拆分过程由熵控制.     

Chiral Polymers and Optical Resolution: Investigation of the Mechanism of Ligand Exchange for Resolution of DL-Amino Acids

Abstract

Using novel class chiral ligand polymers which have different chemical environment in chiral cavity, we investigated their functional properties of chiral recognition for DL-amino acids and discussed ligand exchange chromatography of DL-amino acids on different chromatographic conditions in detail.     

L-苯丙氨酸键合手性配体交换色谱固定相的制备及手性拆分

合成了L-苯丙氨酸键合手性配体交换固定相，用元素分析和红外光谱对固定相进行了表征；该固定相在反相条件下对DL-氨基酸对映体有良好的拆分能力。     

LIGAND EXCHANGE RESIN FOR AMINO ACID RECEMATES

Hydrophilic ligand exchange complexes with different chemical environment in chiral cavity were prepared and used as stationary phases of HPLC to resolve DL-amino acids.The mechanism and models of resolution were studied.     

L-羟基脯氨酸键合手性配体交换色谱固定相的制备及手性拆分

合成出了L—羟基脯氨酸键合手性配体交换固定相，用元素分析和红外光谱对固定相进行了表征。该固定相在反相条件下，以水作流动相，对DL—氨基酸对映异构体有良好的拆分能力。     

原子转移自由基聚合技术制备L-苯丙氨酸手性配体交换色谱固定相及其对手性化合物的拆分

在室温条件下,以甲基丙烯酸环氧丙酯(GMA)为单体,溴异丁酰溴为引发剂,CuCl/2,2′-联吡啶(Bpy)为催化剂,通过原子转移自由基聚合(ATRP)反应,将甲基丙烯酸环氧丙酯聚合在硅胶表面。然后再将L-苯丙氨酸共价键合在硅胶表面的聚合物上,制备了新型手性配体交换色谱固定相,并用该固定相对DL-氨基酸进行分离。用元素分析对其进行了表征;详细考察了固定相的合成过程以及流动相pH值、流动相铜离子浓度、柱温等色谱条件对DL-氨基酸对映体拆分的影响。元素分析得出该固定相表面L-苯丙氨酸接枝密度达到4.32 mg/m2;在手性配体交换分离模式下,流动相为0.05 mol/L KH2PO4-0.1 mmol/L Cu(Ac)2水溶液、流速为1.0 mL/min、柱温为50 ℃和检测波长为223 nm条件下,该色谱固定相可以分离DL-天冬氨酸、DL-天冬酰胺等。同时,流动相pH值、铜离子浓度以及柱温对手性对映体的拆分有较大影响。与传统的在硅胶表面直接键合L-苯丙氨酸制得的固定相相比,所合成的固定相接枝密度高,分离效果好,对DL-天冬氨酸及DL-天冬酰胺实现了基线分离。结果表明,在手性配体交换分离模式下,固定相具有良好的拆分性能。     

硅胶键合手性配体交换固定相键合量对α-氨基酸拆分的影响

 合成了两种不同键合量的L 脯氨酸硅胶键合手性配体交换固定相 ,装柱后利用配体交换法分离了一系列的α 氨基酸。实验结果表明键合量不同的固定相对α 氨基酸的拆分能力差别较大。     

中心金属离子及温度对手性识别能力的影响

讨论了用手性配体交换色谱方法拆分离氨基酸时,手性配体、中心离子以及温度对拆分效果的影响。发现采取升高温度和变换中心金属离子的方法,可改善第二个色谱峰的拖尾现象。     

L-异亮氨酸型配体交换固定相对DL-氨基酸的拆分研究

用自制的新型L-异亮氨酸配体交换固定相在配体交换模式下对11种DL-氨基酸进行了拆分研究,详细考察了流动相中铜离子浓度、甲醇含量、流速及温度对拆分效果的影响,并探讨了可能的拆分机理。研究结果表明:流动相中高浓度的铜离子不利于DL-氨基酸的拆分;增加流动相中甲醇的含量,降低流动相流速以及提高色谱柱温度均可改善拆分效果。     

L-半胱氨酸衍生物配体交换手性色谱固定相

应用密闭微波萃取装置对芦荟中的有效成分芦荟甙进行了微波萃取研究,并利用透射电子显微镜对微波萃取机理进行了初步探讨,讨论了不同萃取剂、溶剂浓度、萃取时间和微波功率等对提取率的影响,在萃取剂为乙醇-水体系,溶剂（乙醇）体积分数为70％、萃取时间为4min及微波功率为340W的条件下,萃取效果最佳,与索氏提取及超声波萃取法相比,本法具有萃取速度快、提取率高及溶剂用量少等特点。     

Electrochromatographic enantioseparation using chiral ligand exchange monolithic sol-gel column

This paper describes the development of a monolithic sol-gel column modified with l-hydroxyproline as a ligand exchange chiral stationary phase. It has been demonstrated that the monolithic chiral stationary phase can be used for the enantioseparation of dansyl amino acids, free amino acids, hydroxy acids, and dipeptides by capillary electrochromatography and micro-liquid chromatography. The recommended mobile phase was acetonitrile/0.50 mM Cu(Ac)₂-50 mM NH₄Ac (7:3) adjusted to pH 6.5. The characteristics of the monolithic column using hydroxyproline as chiral selector in CEC have been discussed.     

新型L-羟脯氨酸聚合物键合手性固定相的制备及对手性化合物的拆分

以单分散亲水性交联聚甲基丙烯酸环氧丙酯-甲基丙烯酸乙二醇双酯(PGMA/EDMA)树脂为载体,制备新型L-羟脯氨酸聚合物键合高效手性配体交换固定相。该固定相在配体交换分离模式下,以0.2mol/LNaAc和0.1mmol/LCu(Ac)2水溶液(pH5.2)为流动相,柱温为30℃～50℃,对衍生和非衍生的D,L-氨基酸和α-羟基酸等9种手性化合物进行了高效液相色谱拆分。详细考察了流动相pH值、温度、流速和进样量对手性分离的影响,选择了合适的色谱分离条件。结果表明,所拆分的9种手性化合物,有5种手性化合物能得到基线分离,最好的分离因子α=2.32。     

Direct chiral resolution of underivatized amino acids on a stationary phase dynamically modified with the ion‐exchanger Nτ‐decyl‐l‐spinacine

Increasing attention has been devoted in the last decades to chiral chromatography, principally to high‐performance liquid chromatography techniques using a chiral stationary phase. Many chiral high‐performance liquid chromatography columns are commercially available, but, unfortunately, they are most often rather expensive. A cheap alternative to the commercial chiral columns is the dynamic‐coating procedure of a standard achiral stationary phase with a chiral selector containing both a chiral domain and a chain or a group able to tightly (but noncovalently) bind the achiral support. This is the case of N^τ‐decyl‐l ‐spinacine, already successfully employed to dynamically cover a reversed‐phase column to separate racemic mixtures of amino acids through the ligand‐exchange mechanism. In the present work, the same chiral selector is employed to separate racemic mixtures of amino acids and oligopeptides, in the absence of metal ions: no coordination complex is formed, but only electrostatic and weak nonbonding interactions between the chiral phase and the analytes are responsible for the observed enantioselectivity. The new method is simpler than the previous one, very effective in the case of aromatic amino acids and oligopeptides and also suitable for preparative purposes.     

手性有机磷化合物液相拆分的研究进展

 综述了近年来手性有机磷化合物液相拆分的研究进展。对间接拆分和直接拆分法,特别是各类手性固定相法在拆分有机磷化合物中的应用作了介绍,探讨了相应的拆分机理。85篇。     

Last ten years (2008–2018) of chiral ligand‐exchange chromatography in HPLC: An updated review

Chiral ligand‐exchange chromatography is one of the elective strategies for the direct enantioresolution of small chelating compounds: amino acids, diamines, amino alcohols, diols, small peptides, etc. Unlike other methods, the interaction between chiral selector and analyte enantiomers is mediated by a cation, thus producing diastereomeric ternary complexes. Two main approaches are conventionally applied in chiral ligand‐exchange chromatography. The first relies upon chiral stationary phases where the chiral selector is either covalently immobilized or physically adsorbed onto suitable packing materials (coated phases). In the second approach, chiral molecules are added to the eluent, thus generating chiral eluent systems. Among the advantages of chiral ligand‐exchange chromatography, the generation of UV/vis‐active metal complexes, and the use of commercially available or easy‐to‐synthesize chiral selectors, in combination to rather inexpensive achiral columns for coated phases and chiral eluents, are noteworthy. Besides amino acids and amino alcohols, other species have proven suitable for chiral ligand‐exchange chromatography applications. Recently, the use of either chiral ionic liquids or micellar liquid chromatography systems as well as the successful off‐column formation of diastereomeric complexes have expanded the selectivity profiles and application fields. All of these issues are touched in the review, shedding light to the contributions appeared in the last decade.     

Enantioseparation of a novel “click” chemistry derived native β-cyclodextrin chiral stationary phase for high-performance liquid chromatography

A novel native β-cyclodextrin chiral stationary phase was prepared via “click” chemistry with cuprous iodide–triphenylphosphine complex as the catalyst and applied for enantioseparation of Dns-amino acids, substituted phenyl and phenoxy group modified propionic acids, flavonoids, and some pharmaceutical compounds such as nimodipine, propranolol, brompheniramine and bendroflumethiazide in reversed-phase high-performance liquid chromatography. The studied analytes could be resolved under different separation conditions. The resolution of Dns-DL-Leu could reach 5.08 using a mobile phase consisting of 1% (w/w) triethylammonium acetate buffer (pH 4.11) and methanol (50:50 v/v). The effects of buffer pH and the content of organic modifier on enantioseparation of Dns-amino acids by this novel chiral phase were being investigated. The separation results demonstrate that click chemistry, a versatile reaction, affords a facile approach towards the preparation of stable chiral stationary phases.     

Enantioseparation of Dencichine and D-Isomer on L-Cysteine Derivative Phase by Ligand-exchange Chromatography

Dencichine (β-N-oxalyl-L-α, β-diaminopropionic acid, L-ODAP), a nonprotein amino acid, is a haemostatic agent present in important Chinese medicinal herbs such as Panax notoginseng, as well as other Panax species1. It was first isolated from the seeds …