高效液相配体交换色谱法进行氨基酸的光学拆分

本文设计并合成了新型亲水性聚乙烯胺型手性配体高分子络合物,并借助高效液相色谱法进行氨基酸光学拆分。将实验结果进行计算机辅助回归处理,得到一系列描述拆分特性的曲线方程。     

不对称转换在α—氨基酸拆分中的应用

本文综述了不对称转换在α－氨基酸拆分中的应用，参考文献１９篇。     

配位体交换树脂对中性氨基酸分离性能的研究

采用配位体交换树脂对中性氨基酸(Gly,Ala,Val和Leu)进行了分离,并与一般阳离子交换树脂的分离性能进行了比较,对淋洗剂、柱温等分离条件进行了实验;研究了树脂载体结构、功能基及配位中心离子对分离性能的影响。     

用铜（Ⅱ）—L—精氨酸配体交换薄层色谱拆分氨基酸对映体

报道了一种新的配体交换薄层色谱拆分氨基酸对映体的方法。以醋酸铜－Ｌ－精氨酸的络合物为配体交换剂，用浸渍的方法吸附在硅胶薄层板上，制成配体交换薄层，用ＰＲＩＳＭＡ优化法选择出展开剂的最佳组成为：甲醇／乙腈／四氢呋喃／水＝８０：８．２：５．８：６，在此色谱条件下，十对氨基酸对映体得到良好的分离，Ｄ－和Ｌ－氨基酸的相对比移值在１．０９－２．４０之间。文中对配体交换薄层的制备方法，样品的分子结构及色谱行为     

光学活性含硅氨基酸的合成

光学纯的硅取代氨基酸是一类非天然的手性氨基酸合成子，在药物，植物保护 剂和精细化学品的合成具有极为广阔的应用前景，其合成方法包括化学不对称合成 及化学合成外消旋体－生物学拆分两种，综述了该方面的研究进展。     

硅胶键合手性配体交换色谱固定相拆分α-氨基酸

用简易的方法制备了铜(Ⅱ)—L—羟脯氨酸键合手性固定相；在所制备的手性固定相上，用配体交换色谱法研究了pH值、温度、中心离子浓度及流速对α—氨基酸对映体拆分的选择性和分离度的影响，选择了合理的色谱分离条件；结果表明，该固定相在配体交换模式下，可对部分常见氨基酸进行良好分离。     

对映体选择性配体交换膜的制备和DL-氨基酸的拆分

制备了一种新型光学分离膜,即带有Ｌ－脯氨酸手性选择子的交联聚乙烯醇膜,考察了ＤＬ－酪氨酸,ＤＬ－苯丙氨酸和ＤＬ－色氨酸通过膜的对映体选择性渗透性能。发现Ｌ－氨基酸优先透过膜,消旋氨基酸透过膜的对映体拆分机理类似于手性配体交换色谱方法拆分消旋氨基酸的机理,在ＤＬ－氨基酸的对映体选择性膜透过中,对映体选择性吸附着重要的作用。     

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。     

SYNTHESIS OF THE NOVEL CHIRAL POLYMERS WITH MULTIDENTATE LIGAND AND RESOLUTION OF DL-AMINO ACIDS

A new way for synthesizing styrenic type of chiral resins grafting to multidentate ligand has been found. The synthetic scheme is proved to be practical by means of elemental anaysis, IR spectra and metal adsorbility. The resolving power of the new chiral ligand resins coordinated with copper (Ⅱ) as stationary phases has been discussed based on HPLC, and some points of view about the compositions of mobil phase and mechanism of resolution are presented.     

BORONIC ACIDS AS LIGANDS FOR AFFINITY CHROMATOGRAPHY

 A review on the principles and applications of boronic acids as affinity ligands for the chromatographic separation of carbohydrates, nucleic acid components, glycoproteins, and other small biomolecules. The mechanisms of interactions between boronate ligands and analytes are described. Various boronate ligands and supports are discussed. Examples of the use of boronate affinity chromatography for separation of each class of analytes are presented.     

准圆周薄层色谱上行展开的研究

圆周薄层色谱能将样品展开为很细的谱线,具有较高的分辨能力,常用于分析一些难分离的物质。这种色谱方法过去只能采用水平展开方法。我们将普通薄层板修饰成特定形状,用最常见的上行展开法获得近似于圆周薄层的色谱。方法不需要特殊展开装置,应用于皂苷、生物碱的分离鉴定取得很好效果。     

聚硅烷亚芳弹性体的凝胶渗透色谱测量

用简易GPC柱研究了在未知合适的Mark-Houwink 系数的情况下,通过GPC和特性粘度的数据,同时计算出宽分布硅烷亚芳弹性体聚合物的分子量和这种类型聚合物的 Mark-Houwink 系数的方法。装柱填料为多孔硅胶球,理论塔板数 4200—5500块/米以上,塔板高度 0.7—0.9毫米。其分子量分布宽度指数在2左右。素炼后,分子量分布变窄,分子量下降。     

聚丙烯纤维的X衍射曲线的计算分峰法

本文改进了 Hindeleh等的聚合物非晶态X衍射的表征函数,建立了用于研究聚丙烯纤维结构的计算分峰法。实践表明,它能够成功地应用于同时含有α晶态与非晶态或急冷晶态与非晶态等各种类型的聚丙烯纤维的结构研究。     

CONVENIENT SYNTHETIC METHODS FOR THE PREPARATION OF N-FLUOROALKYLHYDROXAMIC ACIDS

ABSTRACT

Polyhydroxamate chelators containing fluoro substituents are of interest as potential extractants for actinides in separations involving supercritical carbon dioxide. In this context, we have developed three new reagents 1, 2, and 3, that allow the efficient incorporation of an N-fluoroalkyl hydroxamate moiety onto a variety of substrates using acylation, alkylation, and Michael addition strategies.     

笼形聚偕胺肟树脂对羧酸的吸附作用

研究了碱处理笼形聚偕胺肟树脂（ＢＣＡＯ）对饱和一元脂肪酸、二元脂肪酸、不饱和脂肪酸、α－取 代乙酸和羟基羧酸的吸附作用。发现ＢＣＡＯ对羧酸强烈吸附。一元羧酸在ＢＣＡＯ上以多分子层吸附占优势,二元和三元羧酸则以单分子层吸附为主要特征;后者作为阴离子聚体吸着在ＢＣＡＯ表面,形成了对外来的羧酸阴离子起排斥作用的离子场。     

BORONIC ACIDS AS MECHANISTIC PROBES FOR THE BACTERIAL LUCIFERASE REACTION

Bacterial luciferase uses long chain aldehydes as substrates. Alkylboronic acid analogs of these substrates with chain lengths of C₇ and C₉ have been synthesized, characterized, and used as mechanistic probes for the light emitting reaction. They behave as inhibitors in the in vitro luminescence reaction. Contrary to an earlier report (Macheroux and Ghisla, 1985, Nachr. Chem. Tech. Lab. 33,785–790) they are not substrates for bacterial luciferase, in that they do not lead to light emission and are not oxidized by the flavin-4a-hydroperoxide to the products boric acid and the corresponding alcohol, as would be expected from a Baeyer-Villiger reaction. However, the particular conformation of a putative boronic acid hydroperoxide at the active center might be such that it would preclude a Baeyer-Villiger fragmentation. Thus, while the results do not support the postulate that luciferase proceeds via a Baeyer-Villiger mechanism, they also do not exclude it. A further observation was that the endogenous light emission (no added aldehyde) decays more rapidly than does the luciferase bound flavin-4a-hydroperoxide. This suggests that the endogenous light is not caused by the decomposition of the flavin-4a-hydroperoxide.     

THERMODYNAMIC ANALYSIS OF THE ENANTIOMER RESOLUTION OF TFA-Ala-OMe, TFA-Ala-Ala-OMe, AND TFA-Ala-Ala-Ala-OMe BY GAS CHROMATOGRAPHY ON CHIRASIL-VAL

TFA-Ala-OMe, TFA-Ala-Ala-OMe, and TFA-Ala-Ala-Ala-OMe can be separated into 1, 2, and 4 enantiomeric pairs, respectively, by GC on the chiral stationary phase Chirasil-Val. The selectivity of the chiral stationary phase for the different stereoisomers is controlled by both interaction enthalpy and interaction entropy. The interaction enthalpy is approximately proportional to the number of Ala units. Although the whole molecule is involved in the interaction, the C-terminus plays an important role. The elution order of DDD- and LLL-TFA-Ala-Ala-Ala-OMe is opposite to the order of the enhalpy values, and the ratio of net retention data t'r(DDD)/t'r(LLL) is increased with increasing temperature. By lowering the temperature, peak crossing of the enantiomeric pair has been observed. Below the isoselective temperature Tiso' the order of elution is ruled by the enthalpy of interaction, above Tiso by the entropy of interaction.     

X-射线衍射计算分峰的多解问题

本文应用电子计算机对聚苯硫醚的X-射线衍射曲线进行计算分峰。发现在一定条件下会出现明显的多解现象,而且对于不同的峰形,不同的峰参数以及不同的晶面来说,多解现象的影响程度都不相同。多解现象的产生与所采用的数理方法以及被研究的对象有关。