三角形层析法是一种分离效果较好的层析方式

薄层层析中,如何缩短层析时间,改善Rr值较大化合物的分离效果,减少层析过程中的斑点扩散.提高检出灵敏度等问题,是薄层层析中急待解决的。 近来,我们针对薄层层析工作中存在的上述问题.采用三角形层析法进行实验.结果表明:三角形层析法方法简单,能缩短层析时间.提高检出灵敏     

自制含硅胶滤纸在生化分子层析中的应用

目前,纸层析与薄层层析是微量物质分析分离中最常用的技术。近二十年来,尽管有关纸层析的报道比薄层层析相应减少,也有人预言薄层层析将会取代纸层析,但也有学者持有不同看法,认为纸层析在使用上既经济又方便的特色不能抹煞,并指出它很有发展前途。其中之一就是将纸层析与薄层层析二者结合起来,含硅胶的层析滤纸(以下简称硅胶纸)的应用就     

棒色谱技术的应用

自从1903年Tswett创立液体柱色谱以来,它在有机化学和生物化学中得到了广泛的应用。目前,有机物质的分离提纯仍然以柱色谱为主要手段。与薄层层析相比,柱层析的分离效果较差,操作时间长,溶剂耗费量大。因而促使人们寻找一种分离效果与薄层层析相当而又能作为制备的分离方法。于是发展了制备型薄层层析技术,但分离的最大量只有几百毫克。近来,国外又将吸附剂压制成条,形成制备色谱柱,但这样的柱价格昂贵,尚未得到广泛使用。我们在此基础上建立了棒色谱,并使它得到了实际应用。     

胆汁酸的薄层层析——数理统计法用于层析溶剂系统的选择

本文选择氯仿、乙醇、乙酸乙酯、醋酸和水等五种溶剂作为胆汁酸薄层层析的展开剂,采用正交设计法[L_(16)(4~5)]安排实验,对胆固醇、胆酸、脱氧胆酸、甘氨胆酸、甘氨脱氧胆酸、牛磺胆酸、牛磺脱氧胆酸和卵磷脂等八种化合物的R_f值及层析谱斑点的集中情况,用直观分析和方差分析法处理,得到了单向一次薄层层析全部分离胆汁的溶剂系统,较文献报道方法为佳。     

三七皂甙的离心薄层层析分离—单体皂甙Rg1、Rb1、Re的分离提纯

离心薄层层析法较经典柱层析法分离周期短,效果好,不仅可节省溶剂、固定相,尤其可节省大量时间。这种方法对小量纯品需求者是有效的分离提纯手段。 已知三七皂甙主要成分与人参皂甙相同。人参叶总皂甙的离心薄层层析分离已有报导,作者用含Na_2C_2O_4固定相的分配层析板分离三七皂甙,对梯度洗脱作了较深入研究,取得较好效果。     

薄层层析烧结板的制作与应用

薄层层析是一种现代快速、微量分离技术,由于它具有工具简单、速度快、费用省、分离效果好、灵敏度高等优点,因此近十多年来发展非常迅速,在化工、生化、药物以及天然物的提取和鉴别、无机离子分离等领域中得到广泛应用。薄层层析是通过玻璃板上附着的一层吸附剂经过液体溶剂的流动,由于混合物各组分吸附力的不同而进行分离。但是,薄层的制作对初学者常常感到麻烦,有些制好的薄层往往容易脱落,不便携带,尤其在野外操作特感不便,对需要长期保存的层析图谱也不好保     

用P507体系进行薄层层析法分辨稀土元素

在分离稀土元素的薄层层析法中,展开剂的选择为主要研究课题。1964年,Pierce等用 P204进行稀土元素的薄层层析分离,可分离3—4个稀土元素。1976年以来,德国Specker等人用乙醚-四氢呋喃-?204-硝酸(100:15:1:3.5)在硅烷化的硅胶板上实现     

析相液—液萃取法

析相液—液萃取法是基于胶束水溶液中的析相(Phase Separation)法,国内外已有不少研究报告发表,本文就此题作论述,以了解其发展的概貌及趋向。 析相液—液萃取法有形成凝聚体的析相法和“浊点”析相法两种。 1 形成凝聚体的析相法 形成凝聚体的作用,发生于某些物质的离子在带电荷的表面活性剂(如季铵盐阳离子)或其它物质的水溶液。开始时,这种物质的离子与胶束聚合成业微观的晶簇,接着聚合成显微滴,再进一步凝聚。这些显微滴能以富含表面活性剂的连续相析出,因此,形成两个明显的相。当再加入适当电解质时,富含表面活性剂的相能沉淀或絮凝析出。除了阳离子和阴离子表面活性剂外,蛋白质、高聚物和微乳液也有形成凝聚体的行为。Dubin等根据表面电荷的不同,用来分离血红蛋白质,较详细研究了牛血清蛋白或核糖核酸酶与阳     

蒽醌磺酸盐的高效液相色谱分离及其定量测定

2,6-蒽醌二磺酸盐是GCN士林黄染料中间体,它由蒽醍磺化而成,由于磺化过程中还能生成2,7-蒽醌二磺酸盐及其它异构体,影响产品质量。以往在染料中间体分析中常采用薄层层析和纸层析作为分离手段,但分析速度慢,分离效率较差。据文献报道,高效液相色谱对于蒽醌磺酸盐的分离和分析得到有效应用。     

无机分析中薄层层析法的进展

薄层层析法是近年来在分析化学中发展起来的微量、快速和简易的分析法。其操作是以玻璃板为载体,均匀地涂上所需要的吸附剂(如硅胶、淀粉、交换剂等),然后按纸层析的一般操作方式进行物质的分离、检定和测定。这一方法现在在有机分析中已成为有效的工具,这是由于该方法快速,灵敏度较高,操作简便,受温度及其他条件的限制较小,且与其他方法结合亦可进行定量测定所致。但到目前为止,在无机分析方面的工作还研究得很不够。本文仅就国内外关于薄层层析在无机分析中的工作作     

AN ULTRASENSITIVE BIOASSAY FOR THE DETECTION OF FUROCOUMARINS AND OTHER PHOTOSENSITIZING MOLECULES

Abstract— A photobiological assay based upon inhibition of growth in the DNA repair-deficient bacterium E. coli B _s-1, is described for the analysis of a number of photosensitizing agents. The lower limits of detection were as follows: psoralen 5 × 10^-11g; 5-methoxypsoralen 1 × 10^-9 g; 8-methoxypsoralen 1 × 10^-9 g; 4,5',8-trimethylpsoralen 1 × 10-¹¹ g; angelicin 5 × 10^-9 g; 5,7-di-methoxycoumarin 1 × 10^-7 g; isoimperatorin 5 × 10^-9 g; dictamnine 1 × 10^-8 g; oxypeucedanin 5 × 10^-7 g; 5-nitroxanthotoxin 5 × 10^-7 g; and α-terthienyl 1 × 10^-6 g. All active compounds with the exception of α-terthienyl were more easily detected by several orders of magnitude by E. coli B _s-1 than with the normal wild type E. coli. 5—Geranoxypsoralen and isopimpinellin were not active. The application of this technique, after TLC, to the analysis of complex mixtures from lemon oil, oil of bergamot, Heracleum lanatum, Angelica dawsonii , and celery and parsnip is illustrated. The bioassay described is more rapid and sensitive than previously published methods, permits replica plates to be made, and allows tentative identification of the photosensitized molecular target.     

薄层色谱法在定量分析中的应用

对薄层色谱的定量方法，即目测法，斑点面积法，洗脱法及扫描法作了简要介绍；对1998-2000年薄层色谱法在医药，食品及其他领域定量分析中的应用进行了综述。     

PLS方法辅助TLC/FID技术测定石油沥青的族组成

测定了不同来源的渣油、不同改性工艺沥青的薄层色谱图，提取了谱图特征变量，以偏最小二乘方法为数学工具，通过经典柱色谱法取得基础数据，建立渣油沥青的薄层色谱(TLC)-族组成模型。采用该模型预测待测样品的族组成，并与经典柱色谱法的测定结果相比，饱和烃质量分数、芳烃质量分数和胶质质量分数的相关系数分别为0．9765，0．9901和0．9937。测定结果与经典柱色谱法的测定结果相一致。     

THE SYNTHESIS OF A NEW TYPE OF DISINFECTANT RESIN AND ITS ANTIBACTERIAL ACTIVITY

Polymer supported alkyl dimethyl benzyl ammonium chloride resin disinfectant used for the disinfection of drinking water has been synthesized,and its antibacterial activities have been determined,compared with the commercially used triiodine disinfectant resin.The resin disinfectant was generated successfully when use the combination of surface active agents and ultrosonic.     

1,1-二苯基乙烯存在下无皂乳液聚合制备磁性复合微球

报道了一种制备磁性复合微球的方法——DPE法.在自由基控制剂1,1-二苯基乙烯(DPE)存在条件下,甲基丙烯酸甲酯(MMA)与丙烯酸(AA)发生无皂乳液聚合,制备能与Fe3O4粒子相螯合的活性短链共聚物,加入Fe3O4粒子把短链共聚物引到其表面,引发其它单体继续在Fe3O4粒子表面聚合,制备磁性复合微球.研究了AA、DPE、引发剂及Fe3O4粒子加入量等对制备磁性复合微球的影响.并在此基础上,对优化后工艺制备的磁性复合微球进行了TEM、TGA及磁响应性表征.结果表明,利用该新的方法制备出了磁含量为20%、比饱和磁化强度为32.2emu/g、平均粒径为265nm且表面不含任何杂质的磁性复合微球.     

Biological and chemical detections in adsorbent layer for monitoring microbial production of primycin

Primycin is a macrolide antibiotic complex produced in microbiological fermentation processes. The microbial production of primycin requires an in-process analytical method suitable for monitoring the level of the active agents. In this paper, a method fulfilling the described requirement is presented. This method consists of a simple, efficacious extraction step, an instrumental sample application followed by a high-performance thin-layer chromatographic separation in relatively short time and a quantitative chromatogram evaluation. A dipping technique, in a solution containing sulfuric acid followed by heating at 120 degrees C, is used for chromogen formation, resulting in an absorption maximum at 290 nm. A progress diagram of the fermentation obtained by this technique is compared with one obtained by a microbiological agar diffusion method. The bioautographic evaluation of the active spots in the chromatogram are also presented. By our TLC method, the group of the active primycin components in the fermentation broth and by-products formed during the fermentation can be well separated. The relative intensities of the different TLC spots provide some information on the formation of the active components.     

活性炭分离富集技术的应用新进展

对活性炭分离富集技术的应用新进展进行综述。重点评述了活性炭的结构和吸附机理,活性炭对有机物的分离和吸附,活性炭对金属离子的分离和富集,共引用文献３５篇。     

THE PHOTOLYSIS OF TRYPTOPHAN WITH 337.1 nm LASER RADIATION

Abstract— Aqueous solutions of L-tryptophan were photolyzed by exposure to 337.1 nm radiation from a pulsed nitrogen laser. These data were compared with results for the 290 nm conventional-source photolysis of tryptophan. The progress of photolysis was monitored by fluorescence analysis of tryptophan. UV absorption spectroscopy, HPLC, TLC, and proton NMR spectroscopy. The loss of Trp was observed to be first order for 290 nm photolysis but of mixed order for 337.1 nm photolysis. Five photolysis products were detected by TLC analysis, including: N-formylkynurenine. kynurenine, tryptamine (detected after 290 nm photolysis but not 337.1 nm photolysis) and two unknown products. The tryptophan-containing peptides N-acetyl-tryptophanamide (NATA) and tryptophylglycine (Trp-Gly) were also observed to photolyze upon 337.1 nm laser radiation demonstrating that this phenomenon is not restricted to free tryptophan monomer.
Since Trp is not ordinarily thought to absorb U V radiation at wavelengths as long as 337.1 nm. a number of experiments were performed in an effort to determine the mechanism of photolysis at this wavelength. Evidence is presented which indicates that the 337.1 nm laser photolysis of Trp does not result from two photon absorption, dielectric breakdown, or other laser-specific processes. Instead. it is concluded that this photolysis results either from a very weak absorption tail extending to 337.1 nm in tryptophan itself or from a reaction involving an impurity sensitizer which absorbs the 337.1 nm radiation. The sensitizing impurity. if present, could not. however, be removed by preparative HPLC and could not be detected by TLC or fluorescence analysis.     

偏最小二乘法测定复方乙酰水杨酸片中的有效成分

将偏最小二乘法(PLS)与近红外漫反射光谱法相结合,对复方乙酰水杨酸片进行无损非破坏定量分析．建立了最佳的数学校正模型,比较了样品中3种有效成分(乙酰水杨酸、非那西丁和咖啡因)同时测定和单独测定时的主成分数对PLS定量预测能力的影响,预测了未知样品。3种有效成分同时测定和单独测定建立的PLS模型具有相同的主成分数,PLS预报浓度与参考浓度具有相近的标准偏差,说明用PLS法同时测定3种组分的含量是可行的。     

EFFECTS OF COUPLING AGENTS ON THE CRYSTALLIZATION BEHAVIOR OF PP/T-ZnOw COMPOSITES

The objectives of this paper are to understand the crystallization behavior of polypropylene(PP)composites with surface modified tetra-needle-shaped zinc oxide whisker(T-ZnOw).T-ZnOw was surface modified with different coupling agents,such as silane coupling agents(KH-550,KH-560)and titanate coupling agent(NDZ-105),in order to improve the compatibility between PP and T-ZnOw.DSC and POM were used to characterize the melt and crystallization behavior and the crystalline structures of the composites,respectively.The results show that the surface modified T-ZnOw acts as a nucleating agent of PP crystallization,depending on the coupling agent used for modification.KH-550 and KH-560 have more apparent role in improving the interfacial interaction than NDZ-105 and induce PP crystallization at higher temperature and with smaller spherulites size.The results also suggest that the crystallization behavior depends on not only the content of coupling agent,but also the content of the surface modified T-ZnOw used in the composites.