非电荷型毛细管电色谱原位柱的色谱行为研究──阴离子表面活性剂的动态改性

 采用原位聚合的方法在毛细管中合成了非电荷型连续床电色谱原位柱 ,通过在电色谱流动相中加入阴离子表面活性剂十二烷基硫酸钠 (SDS)进行动态改性使其产生电渗流 ,考察了SDS浓度及有机改性剂浓度等因素对电渗流的影响。此类连续床柱制备容易 ,柱效可达 14万理论塔板 /m ,在不同的操作条件下有良好的稳定性 ,连续 10次运行 ,其死时间t0 与保留时间的精密度分别为 0 .2 2 %和 <0 .5 6 %。     

丙二酰胺型大环多胺键合固定相在毛细管开管电色谱中的应用

毛细管电色谱 ( Capillary electrochromatography,简称 CEC)是近年发展起来的一种高效、快速的新型微柱分离方法 [1～ 4] .由于它在毛细管柱内填充液相色谱固定相或者在毛细管内壁键合固定相 ,且采用电渗流作为驱动力 ,因而兼有高效液相色谱和毛细管电泳的分离特点 ,已应用于复杂的药物分析 [2 ] .填充柱毛细管柱具有工艺要求高、容易产生气泡、焦耳热和价格昂贵等缺点 .开管柱电色谱( Open- tubular CEC,简称 OTCEC)是将固定相键合或涂覆在毛细管的内壁 ,避免了上述缺陷 .因此已引起高度重视 [3,4] .大环多胺的结构与冠醚类似 ,是一…     

微电渗流毛细管原位柱中流动相组成对电渗流的影响

采用原位聚合的方法合成了一种新型微电渗流毛细管电泳原位柱。考察了不同有机调节剂种类和浓度 ,pH对电渗流的影响 ,在 pH值 2 .3～ 9.8范围内 ,电渗流小于 19.6× 10 -10 m2 V-1s-1。当有机调节剂浓度从 6 0 %增加到 90 %时 ,电渗流仅从 6 .6× 10 -10 m2 V-1s-1增大到 4 8.9× 10 -10 m2 V-1s-1。结果表明 ,此类微电渗流柱在电色谱分离模式下电渗流保持在较低水平     

毛细管电色谱研究的一些新进展

毛细管电色谱(Capillary electrochromatography,CEC)是一种新兴的以电渗流为驱动力的微柱分离分析新技术和新方法^[1].它主要依靠电渗流驱动流动相,流动相的流型为塞状平推流,具有与毛细管电泳(Capillary electrophoresis,CE)类似的高效性.     

新型反相毛细管硅胶电色谱整体柱的制备

色谱柱是色谱分离的核心,其性能的不断改进对色谱技术的发展极其重要.毛细管电色谱既作为固定相承担分离任务,又产生电渗流,作为驱动力带动溶质的迁移.     

毛细管电色谱柱内径对电渗流与电压关系的影响

考察不同内径的毛细管电色谱柱中分离电压对电渗流的影响，在不同内径的毛细管电色谱柱中，电渗流与电压都呈较好的线性关系，与毛细管电色谱柱的内径无关，由于焦耳热的影响，在电压变化幅度较大的情况下，电渗流与电压的关系曲线呈线性弯曲，在大内径毛细管电色谱柱上更加明显。     

毛细管电色谱分析苯氧羧酸类药残的研究

毛细管电色谱(CEC)是近年发展起来的一种高效、快速微柱分离方法,主要分为填充毛细管电色谱,开管毛细管电色谱和整体式毛细管电色谱.开管毛细管电色谱无柱塞和填料,不易产生气泡,且无涡流扩散,能获得较高柱效,其电渗流流速比填充柱大60%,适用于快速分析,具有良好的应用前景.     

蛋白A连续床亲和毛细管色谱柱的制备及性能考察

人免疫球蛋白 G(HIg G)是一种重要的生物大分子 ,是人血浆中的主要成分之一 ,通常采用免疫学的方法测定 .蛋白 A(Protein A)与免疫球蛋白 (HIg G)的 Fc区之间具有很强的特异性亲和作用 ,因而固载蛋白 A的亲和介质可用于免疫球蛋白及单克隆抗体的分离、纯化和分析测定[1～ 3 ] .根据固定相存在形式的不同 ,毛细管色谱柱主要有开管、填充和连续床柱 3种方式 .连续床具有相比高、易制备 (一步合成 )、孔径易控制、不需烧塞子和易改性等优点 .连续床与其它常用的亲和介质 (如球型凝胶颗粒、灌流色谱基质 [4、 5] 、膜介质 [6,7] 等 )相比具…     

连续二维开管离子交换/反相整体柱毛细管电色谱的构建与评价

在毛细管中原位合成反相整体色谱柱,并在同一根毛细管柱中的其余部分通过在内表面涂覆N-[3-(三甲氧基硅烷)-丙基)]-乙二胺(PEDA)使其具有离子交换功能,制备成连续二维开管离子交换/反相整体柱毛细管电色谱柱.通过对7种有机酸的分离探讨了开管柱中离子交换对分离的影响,进一步以天麻提取物为样品,对二维分离系统加以评价,...     

电色谱整体柱的研究进展*

电色谱整体柱是通过原位聚合或固化于柱管内部的方法来制备的一种新型色谱柱.与常规的填充毛细管柱不同的是,其制备方法具有简易性和易于实现色谱填料表面化学性质多样性的特点,已迅速成为优异的毛细管电色谱固定相形式.本文综述了毛细管电色谱整体柱研究的最新进展.     

Cetyltrimethylammonium bromide- and ethylene glycol-assisted preparation of mono-dispersed indium oxide nanoparticles using hydrothermal method

The influence of cetyltrimethylammonium bromide and ethylene glycol on the size and dispersion of indium oxide nanoparticles prepared under hydrothermal conditions was investigated. The precursor compound, indium hydroxide, obtained by the hydrothermal method in the absence as well as the presence of cetyltrimethylammonium bromide, was converted to indium oxide by sintering at 400°C. The formation of nanoscale indium oxide upon sintering was ascertained by the characteristic infrared adsorption bands and X-ray diffraction patterns of indium oxide. Transmission electron microscopy and band gap values confirmed that the cetyltrimethylammonium bromide facilitated the formation of indium oxide nanoparticles smaller in size and narrower in distribution than those prepared without the assistance of cetyltrimethylammonium bromide.     

模板剂对全硅MCM-41介孔分子筛结构的影响

分别采用十六烷基三甲基溴化铵和十六烷基三乙基溴化铵作为模板剂,硅溶胶为硅源,用水热晶化法在碱性（NaOH）介质中合成了MCM-41介孔分子筛样品.通过XRD、N2吸附-脱附、TG-DTA、IR等测试手段对这两种样品进行了对比表征分析.考察了两种不同模板剂对其晶体结构、比表面及孔径大小的影响.实验结果表明,相对于十六烷基三甲基溴化铵做模板剂,采用大头基的十六烷基三乙基溴化铵可以合成较大孔径和孔容（分别为4.72 nm和1.14 cm3•g-1）的MCM-41介孔分子筛,而且具有较窄的孔径分布,因此对于合成大孔径的介孔分子筛MCM-41,十六烷基三乙基溴化铵是一种很好的模板剂.     

Separation of aromatic sulfonate compounds by coelectroosmotic micellar electrokinetic chromatography

Summary Coelectroosmotic micellar electrokinetic chromatography (coelectroosmotic MEKC) has been investigated for the separation of twelve aromatic sulfonate compounds. The advantage of this method is that it combines the efficient separation characteristic of MEKC and the short analysis time of the coelectroosmotic mode. MEKC was performed with either cetyltrimethylammonium bromide (CTAB) or polyethylene glycol dodecyl ether (Brij 35) surfactants as pseudostationary phases and 2-propanol as organic modifier. The electroosmotic Flow (EOF) was reversed by adding two types of EOF modifier, an alkylammonium salt (cetyltrimethylammonium bromide, CTAB) or a cationic polyelectrolyte (hexadimetrine bromide, HDB). The surfactant concentration, applied voltage, and temperature were optimized, the influence of 2-propanol on the MEKC resolution of the compounds was studied. The effect of the osmotic modifier on the separation was also investigated.     

Adsorption of Cationic Surfactants on Highly Dispersed Silica

Comparative study was made of adsorption of cationic surfactants, decamethoxine, ethonium, and cetyltrimethylammonium bromide, on a highly dispersed amorphous silica at different pH values. Contrary to the adsorption of monoquaternary ammonium compound, cetyltrimethylammonium bromide, the adsorption of bis(quaternary ammonium) compounds, ethonium and decamethoxine, was found to be caused mainly by electrostatic interaction. The adsorption of antiseptic decamethoxine is reversible at pH 6; this may be used to design carriers capable of controlled drug release into the surrounding medium.     

Investigation of the surfactant type and concentration effect on the retention factors of glutathione and its analogues by micellar electrokinetic chromatography

In the present study, a micellar electrokinetic chromatographic method was used to determine the retention factors of hydrophilic monomeric and homodimeric forms of glutathione analogues. Ionic‐liquid‐based surfactant, 1‐tetradecyl‐3‐methylimidazolium chloride, as well as cetyltrimethylammonium bromide and phosphate buffer (pH 7.4) were employed in the experiments. Since the studied peptides possess a negative charge under physiological conditions, it is expected that the peptides interact with the oppositely charged 1‐tetradecyl‐3‐methylimidazolium chloride and cetyltrimethylammonium bromide micelles via hydrophobically assisted electrostatic forces. The dependence of the retention factor on the micellar concentration of 1‐tetradecyl‐3‐methylimidazolium chloride and cetyltrimethylammonium bromide is nonlinear and the obtained curves converge to a limiting value. The retention factor values of GSH analogues were in the range of 0.36–2.22 for glutathione analogues and –1.21 to 0.37 for glutathione when 1‐tetradecyl‐3‐methylimidazolium chloride was used. When cetyltrimethylammonium bromide was employed, the retention factor values were in the range of 0.27–2.17 for glutathione analogues and –1.22 to 0.06 for glutathione. If sodium dodecyl sulfate was used, the retention factor values of glutathione analogues with carnosine moiety were in the range of –1.54 to 0.38.     

Sensitive microdetermination of scandium,yttrium, and lanthanides using Eriochrome azurol B in the presence of a micelle-forming cationic surfactant

The chelation reactions of Sc³⁺, Y³⁺, and some lanthanides with Eriochrome azurol B in the presence and absence of cetyltrimethylammonium bromide has been studied in detail. The complexes show a marked bathochromic shift in their λ_max at pH 6.0. The composition of the complexes in the absence and presence of cetyltrimethylammonium bromide was found to be 1:2 (Metal:ligand). The values of the conditional formation constants have also been evaluated. The studies were further extended to the analytical aspects of the complex equilibria and a suitable procedure has been recommended for the spectrophotometric microdetermiantion of Sc³⁺, Y³⁺, and some lanthanides under study using Eriochrome azurol B in the presence of cetyltrimethylammonium bromide which considerably increases the sensitivity of the color reaction. The use of Eriochrome azurol B in the presence of cetyltrimethylammonium bromide as a complexometric indicator has also been reported.The effect of surfactant concentration and the effect of mineral salts on the absorption spectra of Eriochrome azurol B at pH 11.6 and 6.0 have also been reported.     

Hyaluronan-assisted synthesis of silver nanoparticles and nanowires

Research on Chemical Intermediates - Silver nanowires (NWs) were successfully synthesized in high yield in cationic surfactant solutions of cetyltrimethylammonium bromide (CTAB) with hyaluronan...     

Synthesis of single-crystalline nanobelts of ternary bismuth oxide bromide with different compositions

Ternary bismuth oxide bromide nanobelts have been prepared by using the cationic surfactant cetyltrimethylammonium bromide (CTAB) as the bromine source; their composition can be easily controlled by changing the reaction conditions.     

Application of Central Composite Design for the Determination of Exfoliating Agents in Cosmetics by Capillary Electrophoresis with Electroosmotic Flow Modulation

Multivariate analysis within central composite design is applied to simplify an optimization procedure and explore the interactions among experimental parameters in analytical chemistry. In this study, central composite design was used to identify the optimal capillary electrophoresis conditions with electroosmotic flow modulation to determine seven exfoliating agents in cosmetics. The influence of phosphate concentration, cetyltrimethylammonium bromide concentration, and methanol percentage on the response was evaluated by the use of the chromatographic exponential function to simultaneously investigate the resolution and separation under sixteen sets of capillary electrophoresis conditions. The optimized conditions were 150 mM phosphate solution (pH = 7) containing 0.5 mM cetyltrimethylammonium bromide, 3 mM γ-cyclodextrin, and 25% methanol as the running buffer. To shorten the analysis time, an electroosmotic flow modulating agent (cetyltrimethylammonium bromide) was added to the separation buffer. Calibration plots were linear (r ≧ 0.998) with high precision and accuracy in the homemade cosmetic matrix. The exfoliating agents in two commercial cosmetic products were determined using the optimized conditions, and the results correlated well with results obtained by high-performance liquid chromatography–mass spectrometry.     

1-(5-萘酚-7-磺酸)-3-[4-(苯基偶氮)苯基]-三氮烯的合成及与阳离子表面活性剂的显色反应

报道了1-（5-萘酚-7-磺酸）-3-[4-（苯基偶氮）苯基]-三氮烯（NASAPAPT）的合成，研究了该试剂与阳离子表面活性剂溴化十二烷基二甲基苄铵（DDMBAB），溴化十六烷基三甲铵（CTMAB）、溴化十六烷基吡啶（CPB）、溴化十四烷基吡啶（TPB）显色反应的条件。测定了显色反应的灵敏度，符合比尔定律的范围。建立了光度法测定微量阳离子表面活性剂的新方法。