手性微柱高效液相色谱用于对映体的分离

报道了实验室自制的手性微柱高效液相色谱系统和纤维素类手性填料的制备方法, 以及用于对映体分离的应用研究. 研究了手性微柱的装填技术并考察了影响填料性能的关键因素. 优化了流动相的组成和流速对对映体拆分的影响. 成功地分离了5种对映体. 结果表明, 该系统操作简便、分离度高, 而且流动相消耗低, 分析速度快. 该系统可以用于实验室手性分离分析.     

咪唑键合硅胶固定相微柱液相色谱分离酚类和胺类化合物

由于微柱液相色谱(μ-LC)具有高检测灵敏度、低溶剂消耗、可以与质谱等多种检测器联用的优点,近年来受到广泛关注。将咪唑键合硅胶固定相填充到毛细管中,在自制的微柱液相色谱系统下利用此键合相具有的弱疏水作用,采用不同的流动相对酚类和胺类化合物进行了分离。结果表明,流动相中只需添加少量的有机溶剂就可以实现对一些有机化合物的分离,甚至可以只用纯水作流动相就能分离一些弱疏水性化合物,如酚类。微柱液相色谱的流动相用量少,避免或大大减少了对环境的污染。自制微柱液相色谱系统为下一步微柱液相色谱-质谱联用奠定了一定的基础。     

微柱高效液相色谱法测定葛根中的几种黄酮类成分

研究了用微柱高效液相色谱法测定葛根中的四种黄酮类成分。样品中的黄酮用甲醇超声振荡提取,然后用WatersXteraTMRP18(50×1.0mm,3.5μm)微柱吸附,以1%的乙酸溶液和甲醇为流动相梯度洗脱分离,用紫外二极管阵列检测器检测,结果满意。     

梯度加压毛细管电色谱同时分离大黄提取液中5种蒽醌类化合物

建立了同时分离药用大黄提取液中大黄酸、芦荟大黄素、大黄素、大黄酚和大黄素甲醚5种蒽醌类活性成分的梯度加压毛细管电色谱的新方法.实验结果显示,大黄提取液中的5种蒽醌化合物可在22min内完全分离,梯度洗脱微柱液相色谱的柱效为等度洗脱微柱液相色谱的6.63倍,梯度毛细管电色谱的柱效为梯度微柱液相色谱的4.6倍.     

微柱高效液相色谱和质谱法测定烟草样品中多酚

研究了用微柱高效液相色谱和质谱法测定烟草样品中植物多酚。烟草样品中植物多酚用80%的甲醇加热回流提取,提取液用Sep-Pak-C18固相萃取小柱预分离脱脂,以WatersXterraTMRP18(1.0mm×50mm,2.5μm)微柱为固定相,甲醇和1%的乙酸梯度洗脱为流动相分离;用紫外二极管矩阵检测器检测,并用质谱对未购到标样的绿原酸异构体进行了辅助定性。方法用于一些烟草样品中多酚的测定,回收率在97%-103%之间,RSD在1.4%-1.9%之间。     

胶束电动色谱法和微柱液相色谱法分析白藜芦醇的比较

白藜芦醇可以顺式和反式两种形式存在。它是一种具有药理活性的植物抗毒素,具有抗肿瘤、保护心血管、防止机体老化的功效。分别采用胶束电动色谱和微柱液相色谱两种方法对白藜芦醇的两种异构体进行了分离,并对这两种方法进行了比较。结果表明,两种方法均具有分离快速、重现性好、溶剂消耗少的特点,都适用于白藜芦醇的分析。     

微柱高效液相色谱法测定金银花中的多酚类物质

研究了用微柱高效液相色谱法测定金银花中的几种多酚类物质 (氯原酸、木犀草黄素、木犀草黄素 7 葡萄糖甙、木犀草黄素 7 半乳糖甙、槲皮素及槲皮素 3 葡萄糖甙)的方法。金银花样品中的多酚类物质用甲醇加热回流提取,然后以WatersXterraTMRP18 (1. 0mm×50mm, 2. 5mm)微柱为固定相, 1%的醋酸和甲醇梯度洗脱为流动相分离,在该色谱条件下,金银花中 6种多酚类成分在 4min内可达到基线分离;用紫外二极管矩阵检测器检测。方法标准回收率为 97% ~104%;相对标准偏差为 1. 6% ~2. 3%。测定了几种金银花样品中的多酚类物质,结果满意。     

微柱高效液相色谱与火焰光度检测器联用研究

报道了微柱高效液相色谱（micro-column HPLC）与火焰光度检测器（FPD）在线联用系统的研究,目的是发展一种不经复杂前处理步骤即可直接测定有机锡化合物的方法。三丁基锡氯化物（TBT）等经HPLC微柱分离后,通过毛细管连接引入特制的燃烧头,通过火焰光度检测器进行检测,对系统有关参数进行了优化和讨论。所建方法可以直接测定各种水样中的三丁基锡氯化物。     

咪唑键合硅胶液相色谱固定相的正相色谱行为

该文将咪唑键合硅胶液相色谱固定相填充到毛细管中,在自制的微柱液相色谱系统下以碱性(胺类)和酸性(酚类)化合物为溶质对该固定相的正相色谱行为进行考察.结果表明该键合相在正相色谱模式下对碱性化合物具有良好的分离选择性,而酸性化合物在流动相中加入改性剂乙酸的条件下也实现了较好的分离.研究表明,正相模式下该键合相的保留机理存在着氢键、静电吸引及π-π等相互作用机制.     

微柱液相色谱的研究进展

介绍了微柱液相色谱（μ-LC）。从理论上简单讨论了μ-LC的柱特性、色谱洗脱效应和柱外效应等一系列问题,综述了μ-LC的柱技术的最新进展,讨论了μ-LC对仪器和附件的要求,特别是微流量输液和检测技术,还探讨了μ-LC与多维色谱、质谱等技术的联用。     

Microcolumn liquid chromatography on carbon sorbents

Summary The retention volume dependences on the molar volume were found for aromatic compounds using liquid microcolumn chromatography. The contributions of the functional groups in molecules of these compounds to the total retention value were calculated from the capacity factor values. The comparison of capacity factor values for carbon sorbents and octadecyl-silicagel has shown that for several microcolumn separations the carbon sorbent column has a better selectivity and resolution than the octadecyl-silicagel column.     

Determination of serum metabolic profiles of bile acids by microcolumn liquid chromatography/laser-induced fluorescence

A method for the determination of individual free and conjugated bile acids in serum using microcolumn liquid chromatography coupled with a laser-induced fluorescence detector is described. Bile acids are separated into free/glycine-conjugate and taurine-conjugate fractions using a Sep-Pak SIL cartridge. The taurine-conjugated bile acid fraction is subjected to enzymatic hydrolysis. Subsequently, free and conjugated bile acids are labeled using 4-(bromomethyl)-7-methoxycoumarin as a fluorogenic reagent, producing stable derivatives that can be excited by the 325 nm line of a He/Cd laser. Prior to their fluorimetric detection, the individual components of a bile acid serum profile are separated by reversed-phase microcolumn liquid chromatography.     

Trace Analysis of Some Bivalent Cations using Peak Focusation Technique with Microcolumn Ion Chromatography

Abstract

Some conditions for cation focusation on cation resin when using the microcolumn liquid chromatograph with conductometric detection are derived and verified experimentally. Separation is carried out using a complexing agent and a competitive cation in the mobile phase. Cations of transition metals, alkaline earths and lead were analysed. Sensitivity of the method ranges within tenths of p.p.b.     

Micro-high-performance liquid chromatography platform for the depletion of high-abundance proteins and subsequent on-line concentration/capturing of medium and low-abundance proteins from serum. Application to profiling of protein expression in healthy and osteoarthritis sera by 2-D gel electrophoresis

In this investigation, an integrated microcolumn-based fluidic platform for the simultaneous depletion of high-abundance proteins and the subsequent on-line concentration/capturing of medium- and low-abundance proteins from human serum has been introduced. The platform consists of on-line coupling of tandem affinity micorcolumns to an RP microcolumn to achieve first the depletion of high-abundance proteins by the tandem affinity microcolumns followed by the concentration and capturing of medium- and low-abundance proteins by the RP microcolumn. The tandem affinity microcolumns are based on macroporous monoliths characterized by their relatively high permeability in pressure-driven flow while the RP microcolumn is packed with polymeric particles with an average particle diameter of 20 microm giving rise to a very little back pressure, thus allowing fast flow velocity across the coupled columns format and consequently short processing time of serum samples prior to analysis by 2-DE. The microcolumn-based fluidic platform was applied to serum samples from osteoarthritis (OA) donors before and after soy protein (SP) supplementation, and from healthy donors, and the resulting depleted serum samples from high-abundance proteins were profiled for protein expression by 2-DE. In general, the protein expression was lower in serum of the same OA patient after soy treatment than before soy treatment. Several proteins were down-regulated after soy treatment with transthyretin being the most affected by the SP supplementation. In addition, with respect to serum from healthy donors, the sera from OA patients showed difference in proteins expression.     

Indirect photometric detection of monovalent cations via postsuppressor ion replacement in microcolumn ion chromatography

Summary Monovalent cations were indirectly detected via postcolumn suppressor ion replacement in microcolumn ion chromatography. The ion-repalcement column loaded by chromophoric ions was connected to the suppressor column. The eluent, nitric acid, was converted to water through the suppressor and anion-replacement columns, while the analyte cations were coeluted with the chromophoric anions. The analyte cations were indirectly detected by measuring UV absorptions of the chromophoric anions.     

Axial temperature gradient and mobile phase gradient in microcolumn high-performance liquid chromatography

The effect of axial temperature gradient (ATG) along a microcolumn on the separation performance at both isocratic and gradient elution mode was investigated. A thermostat system was designed to form an ATG along the packed column. Polycyclic aromatic hydrocarbons (PAHs) were separated on a 0.53 mm  × 150 mm i.d. 5 μm C₁₈ microcolumn, with water and acetonitrile as mobile phase. The separation results obtained at mobile phase gradient (MPG) and ATG in microcolumn HPLC were compared with the results performed at ambient conditions. Extrapolated curves of peak width at half height (wh)versus lnk showed that wh is narrower at the same retention time when ATG was applied in addition to MPG. The column efficiency was enhanced 20-30% and the resolution was slightly reduced because of reduction of selectivity at elevated temperature at ATG condition. The RSD of retention time in ATG mode was less than 2.5%.     

Indirect conductimetric detection of nonelectrolytes in microcolumn liquid chromatography

Summary Indirect conductimetric detection of nonelectrolytes was investigated in microcolumn liquid chromatography. The mobile phase contained an electrolytic substance which maintained a high background and analytes were indirectly detected owing to a depression of the background signal. The dynamic reserve, defined as the ratio of the background to its noise level, was 9.3×10⁴, and the detection limits at S/N=3 were 10–32 ng for alcohols examined.     

Study of protein association and micelle formation in surfactants by microcolumn exclusion chromatography

The application of microcolumn exclusion chromatography to the determination of equilibrium and kinetic association constants for proteins is described. Taking phospholipase A₂ as an example, the relationship between association and enzymatic activity was investigated. A procedure for determination of the critical concentration of micelle formation (CCM) in surfactants was developed.