细胞电泳

历史 从1902年Lllie的发现算起,细胞电泳已有80多年的历史。其前60年的发展速度缓慢,研究局限在淌度测定及膜结构与功能间关系的探讨。对象包括红细胞,淋巴细胞、精子及微生物等易得样品。所用装置是1911年Ellis发明的细胞电泳计或其改进型。60年代后,在免疲学、临床医学、遗传工程等学科推动下,细胞电泳开始向广度和深度展开,同时涌现了多种新的、有效的电泳方法。1984年Hannig等发明连续流电泳,并首次分离到高纯的红细胞。接着他和Zeiller等用此分离淋巴细胞,发现T和B细胞具有不同的淌度,否定了淋巴细胞单一分布的旧结论,并得到其他研究结果的证实。他们还发展出广     

毛细管电泳在手性化合物分离分析中的研究进展

手性化合物的对映异构体往往表现出不同的生理活性,因此建立手性化合物的有效分离分析方法具有重要意义。毛细管电泳（CE）是一种分离效率高、分析速度快、样品用量少、分离模式灵活多样的分离分析方法,在手性化合物的分离和检测领域应用广泛。该文主要综述了2017~2019年CE在手性分离分析方面的最新进展,并对其未来的发展趋势进行了展望。     

对映异构体的高效毛细管电泳分离与测定

高效毛细管电泳是８０年代发展起来的一种高效、快速的新型分离技术，在对映异构体分离方面有着广泛的应用前景，本文介绍了这一新型分离技术用于对映体分离的基本原理，并列举了一些对映异构体分离的实例。     

毛细管电泳中的电渗及其控制

渗在毛细管电泳中与淌度生容量因子同等重要，它决定或控制电泳的分离模式、分离过程及其分离生现性等。本文对电渗的作用，控制方法进行了系统讨论，并介绍了此方面的研究进展及有关的问题。     

应用毛细管区带电泳分离分析蛋白质及多肽

生命科学研究的迅速发展对生物大分子的分离分析提出了更高的要求,促使人们不断研究和开发新型的高效、快速、选择性好的分离分析方法。传统的电泳技术是目前生物化学及分子生物学实验室中常用的分离分析和制备手段,但它周期长,操作繁     

无机阴离子的毛细管电泳分析

本文研究了常见无机阴离子的毛细管电泳规律，考察了分离电压、电解质熔液组成、浓度、ｐＨ值等对分离的影响，建立了高效、快速的无机阴离子毛细管电泳分析方法。在选定的实验条件下，各种常见无机阴离子在５ｍｉｎ内达到完全分离，对Ｂｒ＾－和Ｃｌ＾－的分离柱效每米可达７６万理论板数。迁移时间的相对标准偏差小于１％，峰面积的相对标准偏差小于５％，各离子的最低检测浓度为０．０５￣０．５μｇ／ｍｌ。     

寡糖的毛细管电泳分析

多种寡糖经α－萘胺衍生化后，用硼砂作为电泳介质，实现了高效毛细管电泳分离。比较了毛细管区带电泳和胶束毛细管电动色谱分离寡糖α－萘胺衍生物的电泳行为，对影响分离度的诸因素进行了考察，选择了最佳分离条件。     

环糊精及其衍生物在毛细管电泳中的应用

十一年前毛细管电泳(CE)出现时,在世界分析化学界引起了少有地关注和积极地效仿。十多年来各国科学家进行了大量的工作,使CE获得了迅速的发展。有人认为,目前CE最活跃的领域是柱工艺和毛细管柱表面化学以及选择性分离介质的研究。后者是为了分离一般情况下难以分离的各种异构体,尤其是对映异构体。在气相色谱(GC)和高效     

高效毛细管电泳分离中的化学平衡

在高效毛细管电泳（ＨＰＣＥ）中缓冲对分离有重要影响，缓冲中的化学平衡决定了待测组分的存在状态或形态，从而决定了组分的电泳尚度，淌度的差异是ＨＰＣＥ分离之基础，因此，溶液化学平衡在ＨＰＣＥ分离中起着重要作用，本文综述了电泳淌度，ＨＰＣＥ分离与化学平衡的关系，并要介绍了电泳淌度与酸碱平衡，络合平衡的关系，从化学平衡的角度，讨论了酸碱性化合物，金属离子，对映异构体等几大类化合物的ＨＰＣＥ分离。     

电泳技术在纳米颗粒分离中的应用

合成纳米颗粒常在尺寸和形状方面具有广泛分布.在很多实验中,需要利用一定大小及形状的纳米颗粒的独特物理化学性质,因此,简便快速的纳米颗粒分离技术越来越受到诸多科学领域的重视.电泳技术以其高分辨率,被广泛用于多种生物大分子如核酸、蛋白质等的分离纯化.纳米颗粒在尺寸上与生物体中的蛋白复合物、细胞器和微生物等十分接近,考虑到带电纳米颗粒与生物分子在电场中的运动行为的相似性,运用电泳技术进行纳米颗粒的鉴定、分离和纯化是一种新的思路,并取得了良好的实验结果.本文主要介绍了琼脂糖凝胶电泳、毛细管电泳以及其他一些电泳技术在纳米颗粒分离中的研究进展.     

Reduction in sample injection bias using pressure gradients generated on chip

Sample injection in microchip-based capillary zone electrophoresis (CZE) frequently rely on the use of electric fields which can introduce differences in the injected volume for the various analytes depending on their electrophoretic mobilities and molecular diffusivities. While such injection biases may be minimized by employing hydrodynamic flows during the injection process, this approach typically requires excellent dynamic control over the pressure gradients applied within a microfluidic network. The current article describes a microchip device that offers this needed control by generating pressure gradients on-chip via electrokinetic means to minimize the dead volume in the system. In order to realize the desired pressure-generation capability, an electric field was applied across two channel segments of different depths to produce a mismatch in the electroosmotic flow rate at their junction. The resulting pressure-driven flow was then utilized to introduce sample zones into a CZE channel with minimal injection bias. The reported injection strategy allowed the introduction of narrow sample plugs with spatial standard deviations down to about 45 μm. This injection technique was later integrated to a capillary zone electrophoresis process for analyzing amino acid samples yielding separation resolutions of about 4–6 for the analyte peaks in a 3 cm long analysis channel.     

Window optimization in isotachophoresis superimposed on capillary zone electrophoresis

A sample stacking procedure to which a specific combination of electrolyte solutions is applied is isotachophoresis (ITP) superimposed on capillary zone electrophoresis (CZE), a so-called ITP/CZE system. In ITP/CZE some components migrate in an ITP fashion on top of a background electrolyte, and the other analytes migrate in a zone electrophoretic manner. For such a system, the leading electrolyte consists of a mixture of an ionic species, L1, of high mobility (the leading ion of the ITP system), an ionic species, L2, of low mobility (the coions of the CZE system), and a buffering counter-ionic species, whereas the terminating solution only contains the ionic species L2 and the buffering counterions. The zones of the components migrating in the ITP/CZE mode are sharp owing to the self-correcting properties of the zones and the concentrations of the L1 ions of the system. Mobility windows can be calculated, indicating which ions can migrate in the ITP/CZE mode. In this article mobility windows are calculated by applying both strong and weak acids as L1 and L2 ions and it appears that mobility windows can be optimized by chosing different ratios of L1 and L2 as well as different pH values. It is possible to construct very narrow mobility windows, and thereby choose which component of a sample solution can be concentrated, and to what concentration, in a very selective way. The big advantage of ITP/CZE compared with applications such as transient ITP and transient stacking is that the stacked sample ionic species migrate in the ITP mode during the whole experiment; furthermore, they do not destack. Experimentally obtained electropherograms validate the calculated mobility windows for the ITP/CZE mode.     

Combining capillary electrophoresis with mass spectrometry for applications in proteomics

Mass spectrometry (MS)-based proteomics is currently dominated by the analysis of peptides originating either from digestion of proteins separated by two-dimensional gel electrophoresis (2-DE) or from global digestion; the simple peptide mixtures obtained from digestion of gel-separated proteins do not usually require further separation, while the complex peptide mixtures obtained by global digestion are most frequently separated by chromatographic techniques. Capillary electrophoresis (CE) provides alternatives to 2-DE for protein separation and alternatives to chromatography for peptide separation. This review attempts to elucidate how the most promising CE modes, capillary zone electrophoresis (CZE) and capillary isoelectric focusing (CIEF), might best be applied to MS-based proteomics. CE-MS interfacing, mass analyzer performance, column coating to minimize analyte adsorption, and sample stacking for CZE are considered prior to examining numerous applications. Finally, multidimensional systems that incorporate CE techniques are examined; CZE often finds use as a fast, final dimension before ionization for MS, while CIEF, being an equilibrium technique, is well-suited to being the first dimension in automated fractionation systems.     

Possibilities of column coupling electrophoresis provided with a fiber-based diode array detection in enantioselective analysis of drugs in pharmaceutical and clinical samples

The present work illustrated possibilities of column coupling electrophoresis combined with ionizable chiral selector and diode array detection (DAD) for the enantioselective analysis of trace drugs (pheniramine and its analogs) in pharmaceutical and clinical samples. Isotachophoresis (ITP), on-line coupled with capillary zone electrophoresis (CZE), served as an ideal injection technique (high sample load capacity, narrow and sharp drugs zones) of on-line pretreated samples (preseparation, purification and preconcentration of drugs) for the CZE stage. Enhanced (enantio)separation selectivity of CZE with ionizable chiral selector (carboxyethyl-beta-cyclodextrin recognized between drugs enantiomers on one hand as well as between drugs and sample matrix constituents on the other hand) enabled to obtain pure zones of the drugs enantiomers, suitable for their detection and quantitation. DAD in comparison with single wavelength UV detection enhanced value of analytical information verifying purity of drugs enantiomers zones (indicating interferents with different spectra to those of drugs). Obtained results indicated pure zones of interest confirming effective ITP-CZE (enantio)separation process. Distinguishing the trace analytes signals superposed on the baseline noise was provided with sufficient reliability (for this purpose the background correction and smoothing procedure had to be applied to the raw DAD spectra). The proposed ITP-CZE-DAD methods were characterized by favorable performance parameters (sensitivity, linearity, precision, recovery, accuracy, robustness, selectivity) and successfully applied for (i) enantiomeric purity testing of dexbrompheniramine in commercial pharmaceutical tablets and (ii) enantioselective metabolic study of pheniramine in human urine.     

Electromigration peak dispersion of isotachophoretic protein zones during capillary zone electrophoresis

The relationships between electromigration dispersion (EMD) and on-line isotachophoresis-capillary zone electrophoresis (ITP-CZE) are described for several basic model proteins and interleukin-6 (rhIL-6). During CZE separation of the highly concentrated analyte zones which were generated during the initial ITP step EMD evolves from intrinsic differences in conductivity between the focused ITP zones and the leading electrolyte. Nearly triangular peaks with a sharp front and diffuse rear side were observed. An electromigration dispersion factor (F_EMD) was introduced to measure peak asymmetry. EMD of individual peaks was shown to increase with the absolute amount of the respective analyte injected and with analyte mobility. Good linearity was observed when F_EMD was plotted against protein mobility (r > 0.95). The slope of the graphs describing this relationship increased with the amount of analyte injected. The influence of EMD on the separation efficiency of neighboring peaks appeared to be less pronounced than expected. Consecutive release from the ITP-stack during transition from ITP to CZE might be an explanation for this observation.     

Base-induced transient isotachophoretic stacking of acidic drugs in capillary zone electrophoresis

Online sample concentration of acidic drugs by transient isotachophoresis (t-ITP) with the injection of a base is described in capillary zone electrophoresis (CZE). A positively coated capillary was conditioned with background electrolyte (ammonium acetate at pH 6). A long plug of sample solution (S) prepared in ammonium acetate was then hydrodynamically injected followed by the base (tetrapropylammonium hydroxide). A negative voltage was applied and caused the hydroxide ions from the base to penetrate the S zone and created a pH junction that swept through the S zone. The analytes stack at the junction where the mechanism of focusing was transient ITP with the acetate and hydroxide ions as leading and terminating ions, respectively. The concentrated analytes separated in co-EOF CZE once the hydroxide was exhausted. The base stacking strategy was tested using hypolipidemic, nonsteroidal anti-inflammatory, and diuretic drugs, and afforded 19-37 improvements in peak height.     

Micelle to solvent stacking of organic cations in capillary zone electrophoresis with electrospray ionization mass spectrometry

The direction of the effective electrophoretic mobility of small organic cations in micellar electrokinetic chromatography using sodium dodecyl sulphate in a low-pH electrolyte can be reversed in the presence of organic solvent. This effective electrophoretic mobility change is presented here as a new dimension for on-line sample preconcentration of cations in capillary zone electrophoresis (CZE) using a background solution (BGS) modified by an organic solvent. The sample is prepared in a micellar solution without organic solvent. The focusing effect relies on the reversal in the effective electrophoretic mobility at the boundary zone between the micellar matrix and the BGS modified with organic solvent. This on-line sample preconcentration technique, called micelle to solvent stacking (MSS) afforded more than an order of magnitude improvement in concentration sensitivity compared to typical CZE-UV or CZE-electrospray ionization (ESI) MS analysis. The calculated limit of detection (S/N = 3) for pindolol and metoprolol analysed by MSS-CZE-ESI-MS was found to be 0.03 and 0.01 μg/mL, respectively.     

Multi-purpose capillary electrophoresis system with concentration gradient detection

A robust, inexpensive and versatile capillary electrophoresis (CE) system for routine and rapid analysis is reported, which consists of a rugged cartridge holding a 20-mum i.d. 15-cm long capillary, and an inexpensive, universal and sensitive concentration gradient detector. The design of the cartridge simplifies the sample introduction process and makes it possible to perform many separation modes, including moving boundary capillary electrophoresis (MBCE), capillary zone electrophoresis (CZE), capillary isotachophoresis (CITP) and capillary isoelectric focusing (CIEF), on the same system. This arrangement provides more information about a sample's components since analytes can be separated by different modes performed on the same CE system. The detector only consists of a low-power HeNe laser, or laser diode, and a photodiode position sensor. Amino acids and proteins of 10(-6)-10(-3)M concentration can be separated by different capillary electrophoretic modes, and detected directly by the detector. The universal detector shows particularly good sensitivity when applied to CE separation modes having self-concentration and focusing effects. Femtomoles of proteins were separated and detected with CIEF. In addition, a short and narrow capillary allows use of high electrical fields which facilitate rapid separations. Four amino acids at millimolar concentrations were fully separated and detected in less than 80 sec by the MBCE mode when a high electric field was applied. The physical size of the whole system is much smaller than that of conventional CE instruments with UV absorbance or fluorescence detector.     

Sample preparation for peptides and proteins in biological matrices prior to liquid chromatography and capillary zone electrophoresis

The determination of peptides and proteins in a biological matrix normally includes a sample-preparation step to obtain a sample that can be injected into a separation system in such a way that peptides and proteins of interest can be determined qualitatively and/or quantitatively. This can be a rather challenging, labourious and/or time-consuming process. The extract obtained after sample preparation is further separated using a compatible separation system. Liquid chromatography (LC) is the generally applied technique for this purpose, but capillary zone electrophoresis (CZE) is an alternative, providing fast, versatile and efficient separations. In this review, the recent developments in the combination of sample-preparation procedures with LC and CZE, for the determination of peptides and proteins, will be discussed. Emphasis will be on purification from and determination in complex biological matrices (plasma, cell lysates, etc.) of these compounds and little attention will be paid to the proteomics area. Additional focus will be put on sample-preparation conditions, which can be hard or soft, and on selectivity issues. Selectivity issues will be addressed in combination with the used separation technique and a comparison between LC and CZE will be made.     

Miniaturized two-dimensional capillary electrophoresis on a microchip for analysis of the tryptic digest of proteins

A two-dimensional capillary electrophoresis platform, combining isoelectric focusing (IEF) and capillary zone electrophoresis (CZE), was established on a microchip with the channel width and depth as 100 mum and 40 mum, respectively. With polyacrylamide as permanent coating, EOF in the microchannel, which could impair the separation, was decreased to 3.4x10(-9)m(2).V(-1).s(-1), about 1/10 of that obtained in the uncoated set-up. During the separation, peptides were first focused by IEF in the first dimensional channel, and then directly driven into the perpendicular channel by controlling the applied voltages, and separated by CZE. Effects of various experimental parameters, including the electric field strength, channel length, and injection frequency from the first to the second dimensional separation channel, were studied. Under optimized condition, the digests of BSA and proteins extracted from E. coli were separated, and a peak capacity of 540 was obtained, which was far greater than that obtained by each single dimensional separation. All these results showed the promise of multidimensional separation on a microchip for the high-throughput and high-resolution analysis of complex samples.