双子表面活性剂及其保护的纳米金作为缓冲添加剂用于毛细管电泳蛋白质分离

报道了使用阳离子双子表面活性剂作为毛细管电泳的缓冲添加剂用于同时分离酸性和碱性蛋白质.在酸性的缓冲条件下,只需要使用低浓度的阳离子双子表面活性剂（0.1mmol/L18-s-18）作为缓冲液的添加剂,就可以有效地抑制酸性和碱性蛋白质在毛细管壁的吸附,从而得到高效的蛋白质分离.实验表明,较小的胶束尺寸（如s=5～8）比大的胶束尺寸（如s〈4或〉10）能更有效地抑制酸性蛋白质的吸附.改变双子表面活性剂的中间基的长度能够对蛋白质的电泳淌度进行一定的调节,从而对分离的选择性进行一定的优化.在最优的实验条件下,蛋白质迁移时间的日内和日间标准偏差（RSD）分别小于0.8%和2.2%,回收率为79%到100.4%.另外,还考察了双子表面活性剂保护的金纳米颗粒用作毛细管电泳缓冲添加剂在蛋白质分离中的应用.实验表明,在缓冲液中加入纳米金能够缩短分析时间,并能小幅度地提高分离效率.最后,使用该方法分析了一系列复杂生物样品,包括血浆、红细胞和鸡蛋清样品,均得到了满意的结果.     

Improvement in protein separation in Barretts esophagus samples using two-dimensional capillary electrophoresis analysis in presence of cyclodextrins as buffer additives

In two-dimensional capillary electrophoresis (2DCE) components are separated based on their size and hydrophobicity. A preliminary run separates analytes in the first capillary based on size (CSE). Following that, fractions are electrokinetically transferred across an interface into a second capillary, where components are further resolved according to hydrophobicity. In order to succeed in this analysis, two orthogonal methods should be selected for the different modes. The transfers from the first to the second capillary must be efficient in order to reduce tailing effects and lost of resolution. We report a new method to improve the resolution with our 2DCE instrumentation using CD doped buffers. When methyl beta cyclodextrin (mβCD) is added to the 2DCE interface buffer a stacking effect is described in the transfers from the first to the second dimension. In addition to that, changes in retention times are observed when proteins form complex with CD's helping in the separation. Protein fingerprints were obtained from BE homogenates using this method in presence of methyl beta cyclodextrin (mβCD). Within-day and between-day precision has been studied in order to establish the reproducibility of the methodology proposed.     

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.     

Rapid separation of basic drugs by nonaqueous capillary electrophoresis

Summary Nonaqueous capillary electrophoresis (NACE) has been used to achieve rapid separations of basic drugs. A high electric field was obtained by using short capillaries. Baseline separations of basic drugs, including amphetamines, tropane alkaloids and local anesthetics, were achieved in 1 min by selection of the appropriate organic solvent and electrolyte composition. Thus, high-throughput analyses can be performed. Peak efficiency up to 9154 theoretical plates s⁻¹ was achieved in a separation performed at 923V cm⁻¹. No discernible loss in resolution was observed when a conventional capillary (64.5cm) was replaced by a short (32.5 cm) capillary.     

Separation of basic proteins and peptides by capillary electrophoresis using a cationic surfactant

Incorporation of a low concentration of cetyltrimethylammonium bromide (CTAB) in the running electrolyte is shown to dynamically coat the silica capillary and to reverse the direction of electroosmotic flow. The CTAB coating prevented interaction of proteins with the capillary surface and enabled sharp peaks to be obtained in the electropherograms. A systematic study of experimental parameters demonstrated the importance of selecting a suitable buffer electrolyte and an appropriate pH. Excellent separations were obtained for five proteins, three enkephalins, and six dipeptides with an efficiency of approximately 500,000 theoretical plates per meter. The method developed is very simple to perform and was found to give excellent reproducibility.     

金纳米修饰毛细管电泳分离氨基苯甲酸

报道了一种金纳米修饰毛细管电泳分离、测定氨基苯甲酸的新方法。采用制备的金纳米进行了石英毛细管修饰。探讨了修饰金纳米浓度、修饰时间以及缓冲溶液加入一定浓度的金纳米对三种氨基苯甲酸分离和测定的影响,优化了分离电压、酸度以及缓冲溶液浓度等实验条件。结果表明金纳米的存在,显著的改进了氨基苯甲酸分离的选择性,增强了分离效率。在优化的实验条件下,进行了邻、间、对三种氨基苯甲酸的分离和测定。线性浓度范围为0.5–40 µg·mL,相关系数0.9978-0.9992。检测限(S/N = 3) 为0.1-0.5µg·mL。     

Separation of open-cage fullerenes using nonaqueous capillary electrophoresis

In this study, nonaqueous capillary electrophoresis (NACE) was used to separate three open-cage fullerenes. Trifluoroacetic acid (TFA) was used as the nonaqueous background electrolyte to change the analytes’ mobilities. The selectivity and separation efficiency were critically affected by the nature of the buffer system, the choice of organic solvent, and the concentrations of TFA and sodium acetate (NaOAc) in the background electrolyte. The optimized separation occurred using 200 mM TFA/20 mM NaOAc in MeOH/acetonitrile (10:90, v/v), providing highly efficient baseline separation of the open-cage fullerenes within 5 min. The migration time repeatability for the three analytes was less than 1% (relative standard deviation). Thus, NACE is a rapid, useful alternative to high-performance liquid chromatography for the separation of open-cage fullerenes.     

The effect of sample salt additives on capillary electrophoresis analysis of intact proteins using surface modified capillaries

The effect of adding alkali salts to protein samples for capillary electrophoretic (CE) analysis of intact proteins was studied. A high degree of peak stacking, even for large proteins, was found to occur when alkali salts were added to the sample. The addition of salt to the protein sample promotes a strong improvement in the peak efficiency of individual proteins giving up to 2.1 × 10⁶ apparent plates/m. The concentration of salt required in the sample to reach optimal peak efficiency show dependency on both the molecular weight and molar concentration of the protein. However, adding salt will, at a sufficiently high concentration, cause a mixture of proteins to co-migrate to one very sharp peak. The observed sample stacking effect was obtained with a number of different surface modified silica capillaries indicating a general phenomenon and not surface coating specific.     

Separation of fluoroquinolones in acidic buffer by capillary electrophoresis with contactless conductivity detection

A method to determine five fluoroquinolones (FQs), namely, rufloxacin (RUF), ciprofloxacin (CIP), enrofloxacin (ENO), gatifloxacin (GAT) and moxifloxacin (MOX), in acidic buffer by capillary electrophoresis (CE)-capacitively coupled contactless conductivity detection (C⁴D) technique is presented. Separation was carried out in a fused-silica capillary (42 cm × 50 μm) using a buffer composed of 10 mM tartaric acid, 14 mM sodium acetate and 15% (v/v) methanol at pH 3.8. The RSDs of the migration times and peak areas were 0.65% and 12.3% (intraday), 1.28% and 8.8% (interday), respectively. CE-C⁴D in combination with liquid–liquid extraction (LLE) as clean-up and preconcentration procedure, allows detection of the FQs in fortified chicken muscle samples with detection limits of 6.8–11.7 ng/g. This method shows potential in rapid determination of FQs in samples with complex matrix.     

毛细管电泳技术在重大疾病特异性蛋白质分析中的应用

人类重大疾病特异性蛋白质的识别、鉴定等是目前生命科学亟待解决的问题。毛细管电泳技术用于蛋白质分析,具有装置简单、分析速度快、试剂和样品消耗少以及有多种分离模式和检测手段等特点。本文综述了毛细管电泳技术在人类重大疾病特异性蛋白质分析中的应用,包括肿瘤疾病、神经退行性疾病和输血性传染病等的特异性蛋白质检测。     

Separation of anilines by capillary electrophoresis with small ionic compounds as buffer additives

Addition of either ethanesulfonic acid or protonated triethylamine to the background electrolyte was found to markedly improve the separation of protonated anilines by capillary electrophoresis. These additives appear to form a thin coating on the capillary surface via a dynamic equilibrium. This results in a change in electroosmotic flow and reduces interactions of the sample cations with the silica surface. A mixture of 10 substituted anilines could be separated, including several positional isomers. Migration times of the sample cations were reproducible with a RSD less than 1.0%.     

高效毛细管电泳分离测定水中的乙酸和氯代乙酸

用邻苯二甲酸氢钾(pH=5.4)缓冲液作为电泳的背景电解质,以十六烷基三甲基溴化铵作为电渗流抑制剂,用甲基叔丁基醚作为萃取剂处理水样,建立了一种测定水中的乙酸和氯代乙酸的简单灵敏的毛细管区带电泳(紫外检测)法.测定结果表明,分析物的迁移时间和峰面积的日内相对标准偏差分别低于0.33%和4.45%,日间相对标准偏差分别低...     

Investigation of the synergistic effect with chiral D-penicillamine functionalized gold nanoparticle as an additive for enantiomeric separation in capillary electrophoresis

The authors describe a synergistic system for nanoparticle based chiral separation. It is based on the use of a conventional chiral selector hydroxyproyl-β-cyclodextrin and a kind of gold nanoparticle functionalized with D-penicillamine as an additive. This nanomaterial displays a synergistic effect on the efficiency of the enantioseparation of the chiral drugs amlodipine, tropicamide, and ofloxacin. A comparative study on the enantioseparation capability of three separation systems, viz. (a) single hydroxyproyl-β-cyclodextrin system, (b) achiral citrate capped gold nanoparticle/ hydroxyproyl-β-cyclodextrin system, and (c) chiral D-penicillamine functionalized gold nanoparticle/ hydroxyproyl-β-cyclodextrin system was performed. The results show that the D-penicillamine functionalized gold nanoparticle/hydroxyproyl-β-cyclodextrin synergistic system has remarkable superiority. The effects of concentrations of D-penicillamine functionalized gold nanoparticle and hydroxyproyl-β-cyclodextrin, of buffer pH value and concentration, and of applied voltage on the performance of enantioseparation were investigated.     

Separation and analysis of triazine herbcide residues by capillary electrophoresis

Triazines are widely used in agriculture around the world as selective pre‐ and post‐emergence herbicides for the control of broad leaf and grassy weeds. With high toxicity and persistence, triazines can contaminate the environment and crops, so the development of rapid and sensitive methods for the determination of different triazines is necessary. Capillary electrophoresis comprises a group of techniques used to separate chemical mixtures. Analytical separation is based on different electrophoretic mobilities. This review focuses on the analysis of triazine herbicides with different modes of capillary electrophoresis, including capillary zone electrophoresis, micellar electrokinetic capillary electrophoresis, capillary electrochromatography and nonaqueous capillary electrophoresis. Determinations of triazines in various matrices such as surface water, groundwater, vegetables, soil and grains are emphasized. Copyright © 2014 John Wiley & Sons, Ltd.     

Use of zwitterionic buffer additives to improve the separation of proteins in capillary zone electrophoresis

In CZE, the adsorption of the proteins on the capillary wall is a common problem. This paper describes the simple method of utilizing zwitterionic buffer additives to improve the separation of proteins in untreated fused silica capillaries at neutral pH. Three kinds of zwitterion are evaluated in the separation of acidic, neutral, and basic proteins, including their effect on protein efficiency, mobility, separation, and resolution; the difference between the effects of the different additives are also highlighted. The method has proved to be a possible means of reducing protein adsorption, especially for basic proteins.     

Cloud point extraction as a sample enrichment technique for capillary electrophoresis–An overview

Abstract

Cloud point extraction (CPE) is a simple, inexpensive and green sample enrichment technique for different analytes in different matrices. In this technique surfactant solution is used at concentration above critical micelle concentration to extract the analytes from various matrices. Capillary electrophoresis (CE) and family of related techniques have emerged as powerful analytical techniques for pharmaceutical, biomedical, food and environmental analysis. In this review we have described the applications of CPE coupling with CE.     

Analysis of neutral surfactants by non-aqueous capillary electrophoresis using an electroosmotic flow reversal

The separation of KM 20, that is in fact a mixture of non-ionic surfactants, was carried out by non-aqueous capillary electrophoresis. This complex mixture resulting from the condensation of ethylene oxide with fatty alcohols does not have chromophoric moieties. So, we analysed it after derivatization by means of 3,5-dinitrobenzoyl chloride. The proposed approach is based both on the formation of complexes with alkaline or ammonium cations in methanol and on the utilisation of a positively charged capillary. From a comparative study on the capillary treatment procedure, we used hexadimethrine bromide as electroosmotic flow reverser in order to obtain both repeatable analyses and good resolutions of the largest KM 20 oligomers. Then, among the five cations used to form complexes with KM 20, we pointed out that ammonium cation led to the best resolutions. Moreover, we evidenced that the counter-ion of this cation had a great influence on resolution because it modified the magnitude of electroosmotic flow. Ion pair formation that is more or less strong between ammonium and its counter-ion was involved in this variation of electroosmotic flow. So, we calculated the association constants for various ammonium salts in methanol. Then, using ammonium chloride as background electrolyte, we optimised the concentration of this salt, in methanol, in order to reach the optimal separation of KM 20 oligomers. Thus, a baseline separation was obtained by using 6 x 10(-2) mol/L NH4Cl as running electrolyte. In these conditions, we separated, in about 30 min, more than 30 oligomers of KM 20. The distribution of these oligomers that was determined from the optimal separation, appeared consistent with that obtained from HPLC analyses. Indeed, we determined that the mean ethoxylation number was equal to 18 while its real value is equal to 20.     

Capillary zone electrophoretic separation of basic proteins and drugs using guaran as a buffer modifier

Summary Guaran, a neutral polysaccharide, has been used as a buffer modifier to improve the separation of basic proteins and drugs. Migration reproductibility, peak shape and efficiency were improved when 0.1% guaran was added to the buffer. The concentration of guaran, ionic strength, and pH of buffer solution were optimized to obtain the optimum separation of proteins. Possible separation efficiencies of 700,000 plates per meter were obtained for test proteins. The relative standard deviation (% RSD) of the migration time of all test proteins was less than 0.5%. Improved separation of β-blockers was also observed when guaran was added to the buffer.     

Separation of ofloxacin enantiomers by capillary electrophoresis with fluorescence detection using deoxyribonucleic acid oligonucleotides as chiral selectors

This study used capillary electrophoresis with fluorescence detection- and a partial-filling mode-based method for chiral separation of ofloxacin. The deoxyribonucleic acid oligonucleotides with different base sequences were studied as potential chiral selectors including deoxyribonucleic acid tetrahedron, G-quadruplex, and G-riched double-strand deoxyribonucleic acid. Under the optimized conditions, all the deoxyribonucleic acid chiral selectors exhibited excellent chiral separation capabilities with a resolution higher than 1.5. The electrophoretic behavior of the ofloxacin enantiomer might result from the intermediate conjugate with different stabilities between chiral selectors and analytes by a combination of the hydrogen bond and spatial recognition structure. Moreover, satisfactory repeatability regarding run-to-run and interday repeatability was obtained, and all the relative standard deviation values of migration times and resolutions were below 4% (n = 6). Conclusively, both spatial structure and arrangement of the G bases potentiated the chiral separation capability of deoxyribonucleic acid for ofloxacin enantiomer. This work offered a stepping stone for enantioseparation using deoxyribonucleic acid as chiral selectors.