ISSN:0173-0835    

DOI:10.1002/elps.1150181202

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1997

数据来源: WILEY

摘要:

AbstractA review on peak broadening in capillary zone electrophoresis in free solutions is given which covers a selection of the literature published on this topic over the period mainly between 1992 and the beginning of 1997 (consisting of 71 publications). The contributions to peak dispersion from extracolumn effects (e.g.due to the finite length of the injection zone, or the aperture of the detector), from longitudinal diffusion, Joule heating, electromigration dispersion (concentration overload), a different path length of the solute ions, wall adsorption, laminar flow and the (longitudinally) homogeneous or nonhomogeneous electroosmotic flow are described. The latter may also occur when a longitudinally nonhomogeneous radial electric field is applied. Peak dispersion is depicted either by the plate‐height model, or the concentration of the solute as a function of space and time is calculated either analytically or numerically by solving the equation of continuity with appropriate initial and boundary conditions and possibly completed by equations governing further quantitie

ISSN:0173-0835    

DOI:10.1002/elps.1150181203

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1997

数据来源: WILEY

摘要:

AbstractCapillary isoelectric focusing (CIEF) provides excellent resolution of proteins with the advantage that separations are carried out in a capillary format with on‐tube detection and automated analysis. Recent advances in the technique provide improved resolution, reproducibility and reliability. This review summarizes improvements in sample preparation, capillary selection, and focusing and zone mobilization procedures which have helped CIEF become a more robust analytical method. New applications are reviewed, in particular the use of CIEF in analysis of biopharmaceutical product

ISSN:0173-0835    

DOI:10.1002/elps.1150181204

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1997

数据来源: WILEY

摘要:

AbstractThe use of isoelectric buffers in capillary zone electrophoresis is reviewed. Such buffers allow application of extremely high voltage gradients (up to 1000 V/cm in relatively high bore capillary,e.g.75 to 100 μm internal diameter), permitting separations of the order of a few minutes and thus favoring high resolution due to minimal, diffusion‐driven peak spreading. The fundamental properties of ampholytes are first discussed, such as buffering power (β) as a function of ΔpK. i.e.of the distance between the pIvalue and neighboring protolytic groups. The highest possible relative β value (= 2) is obtained for amphoteres possessing a ΔpK= 0.6, a condition not met by existing amphoteric species. A novel parameter for ampholyte evaluation is then proposed, namely the β/λ ratio,i.e.the ratio between the β power and conductivity at the pIvalue. It is additionally shown that the pIis not a constant value, but depends on ampholyte concentration in solution. In addition, at constant concentration, the theoretical pIcan change as a function of ΔpK. Isoelectric His and, to a lesser extent, Lys have been found to offer unique separations of oligonucleotides in sieving liquid polymers. In the absense of sieving media, isoelectric Asp, in presence of 7Murea (apparent pH 3.77), permits unique separations of oligonucleotides having the same length but different nucleotide composition. Isoelectric Asp (pI2.77 at 50 mMconcentration) provides a medium of high resolving power for generating peptide maps. In difficult cases, of coincident titration curves, the pH can be moved up to higher values (e.g.pH 3.0 for 30 mMAsp) thus eliciting separation of unresolved peptides at pH 2.77. This was illustrated by running peptide maps of tryptic digests of human β‐globin chains. Also imino diacetic acid (pI2.33 at 50 mMconcentration) allows generation of high resolution

ISSN:0173-0835    

DOI:10.1002/elps.1150181205

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1997

数据来源: WILEY

摘要:

AbstractCapillary isotachophoresis is a powerful electromigration separation method with a pronounced capability to concentrate trace components in diluted samples. At present, capillary isotachophoresis is utilized predominantly as the first step in on‐line combination with capillary zone electrophoresis. This article is a continuation of previous reviews and summarizes the results published during 1993–1

ISSN:0173-0835    

DOI:10.1002/elps.1150181206

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1997

数据来源: WILEY

摘要:

AbstractCapillary electrochromatography (CEC) is a hybrid between capillary electrophoresis and high performance liquid chromatography (HPLC) that has gained popularity in recent years. CEC uses an electrically driven flow to transport the solutes through the chromatographic column. Separation can be achieved by differential partition between two phases, differential electromigration, or a combination of these two. Herein, the main features of CEC are presented, including basic principles and a literature overview on different practical approaches used.

ISSN:0173-0835    

DOI:10.1002/elps.1150181207

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1997

数据来源: WILEY

摘要:

AbstractThe application of affinity capillary electrophoresis (ACE) to the study of molecular interactions is reviewed. ACE appears to be a sensitive, versatile and convenient tool to obtain reliable data on binding constants and stoichiometries of interacting systems using the Hummel‐Dreyer method and variants thereof. A powerful feature is the possibility to analyze simultaneously the affinity of a large number of compounds for the same ligand, making it a promising tool for the screening of large combinatorial librarie

ISSN:0173-0835    

DOI:10.1002/elps.1150181208

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1997

数据来源: WILEY

摘要:

AbstractThe purpose of this article is to review and evaluate the uses and potentials of capillary electrophoresis (CE) in immunoassay analysis (IA). This review will be divided into four sections. First, a brief summary of the fundamentals, applications and requirements of immunoassays in both research and clinical diagnostics will be given. This section will also cover the rationale behind the current research to combine CE and IA. Also, the specific needs to CE in this field will be addressed. Second, the modes of use of CE in IA will be discussed and typical applications for each will be given. Third, a separate section will be devoted to the investigation of performing immunoassays on micro fabricated devices, an interesting alternative to the conventional capillary‐based approach. Finally, a critical assessment of the current status and merits of this technology will be presente

ISSN:0173-0835    

DOI:10.1002/elps.1150181209

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1997

数据来源: WILEY

摘要:

AbstractCapillary electrophoresis (CE) has developed into a particularly effective means to determine apparent equilibrium constants for molecular association in solution (e.g., to micelles, cyclodextrins, antibiotics, proteins, RNA, DNA.etc.). The various experimental, graphical and mathematical approaches for determining association constants are reviewed. In CE, association constants can be calculated because there is a relationship between substrate concentration and the measured electrophoretic mobility of the solute. Most of the approaches for obtaining association constants by CE are conceptually and mathematically related to one another. Likewise, they are analogous to many spectroscopic techniques that are used for obtaining association constants. The advantages, limitations and proper use of the various CE approaches are examined.

ISSN:0173-0835    

DOI:10.1002/elps.1150181210

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1997

数据来源: WILEY

摘要:

AbstractIntegrated capillary electrophoresis (ICE) is emerging as a new analytical tool allowing fast, automated, miniaturized and multiplexed assays, thus meeting the needs of the pharmaceutical industry in drug development. The current state‐of‐the‐art of ICE is described with an emphasis on the choice of the support material (glass or polymeric materials), electrokinetic fluid handling, and injection and detection issues. Strategies and chip designs for pre‐ or post‐column derivatization, DNA sequencing, on‐line PCR analysis, on‐chip enzymatic sample digestion, fraction isolation, and immunoassays are presented. The review concludes with a

ISSN:0173-0835    

DOI:10.1002/elps.1150181211

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1997

数据来源: WILEY