Electrophoresis separation science

The following texts provide a good introduction to the broad field of separations, including chromatography and electrophoresis. Giddings, J. C. Unified Separation Science. Wiley-Interscience New York, 1991. 

The natural world is one of eomplex mixtures petroleum may eontain 10 -10 eomponents, while it has been estimated that there are at least 150 000 different proteins in the human body. The separation methods necessary to cope with complexity of this kind are based on chromatography and electrophoresis, and it could be said that separation has been the science of the 20th century (1, 2). Indeed, separation science spans the century almost exactly. In the early 1900s, organic and natural product chemistry was dominated by synthesis and by structure determination by degradation, chemical reactions and elemental analysis distillation, liquid extraction, and especially crystallization were the separation methods available to organic chemists. 

The spectrum of new analytical techniques includes superior separation techniques and sophisticated detection methods. Most of the novel instruments are hyphenated, where the separation and detection elements are combined, allowing efficient use of materials sometimes available only in minute quantities. The hyphenated techniques also significantly increase the information content of the analysis. Recent developments in separation sciences are directed towards micro-analytical techniques, including capillary gas chromatography, microbore high performance liquid chromatography, and capillary electrophoresis. 

Bowser, M.T. and Chen, D.D.Y., Recent developments toward a unified theory for separation science (mini-review), Electrophoresis, 19, 1586, 1998. 

R. M. C. Sutton and A. M. Stalcup. Preparative Electrophoresis. Encyclopedia of Separation Science, Academic Press Ltd (1999) in press. 

Innovations in separation science continued on this theme and provided one of the most powerful separation techniques used in biochemistry, where proteins are separated with isoelectric focusing (IEF) applied in one direction, and gel electrophoresis (GE) applied at aright angle to the first separation direction (O Farrell, 1975 Celis and Bravo, 1984). In this case, proteins are first separated according to their isoelectric point, measured in p/units, and then according to their molecular weight by gel electrophoresis. The size separation step is usually aided by addition of a surfactant, most typically sodium dodecyl sulfate (SDS), and the gel material is a polyacrylamide formulation. 

This book is organized into five sections (1) Theory, (2) Columns, Instrumentation, and Methods, (3) Life Science Applications, (4) Multidimensional Separations Using Capillary Electrophoresis, and (5) Industrial Applications. The first section covers theoretical topics including a theory overview chapter (Chapter 2), which deals with peak capacity, resolution, sampling, peak overlap, and other issues that have evolved the present level of understanding of multidimensional separation science. Two issues, however, are presented in more detail, and these are the effects of correlation on peak capacity (Chapter 3) and the use of sophisticated Fourier analysis methods for component estimation (Chapter 4). Chapter 11 also discusses a new approach to evaluating correlation and peak capacity. 

One of the primary challenges facing the field of separation science is the analysis of the entire complement of proteins produced by an organism—a field of research known as proteomics. 2D gel electrophoresis remains the gold standard in protein separations, with the ability to resolve as many as 5000 proteins in a single gel... 

Fountoulakis, M., Two-dimensional electrophoresis, in Encyclopedia of separation science II/Eletrophoresis Academic Press, London, 2000, pp. 1356-1363. 

Discussions of electrophoretic data handling usually include mention of separation and resolution. Although the two terms are not synonymous, they are often treated as such. In the terminology of separation science, separation refers to the distance between two adjacent band centers. Because bands are seen as being sharply defined with clearly evident blank spaces between adjacent bands, for practical purposes, separation is often taken to be the distance between the top of the faster running of two adjacent bands and the bottom of the slower one. It is the distance between the top of the bottom band and the bottom of the top band. This definition seems preferable to the rigorous one in electrophoresis. 

Geiser, L., Henchoz, Y., Galland, A., Carrupt, P.A. and Veuthey, J.L. (2005) Determination of pKa values by capillary zone electrophoresis with a dynamic coating procedure. Journal of Separation Science, 28, 2374-2380. 

Sonlinova V, Kasicka V. Recent applications of conductivity detection in capillary and chip electrophoresis. Journal of Separation Science 29, 1743-1762, 2006. 

Danilo Corradini is research director at the Institute of Chemical Methodologies of the Italian National Research Council (CNR) and a member of the General Scientific Advisory Board of CNR. His involvement in separation science started in 1976 with his research work on chromatography and electrophoresis for his PhD studies in chemistry, which was carried out at Sapienza University of Rome, Italy, under the direction of Michael Lederer, founder and first editor of the Journal of Chromatography. In 1983-1984, he worked with Csaba Horvath, the pioneer of HPLC, at the Department of Chemical Engineering at Yale University, New Haven, Connecticut, where he initiated his first investigations on the HPLC of proteins and peptides, which he continued at the Institute of Chromatography of CNR after he returned to Italy. 

M. T. Bowser, G. M. Bebault, X. Peng, and D. D. Y. Chen, Redefining the Separation Factor Pathway to a Unified Separation Science, Electrophoresis 1997,18, 2928. The conventional equation is resolution = ( )(i + J, where ct is relative retention, k 2 is the capacity factor for the more retained component, and k w is the average capacity factor for the two components. This expression is equivalent to (-y — 1) for closely spaced peaks for which... 

Chromatography and electrophoresis (separation according to electrical charge) are used extensively in medical research and forensic science laboratories to separate a variety of mixtures (Figure 2.27). 

Among the electrophoretic methods of chiral resolution, various forms of capillary electrophoresis such as capillary zone electrophoresis (CZE), capillary isotachophoresis (CIF), capillary gel electrophoresis (CGE), capillary isoelectric focusing (CIEF), affinity capillary electrophoresis (ACE), and separation on microchips have been used. However, in contrast to others, the CZE model has been used frequently for this purpose [44]. On the other hand, drawbacks associated with the electrophoretic technique due to lack of development of modem chiral phases have limited the application of these methods. Moreover, the electrophoretic techniques cannot be used at the preparative scale, which represents an urgent need of chiral separation science. 

The discovery of semiconductor integrated circuits by Bardeen, Brattain, Shockley, Kilby, and Noyce was a revolution in the micro and nano worlds. The concept of miniaturization and integration has been exploited in many areas with remarkable achievements in computers and information technology. The utility of microchips was also realized by analytical scientists and has been used in chromatography and capillary electrophoresis. In 1990, Manz et al. [1] used microfluidic devices in separation science. Later on, other scientists also worked with these units for separation and identification of various compounds. A proliferation of papers has been reported since 1990 and today a good number of publications are available in the literature on NLC and NCE. We have searched the literature through analytical and chemical abstracts, Medline, Science Finder, and peer reviewed journals and found a few thousand papers on chips but we selected only those papers related to NLC and NCE techniques. Attempts have been made to record the development of microfluidic devices in separation science. The number of papers published in the last decade (1998-2007) is shown in Fig. 10.1, which clearly indicates rapid development in microfluidic devices as analytical tools. About 30 papers were published in 1998 that number has risen to 400 in... 

The early phase of development can be characterized by a transfer of concepts from conventional CE to the planar format, such as capillary gel electrophoresis, micellar electrokinetic chromatography, sample stacking and pre- and postcolumn sample derivatization. Emphasis was laid on the demonstration of the specific advantages mainly from the separation science point of view. With only very few exceptions, detection has received much less attention yet. LIF detection with confocal imaging has been used in most of the early work owing to its high sensitivity and its relatively easy implementation. If not explicitly mentioned otherwise, all experiments described in the following sections were carried out with LIF detection [28,29]. 

Issaq HJ (2001) The role of separation science in proteomics research. Electrophoresis 22 3629-3638... 

Legido-Quigley C, Marlin ND, Mehn V, Manz A, and Smith NW. Advances in capillary electrochromatography and micro-high performance liquid chromatography monolithic colunms for separation science. Electrophoresis 2003 24 917-944. 

Most real samples that are analysed are, unless they have been deliberately purified (and even then they may still be), actually made up from a number of different chemicals this is certainly trae for most colorants. As has already been discussed when considering molecular spectroscopy techniques, analysis of mixtures can lead to complex, incomplete or even unrcsolvable data. The answer/solution to problems of this type normally involves separation science, where there is selective or differential interaction/behaviour of the different components in the separation system. The principle separation sciences are chromatography and electrophoresis. 

Giddings, J. C. "Generation of Variance, Theoretical Plates, Resolution and Peak Capacity in Electrophoresis and Sedimentation" In Separation Science. 1969, 4, 3, pp 181-189. 

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