Dec 17 2010 01:36 PMElectrophoretic Separations
200 years of Electrophoresis - David Perrett
This brief overview outlines the development of electrophoresis from its first observation some 200 years ago via conventional gels for macromolecule separation and capillary electrophoresis (CE) to current developments centred around lab-on-chip. By definition electrophoresis separates ionic molecules so it is ideal for the separation of simple ions to macromolecules, which are mostly ionic in nature. Most important classes of small biomolecules e.g. amino acids, nucleotides and sugars are highly charged and are easy to separate by electrophoresis. However prior to the development of CE, the application of electrophoresis was limited since it required indirect detection which was at best only semi quantitative and HPLC came to dominate their measurement. Macromolecules, such as RNA, DNA and protein, are readily separated by electrophoresis and conventional electrophoresis still dominates their separation.
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Today electrophoresis remains a very important, if somewhat neglected, analytical technique and is now seen to have three dominant modes i.e. planar, capillary and nano separation formats. However it is just over 200 years since Ferdinand Frederic Reuss published his observations of the migration of colloidal clay particles when an electric field was applied to the solution in which they were suspended1. In the same experiment he also found that there was an opposite flow of water (electroosmosis) associated with the movement of the clay particles. These observations are considered to be the origins of what we now call electrophoresis. In 1816
Porret quantified the flow of water (electroosmosis) through filter paper impregnated with egg albumin. Within a few years of Reuss’s observation the movement of coloured proteins, such as haemoglobin, had been observed. The early history of electrophoresis has been told by Righetti2 and its relevance to the discovery and analysis of proteins has been reviewed by Perrett.
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