Potential-driven chromatography

Electrophoretic techniques are widely used in biochemistry, especially for separation of nucleotides and proteins. The electrophoretic separation can be carried out in an electrolyte solution with dose to physiological conditions, allowing the compounds to maintain their biological activity. The electrophoretic techniques can be divided into three main groups the traditional gd electrophoretic techniques and the more recent capillary electrophoresis (CE) and potential-driven chromatography (dectrochromatography) techniques. 

Gel electrophoresis (GE) was developed in the 1940s, while capillary electrophoresis appeared 40 years later. Then chromatography with electric potential-driven liquid flow also developed into micellar electroldnetic chromatography (MEKC) and electrochromatography (EC), both with capillary columns. Electrophoresis, thus, is not a chromatographic technique, since there is no stationary phase, except in MEKC and EC. 

Three main aims have driven these studies the use of temperature as a variable to optimize separations, an interest in improved efficiency, and the potential for green separations methods, such as superheated water chromatography, which can eliminate the organic solvent from the mobile phase. 

An interesting article by Anderson has described the potential of AFM in chromatography and microfluidics as it could provide shear-driven pumping of fluid, a mechanism for injecting samples, imaging of the liquid surfaces in the microchannels and, finally, removal of samples for further spectral analysis. ... 

Electroosmotic flow has emerged as a viable alternative transport mechanism to pressure-driven flow in column chromatography. Benefits include a plug-flow profile (reduced transaxial contributions to zone broadening) and a mobile phase velocity that is independent of the column length and particle size. The electroosmotic-driven flow is governed by the dielectric constant of the mobile phase, the zeta potential at the stationary phase/mobile phase interface, and the applied electric field. The efficiency obtainable is limited by double layer overlap or radial dispersion induced by inefficient heat dissipation. 

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