Electrophoresis Electrophoretic effect

Fan et al. [106] developed a high performance capillary electrophoresis method for the analysis of primaquine and its trifluoroacetyl derivative. The method is based on the mode of capillary-zone electrophoresis in the Bio-Rad HPE-100 capillary electrophoresis system effects of some factors in the electrophoretic conditions on the separation of primaquine and trifluoroacetyl primaquine were studied. Methyl ephedrine was used as the internal standard and the detection was carried out at 210 nm. A linear relationship was obtained between the ratio of peak area of sample and internal standard and corresponding concentration of sample. The relative standard deviations of migration time and the ratio of peak area of within-day and between-day for replicate injections were <0.6% and 5.0%, respectively. 

Electrophoresis, Electrophoretic Analysis and Electrophoretic Deposition. Electrophoresis may be defined as the phenomenon of migration of colloidal particles in a liquid due to the effect of an emf or potential difference across immersed electrodes. Most solids, being negatively charged, migrate to the anode, but there are some exceptions. Migrated particles lose their, charge at the electrode, and are deposited on it... 

Electrodecantation — Application of the electrophoretic effect (- electrophoresis) to concentrate a suspension of particles in a liquid by collecting the particles near one of the two electrodes used to apply a voltage across the cell containing the suspension. 

Electrophoresis — Movement of charged particles (e.g., ions, colloidal particles, dispersions of suspended solid particles, emulsions of suspended immiscible liquid droplets) in an electric field. The speed depends on the size of the particle, as well as the -> viscosity, -> dielectric permittivity, and the -> ionic strength of the solution, and it is directly proportional to the applied electric field. In analytical as well as in synthetic chemistry electrophoresis has been employed to separate species based on different speeds attained in an experimental setup. In a typical setup the sample is put onto a mobile phase (dilute electrolyte solution) filled, e.g., into a capillary or soaked into a paper strip. At the ends of the strip connectors to an electrical power supply (providing voltages up to several hundred volts) are placed. Depending on their polarity and mobility the charged particles move to one of the electrodes, according to the attained speed they are sorted and separated. (See also - Tiselius, - electrophoretic effect, - zetapotential). 

Electrophoresis and relaxation were taken to be totally independent phenomena, whereas they are not. As a result the derivation neglected, (i) the effect of the asymmetry of the ionic atmosphere on the electrophoretic effect, and (ii) the effect of electrophoresis on the movement of the ion in an asymmetrical ionic distribution. These are cross terms described below. 

Since the electrophoretic effect manifests itself as a modified viscous drag on the ion by the solvent, the force on the ion due to electrophoresis can be given by Stokes Law. The change in velocity Ay, can then be given in terms of the two Stokes Law terms one for the viscous drag due to the solvent in the absence of electrophoresis, and the other due to the modified viscous drag resulting from electrophoresis. 

In aU of these modifications no account was taken of the need to consider cross terms arising from the effect of relaxation on the electrophoretic effect, and from the effect of electrophoresis on relaxation, but they did hint at the form of the conductance theory put forward later by Fuoss and Onsager. 

Some future developments should include applying pulsed electrophoresis to studies of very small DNA molecules, proteins, macromolecular complexes, cells and synthetic polymers. Fully understanding the physical mechanisms responsible for pulsed electrophoretic fractionation should enable researchers to extend resolution to even larger DNA molecules and fully generalize use of this new electrophoretic effect. 

Free amino acids, proteins, ions, colloidal particles, bacteria, and cells are possible charged particles migrating in an electric field therefore, they can be studied by electrophoresis. As described in Section 7.5, some molecules of the solvent are attached charges on the particle hence, some solvent will move together with the particle. This is a part of the electrophoretic effect. 

The electrokinetics are a class of several different interfacial effects that become important in micron and submicron dimensions. The most important and widespread categories of the electrokinetic effects are the electroosmosis and the electrophoresis. When the ionized liquids are in contact with stationary charged surfaces, counterions accumulate near the surface and buUd a layer that is called the electric double layer (EDL). The presence of an external electric field moves this layer and consequently generates the bulk flow field in the channels. This effect is named as electroosmosis and the generated flow is electroosmotic or electrokinetic flow. The external electric field also moves charged species and macromolecules in the micro- and nanochaimels which is usually referred to electrophoresis or electrophoretic effect. 

The abihty to remove heat from electrophoretic systems has severely limited the maximum capacity of these systems in terms of how large or thick the systems can be. Electrophoretic separations have been performed on space flights because the effect of gravity in outer space is small and mixing from heating is negligible. Whereas electrophoresis in outer space has been accompHshed (10), the economics for a scaleable process have not (see Space processing). 

The heating effect is the limiting factor for all electrophoretic separations. When heat is dissipated rapidly, as in capillary electrophoresis, rapid, high resolution separations are possible. For electrophoretic separations the higher the separating driving force, ie, the electric field strength, the better the resolution. This means that if a way to separate faster can be found, it should also be a more effective separation. This is the opposite of most other separation techniques. 

Electrophoretic condition 60 cm (effective length of 50 cm)x75 p.m I.D. fused capillary column, run buffer borate buffer pH 9,0, P-cyclodextrin, electrophoresis voltage 20 kV, detection at 254 nm. 

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