CAPILLARY ELECTROPHORESIS

Capillary Electrophoresis



Capillary Electrophoresis

Introduction

Capillary electrophoresis (CE), also known as capillary electrophoresis zone (CZ), can be used for a few types of ionic charge and frictional forces and the masses. In conventional electrophoresis, electrically charged analytes move in a liquid conductor in an electric field. Introduced in 1960 by capillary electrophoresis (CE) has been developed for different species due to their size to charge a small capillary filled with electrolyte. Measuring instruments needed to perform capillary electrophoresis is relatively simple (Altria, 2004, 645).

CE Instrumentation

Source: http://www.pharmacopeia.cn/v29240/usp29nf24s0_c727.html

Electro-osmosis

Electro-osmosis is the phenomenon whereby there is movement of water molecules induced by an electric field in a porous medium, every pore of the material is considered as a capillary that is in contact with water solution containing ions, porous materials as well as ground and used in building construction are often laden with negative charge, but in the vicinity of the walls are positive ions or cations, which is why it forms a double layer, consists of a fixed layer for cations absorbed by the surface (wall) and a mobile or diffuse layer, if electrodes are introduced and applied power differential, moving layer will move towards the negative electrode or cathode, carrying water molecules, this movement of water transport is what is called electro-osmosis(Kaiser, 2004, 2044).

Discussion

Analytes in Capillary Electrophoresis

Migration of analytes is started by an applied electric field between the destination and source vials and fed to the electrodes supply. It is important to note that all ions, negative or positive, passing through the capillaries in the same direction, change of electro- osmosis as will be explained. The electro-osmotic flow resulting from the diffuse layer is uniform and has a profile Narrow unlike that associated with systems using an applied pressure to elute the analytes (HPLC). The electro-osmotic flow does not because significant widening of the band. The detector output is sent to output devices and processing, such as an integrator or computer (Altria, 2004, 645).

Source: http://people.stfx.ca/tsmithpa/Chem362/labs/CE.html

Theoretical Plates and Resolution

Most commercial systems use UV or UV-absorption of the main methods of detection. In these systems, some of the capillaries are used as detection cell. Screening for the detection of analytes separated without loss of resolution. Part of the capillary for detection of ultraviolet rays, however, must be optically transparent.

Main Features of Capillary Electrophoresis

Capillary electrophoresis (CE) is the most used because of their operational simplicity and versatility. The range of applications of Capillary Zone Electrophoresis is diverse and its application range from the problems that are related to the separation of small species to the separation of large species. This, coupled with the fact small required sample volumes, has aroused great expectations in different fields, as evidenced by the increase in publications in the area biochemistry and biotechnology, pharmaceutical, laboratory or environment. The capillary and the vials are filled with an electrolyte with buffering capacity (Akbay, 2005, 1672).

Advantages and Disadvantages of Capillary Electrophoresis

One of the main advantages of CE is that it requires only simple instrumentation. Capillary electrophoresis is a very powerful technique combining ...