Question

Topic II. Separations methods in the CH455 lab.

Describe how the capillary electrophoresis experiment is able to separate both charged and neutral species using electrophoretic and electroosmotic modes of separation. Use diagrams to assist in both the description of the phenomena and provide representative examples of separations achieved with CE.

Answer 1

Capillary electrophoresis is an analytical technique that separates ions based on their electrophoretic mobility with the use of an applied voltage. The electrophoretic mobility is dependent upon the charge of the molecule, the viscosity, and the atom's radius. The rate at which the particle moves is directly proportional to the applied electric field--the greater the field strength, the faster the mobility. Neutral species are not affected, only ions move with the electric field. If two ions are the same size, the one with greater charge will move the fastest. For ions of the same charge, the smaller particle has less friction and overall faster migration rate. Capillary electrophoresis is used most predominately because it gives faster results and provides high resolution separation. It is a useful technique because there is a large range of detection methods available.1