Page 58 - Tandem Techniques

Page 40

The different types of flows are illustrated in Figure 1.12. In electrophoretic separations, electro-
osmotic flow can often affect the separation adversely, but it can also be used to advantage in placing
samples onto the capillary electrophoretic system.

Capillary Electrophoresis Apparatus

A diagram of the basic instrument used for capillary electrophoresis is shown in Figure 1.13. It consists
of two reservoirs, one carrying the anode and anode electrolyte, and the other the cathode and cathode
electrolyte.

Figure 1.13
Capillary Electrophoresis Apparatus

Each end of a fused quartz capillary dips into two reservoirs, thus joining them electrically. At one end
of the tube, there is a 'T' join connecting to another reservoir containing the sample solution and, at the
other end, a detector. The capillary is usually a polymer-coated fused silica tube and the detector
consists of a small section of a similar tube, from which the polymer coating has been removed.
Detection is achieved by a variety of procedures, the most common being the adsorption of UV light by
the solutes as they pass the aperture in the polymer coating, usually employing