capillary zone electrophoresis (CZE)

Principle

The basic components of a CZE sytem include:

• a fused silica capillary connecting 2 electrolyte buffer reservoirs
• a high voltage power supply
• a detector penetrating the capillary linked to a data aquisition system

Methods

The sample is introduced into the capillary inlet (near one of the two electrolyte reservoirs). When a high voltage is applied across the capillary ends, the sample molecules are separated by electro-osmotic flow. A bulk flow results from excess positive ions at the inner capillary surface moving towards the cathode. Positive ions in the specimen emerge early at the capillary outlet because the electro-osmotic flow & ion movement are in the same direction. Negative ions also move toward the capillary outlet, but at a slower rate. As the sample ions migrate toward the capillary outlet, they pass a detector penetrating the capillary.

Different types of detectors include:

• optical
• conductivity
• electrochemical
• mass spectroscopy
• radioactivity

More general terms

• electrophoresis