The former gels work as they do in conventional gel electrophoresis, yet elution detection is possible. The latter are essentially networks of entangled polymers in solution. These are visous fluids that can be used to rinse and fill the capillary, such that the sieving matrix can be renewed at any time deemed necessary. In both cases the mechanism of separation is sieving, and in both cases the highly automated instrumentation of CE is utilized. A problem with static gels in CGE is extrusion of the gel from the capillary, an irreversible process resulting in failure of the capillary.
Replacement is expensive.
For this reason, dynamic sieving media are preferable when they are appropriate to the sample.