Abstract: | The various types of convection possible in an electrophoresis device are indicated and criteria are presented from which estimates can be made of the importance of convection in the separation. These criteria also indicate design options possible to suppress or reduce convection effects.Specific consideration is then given to the convection induced by Joule heating in a representative continuous-flow electrophoresis configuration. Detailed solutions for the associated velocity and temperature distributions are presented and it is shown how they are influenced by the buffer through-put, wall cooling, and electric field intensity.Significant distinction is pointed out between counter- and co-flow operation. With the latter mode it would appear that larger gap devices could be successfully run in a normal gravitational environment. |