electrophoresis. Plate Heights in CE In chromatography, both longitudinal diffusion and mass-transfer resistance contribute to band broadening. However, because only a single phase is used in electrophoresis, in theory only longitudinal diffusion needs to be considered. In practice, however, Joule heating can add variance as well as the injection process. Although CE is not a chromatographic process, separations are often described in a manncr similar to chromatography. For example, in electrophoresis,