Methods for reducing peak broadening associated with the establishment of a run field in a capillary electrophoresis process, and apparatus useful for carrying out such methods, are described. Such methods include defining a maximum ramp rate to be used during an initial electric field ramp, defining a minimum period over which the run field is established, and/or maintaining a temperature of a separation medium to within certain ranges during the initial electric field ramp. In addition, methods for determining a ramp rate effective for reducing peak broadening are disclosed.