A detection interface has been designed to allow for the addition of postcolumn reagents to evaluate chemiluminescence as a method of detection for capillary electrophoresis. The interface utilizes a reactor that introduces reagents into the electrophoretic system in a sheathing flow profile. The reaction conditions including pH, concentration, and flow rates of the reagents for acridinium chemiluminescence have been studied to evaluate the effect on the detector response. The detection limit for the Interface was found to be in the low femtomole to upper attomole range for acridiniums. The interface was evaluated as a potential source of zone dispersion by investigating its effects on band width. "Chemical band narrowing" was observed due to the fast kinetics of the chemiluminescence reaction.