Flow injection was used in combination with chemiluminescence detection to determine greater-than-or-equal-to 30 amol of ascorbic acid based on a luminol-Fe3+-hydrogen peroxide system. The method was applied to the determination of ascorbic acid in pure form, pharmaceutical preparations and fruit juices. The method is sensitive, rapid (sampling rate 2-56 samples h-1) and tolerates the presence of common ingredients usually found in fruit juices and drug formulations.