Abstract: The sample was injected into a stream of 0.1 M HNO3 (0.38 mL min-1) and 0.1 mM fluorescein - 1.5 mM KBrO3 (0.12 mL min-1) in a coiled PTFE tube (0.25 mm i.d.) at 60°C. After 68.4 s, 225 mM NaOH (0.3 mL min-1) was added and the absorbance was measured at 530 nm. All the above solution were in aqueous 50% ethanol. The calibration graphs were rectilinear for 30 to 430 µmol of Cl-, 0.3 to 5 nmol of Br- and 0.3 to 5.7 nmol of I-, with detection limits of 10, 0.1 and 0.1 nmol for Cl-, Br- and I-, respectively when the method was used for post-column detection of Br- in bromvaletone, recoveries of 94.2 to 99.8% were obtained. A block diagram of the flow injection system is given.