Abstract: The sample solution (52 µL) was injected into a stream of 50 mM polyphosphoric acid (2.3 mL min-1) and passed through a tube (24 cm x 0.9 mm), before mixing with a stream of 10 µM-KMnO4 (2.3 mL min-1). The mixed streams were passed through a reaction coil of glass tubing (34 cm x 2.3 mm) and chemiluminescence was measured. Log. - log. calibration graphs were rectilinear from 10 nM (detection limit) to 0.1 mM buprenorphine hydrochloride(I). In the determination of 10 µg mL-1 of I, the coefficient of variation was 0.7% (n = 10). The method was applied to tablets containing 0.2 mg of I.