A chemiluminescent method for the determination of Cu in natural water has a detection limit of 0.09 ppb and a recovery of 91.4-108%. The results determine by the method are comparable with those by graphite furnace atomic absorption spectrometry. The optimum conditions of the chemiluminescent system include a solution containing o-phenanthroline [66-71-7] 9.25 ?10-7, H2O2 0.56, cetyltrimethylammonium bromide [57-09-0] 1.63 ?10-3, KOH 5.03 ?10-3 mL/dm3, and Cu at ppb levels.

Key words: REACTION MECHANISM, WATER QUALITY ANALYSIS, COPPER, COPPER ION, QUATERNARY SYSTEM, HYDROGEN PEROXIDE, PHENANTHROLINE, SIMPLEX ALGORITHM, CHEMILUMINESCENCE REACTION, POTASSIUM HYDROXIDE