[Determination of copper and cadmium in water by continuous flow analysis]

A continuous flow analysis system for the preconcentration of Cu2+ and/or Cd2+ in water was developed. Trace copper or cadmium in water could be concentrated on activated carbon particles packed in micro column at pH > or = 9.0. The adsorbed analyte was eluted with 0.5 ml 2.5% nitric acid and determined by flame atomic absorption spectrometry. A sample size of 10-25 ml sufficed for the determination of copper2+ or cadmium at a level as low as microgram/L. The relative standard deviation of 6 parallel determinations was 4.3% for copper and 11% for cadmium. The proposed method was applied to the determination of copper and cadmium in natural water with a recovery of 84.4%-118%.