FLOW-INJECTION ONLINE PRECONCENTRATION AND FLAME AAS DETERMINATION OFCOPPER, CADMIUM AND LEAD IN MARINE SEDIMENT SAMPLES

A rapid and sensitive AAS method is described for the determination of copper, cadmium and lead based upon on-line preconcentration on a mic rocolumn packed with C-18 material. These heavy metals are complexed w ith dithizone from ammonical solutions in the flow injection system an d adsorbed on the column. The preconcentrated species were eluted with acidified methanol (pH greater than or equal to 2) and injected direc tly into the nebulizer for atomization in an air-acetylene name for me asurement. The retention efficiency was better than 98% resulting in s ensitivity enhancement factors of 80, 90 and 60 for 10 ml sample conta ining copper, cadmium and lead, respectively. The respective detection limits are 1.2, 0.6 and 3.0 ppb for copper, cadmium and lead. The thr oughput of the samples was found to be 30/h, with a loading time of 1 min. The method has been applied to the analysis of marine sediment sa mples.