DETERMINATION OF COPPER, NICKEL, ZINC, COBALT AND MANGANESE IN SEAWATER BY CHELATION ION CHROMATOGRAPHY

Preconcentration and determination of trace elements in seawater by chelation ion chromatography (CIC) was studied. For the retention of metal ions (0.25-0.30 M), ammonium acetate (at pH 4.8-5.1) and macroporous iminodiacetate chelating resin were used, This system (CIC) permits trace and ultra-trace determination of metals in a variety of complex matrices, in particular those with a high content of alkali and alkaline earth metals. Detection limits range from 0.1 to 0.5 ng. Satisfactory results are obtained in the range 0.05-0.5 mug/l when 60 ml of sample are preconcentrated. In this work the contents of zinc, copper, nickel, cobalt and manganese in seawater from the Venice lagoon are presented. The results obtained by chelation ion chromatography are compared with those obtained using preconcentration of metals with dithizone and ammonium pyrrolidinedithiocarbamate in chloroform and analysed by graphite furnace atomic absorption spectrometry.