PRECONCENTRATION OF TRACE CU(II), NI(II), CO(II) AND CD(II) ON A MICRO-MEMBRANE FILTER USING PULVERIZED CHELATE RESIN AND ITS DIRECT ASHINGON A GRAPHITE-FURNACE AAS

A new highly effective preconcentration method for Cu(II), Ni(II), Co( II) and Cd(II) in water samples which involves the filtration of these metal ions combined with pulverized Chelex 100 resin using a micro-me mbrane filter (MMF, cellulose nitrate, diameter: 4 mm, pore size: 1.00 mu m) was developed. It was possible to determine these metal ions co llected on the MMF by graphite furnace AAS in which the MMF was introd uced directly into a cup type graphite cuvette. Over 93% of these meta l ions were recovered by the MMF at pH 4.5 for Cu(II) and at pH 6.5 fo r other metal ions. Only a 5 ml sample of the metal ion at less than p pb-level was enough for one analysis. The detection limits (3 sigma of blank solution) for Cu(II), Ni(II), Co(II) and Cd(II) are 45, 95, 30 and 0.95 ppt, respectively. An application of the method for Cu(II), N i(II) and Cd(II) in seawater was also described.