A comparative study on the preconcentration of some metal ions in water samples with Cu(II) and Ni(II) salicylaldoxime coprecipitants

New separation and preconcentration procedures based on the coprecipitation of Fe(III) and Pb(II) ions with Cu(II) salicylaldoxime coprecipitant and of Cu(II) with Ni(II) salicylaldoxime coprecipitant were studied comparatively. The coprecipitation conditions for each method, such as the effect of the pH, the amounts of carrier elements and reagent, sample volume and matrix effects were examined in detail. The determinations of analyte ions were performed by flame AAS. Under optimised conditions the detection limits of the methods (3s/b) were 1.58, 3.56 and 1.32 mu g L-1 for iron(III), lead(II) an copper(II), respectively. The precision (as RSD %) of the methods was a parts per thousand currency sign3.2%. Each method was validated by both spiked tap water, dam water samples and by the analysis of certified reference material (TMDA-54.4 fortified lake water). It was found that the recovery of Fe(III), Pb(II) and Cu(II) from the water samples was a parts per thousand yen90%.