Speciation of copper, lead and cadmium in aquatic systems by circulating dialysis combined with flame AAS

The assessment of free Cu(II), Pb(II) and Cd(II) ions in the presence of complexed species was realised by a circulating dialysis with Cuprophan planar membranes and subsequent quantification by flame atomic absorption spectrometry. The effect of the flow rate, the time of equilibration, pH and the presence of various complexing agents in the donor solutions were studied. The determination of free Cu(II), Pb(II) and Cd(II) ions in the presence of soil humic substances resulted from the above studies.