A flow-injection/Donnan dialysis/differential pulse anodic stripping voltammetry system was developed for the determination of free cadmium concentrations, Cd2+, in solutions containing organically complexed Cd(II). A small dialysis cell with a strong cation-exchange membrane separating the sample and the receiver channels, was equilibrated in a flow-injection system. The ionic strength of sample and receiver solutions was 0.1 M, with NaNO3as the bulk electrolyte. By determining a constant fraction of the Cd2+associated with the membrane phase, Cd2+ of the samples could be measured.
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