Ion-selective carbon paste electrode based on tetraethyl thiuram disulfide for copper(II) and mercury(II)

Tetraethyl thiuram disulfide was chosen as a chemical modifier in a carbon paste electrode for the potentiometric determination of copper(II) and mercury(II) ions. The electrode has wide linear response ranges and rapid response times. The pH influence on the potentiometric response is studied. Selectivity coefficients towards different cationic species are tabulated. The limits of detection are 10^(-7.4) and 10^(-7.6) M for copper (II) and mercury(II) activity, respectively. The electrode is employed in analyses of real samples and in potentiometric titrations. It is successfully used for potentiometric titration of humic acids in order to obtain information about the complexing properties of these acids.