Improvement of the upper limit of the ISE Nernstian response by tuned galvanostatic polarization

• Anodic polarization is used for improving the upper detection limit of ISE.
• Polarization vs. current dependence obeys the Ohm’s law.
• For a Cd2+ISE used as a model system the obtained upper detection limit is 1.0 M.
• Simple algorithm allows for the analytical application of the approach.

Galvanostatic polarization with a tuned anodic current density is successfully applied for the improvement of the upper detection limit (UDL) of a Cd2+-selective electrode with PVC membrane containing neutral ionophore N,N,N′,N′-tetradodecyl-3,6-dioxaoctanedithioamide (ETH 5435). The UDL of the anodically polarized electrode is 1.0 M CdCl2 whereas the traditional zero-current UDL is 0.05 M. The polarization regularities obey the Ohm’s law, and this makes the basis for the algorithm of the optimization of the polarizing current density for a given Cd2+ concentration and for the analytical application of the electrode.

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