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

Abstract

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,N0,N0-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.