Sensitivity enhancement of PVC membrane based perrhenate ion-selective electrode by attaching anionic polyelectrolyte solution layer

A perrhenate ion-selective electrode based on a plasticized poly(vinyl chloride) membrane containing an ion-pair of perrhenate ion with a hydrophobia quaternary ammonium ion was fabricated and its performance was examined with respect to sensitivity mainly. The electrode using tridodecylhexadecylammonium and 2-nitrophenyl octyl ether as the ion exchanger and the plasticizer, respectively, was found to show a best performance with a lower detection limit of 2.0 × 10^-7 M (M = mol dm^-3) of perrhenate ion. Another electrode with a preconcentration function was newly constructed by attaching an aqueous solution layer of an anionic polyelectrolyte, poly(diallyldimethylammonium) chloride on the surface of the electrode membrane by use of a dialysis membrane. The lower detection limit of the newly constructed electrode was much improved by about two orders of magnitude. The response time of the electrode was about 6-10 min, and it was longer than that of the electrode without the polyelectrolyte solution layer.