Conducting polymer-coated electrode as a reference/counter electrode in an organic phase and its application to a two-electrode type thin-layer cell for voltammetry at the liquid | liquid interface.

An indium tin oxide glass electrode coated with poly(3,4-ethylenedioxythiophene), PEDOT, PEDOT-ITOE, was proposed as an electrode workable as both a reference electrode and a counter one, a reference/counter electrode, in an organic phase and applied to a thin-layer cell of a two-electrode system for voltammetry at the liquid | liquid interface. By oxidizing the PEDOT film by 50% and doping a supporting electrolyte anion in an organic phase into the PEDOT film, a suitable depolarization was realized at the PEDOT | organic phase interface. The partially oxidized PEDOT-ITOE showed a Nerntian response to the supporting electrolyte anion concentration in the organic phase. The electrode potential was stable within +/-3 mV for 12 h, and showed a consistent value among the PEDOT-ITOEs prepared under the same procedure (the error range was about 7 mV, n = 8).