Accumulation of Cu(II) cations in poly(3,4-ethylenedioxythiophene) films doped by hexacyanoferrate anions and its application in Cu 2+-selective electrodes with PVC based membranes

Abstract

Electrochemical properties of poly(3,4-ethylenedioxythiophene) doped with hexacyanoferrate(II,III) ions (PEDOT(HCF)) were studied in the presence of Cu 2+ ions. Voltammetric and EDAX studies revealed retention of hexacyanoferrate anions in the polymer film and accumulation of Cu(II) cations, as well as formation of solid copper hexacyanoferrate near the polymer surface. Accumulation of Cu 2+ ions was found to be advantageous from the point of view of PEDOT(HCF) applications as a solid contact (ion-to-electron transducer) in all-solid-state Cu 2+-selective electrodes with solvent polymeric polyvinyl chloride (PVC) based membrane, containing Cu 2+-selective ionophore. Binding of Cu 2+ ions in the conducting polymer layer results in analyte ions flux into the transducer phase. Thus, pronounced enhancement of selectivity of the all-solid-state Cu 2+-selective electrode or lower detection limit of the potentiometric response range was achieved, reaching under optimised conditions 10 −7 M CuSO 4.