Single-Piece Solid-Contact Polymeric Membrane Ion-Selective Electrodes for Silver Ion

Abstract

Single-piece solid-contact polymeric membrane Ag+ ion-selective electrodes (ISEs) have been fabricated based on conducting polymer poly(3-octylthiophene) (POT) dissolved into the Ag+ ion-selective membrane. The effects of the amounts of POT on the potential responses of the single-piece solid-contact Ag+-ISEs were investigated in detail. Results indicate that the single-piece solid-contact Ag+-ISE with 10 wt% POT displays excellent reproducibility and stability of the potential response. The linear range of 3.0 × 10−8−3.0 × 10−5 M can be obtained in AgNO3 solution with the slope 56.84 ± 0.92 mV/dec (n = 3, R = 0.9984) and the detection limit is 1.90 × 10−8 M. In addition, the single-piece solid-contact Ag+-ISE with 10 wt% POT shows excellent selectivity, stable potential response over a pH range of 3.5 to 6.0 and no significant redox sensitivity. The proposed electrode with 10 wt% POT has been successfully applied to potentiometric titration of chloride ion and determination of Ag+ ion concentrations in spiked waters with high accuracy and good reliability.