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 AgNO 3 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. Silver is well known for its excellent antimicrobial property. It has been widely used in medicine, photography and production of ornaments. However, its potential damage to the environment has been easily neglected, although it is not as toxic to humans as other heavy metals. It has been reported that silver salts or silver nanoparticles show unacceptable toxic effects to the environment and human health.1 The U.S. Environmental Protection Agency reported that the amount of Ag + ion higher than 1.6 nM in water is toxic to fish and microorganisms 2 and the maximum contaminant level of total silver in drinking water is limited to 0.9 μM.3 Therefore, it is necessary to detect Ag + ion using efficient analytical methods. Potentiometry with ion-selective electrodes (ISEs) is a promising method for directly determining various ions in clinical, environmental and industrial analysis, owning to their attractive features including simple design, small size, low energy consumption and low cost. Solid-contact ion-selective electrodes (ISEs) have recently attracted considerable attentions for simple fabrication, easy miniaturization and less maintenance, compared to the traditional polymeric membrane ISEs with inner filling solutions. 4 Moreover, solid-contact ISEs can place in any position or configuration without the risk of leakage of the inner solution. However, the coated-wire electrodes (CWEs), 5 as the initial solid-contact ISEs, suffer from the poor potential stability resulting from the blocked interface between the electronic conductor and the ion-selective membrane (ISM). 6 Various materials have been used as solid-contact transducers to improve potential stability of solid-contact ISEs, including hydrogels, 7 redox-active self-assembles monolayers, 8 three-dimensionally ordered macroporous carbon, 9 carbon nanotubes, 10 fullerene, 11 graphene, 12 gold nanoparticles 13 and conducting polymers.14-16 Among these materials, the conducting polymer p...

Real-time monitoring of the dissolution of silver nanoparticles by using a solid-contact Ag+-selective electrode

“…In this work, the compound, o-xylylenebis(N, N-diisobutyldithiocarbamate), was chosen as Ag + ionophore, since it shows very high selectivity toward Ag + [29][30][31], as compared with other Ag + ionophores [32,33]. This means that the proposed ionophorebased solid-contact Ag + -ISE may be useful for monitoring the dissolution of Ag NPs in complex background solutions.…”

Electroanalysis with Membrane Electrodes and Liquid–Liquid Interfaces

“…The group of Qin found that 10% POT can be freely dissolved in the membrane to fabricate ion-selective electrodes for silver ions, with attractive detection limits . The key drawback of this material is the known sensitivity to light.…”

“…The group of Qin found that 10% POT can be freely dissolved in the membrane to fabricate ion-selective electrodes for silver ions, with attractive detection limits. 32 The key drawback of this material is the known sensitivity to light. The old puzzle of why drop cast, electrically neutral POT layers can give such excellent behavior as intermediate transducing layers in potentiometric was unravelled by the groups of De Marco and Bakker.…”

Simultaneous Determination of Na+, K+, Ca2+, Mg2+and Cl−in Unstimulated and Stimulated Human Saliva Using All Solid State Multisensor Platform

“…Currently solid contact ISEs are based on conducting polymers such as PEDOT: PSS and POT . Other constructions are based on molecular redox couples and other materials like gold , platinum and C60 …”