Thin layer electrochemical extraction of non-redoxactive cations with an anion-exchanging conducting polymer overlaid with a selective membrane

Si, Pengchao; Bakker, Eric

doi:10.1039/b907893b

Cited by 50 publications

(67 citation statements)

References 9 publications

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“…In particular, it was also shown by reflectometry experiments that such an ion to electron transducing material effectively suppresses the occurrence of a thin water layer between the ion-selective membrane and the internal redox element 21. Consequently, reversible and well behaved thin layer electrochemistry has been demonstrated with sandwich materials composed of this conducting polymer overlaid with an ion-selective polymeric membrane 22, 23…”

Section: Resultsmentioning

confidence: 99%

High-Temperature Potentiometry: Modulated Response of Ion-Selective Electrodes During Heat Pulses

et al. 2009

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The concept of locally heated polymeric membrane potentiometric sensors is introduced here for the first time. This is accomplished in an all solid state sensor configuration, utilizing poly(3-octylthiophene) as intermediate layer between the ion-selective membrane and underlying substrate that integrates the heating circuitry. Temperature pulse potentiometry (TPP) gives convenient peak-shaped analytical signals and affords an additional dimension with these sensors. Numerous advances are envisioned that will benefit the field. The heating step is shown to give an increase in the slope of the copper-selective electrode from 31 mV to 43 mV per 10-fold activity change, with a reproducibility of the heated potential pulses of 1% at 10 µM copper levels and a potential drift of 0.2 mV/h. Importantly, the magnitude of the potential pulse upon heating the electrode changes as a function of the copper activity, suggesting an attractive way for differential measurement of these devices. The heat pulse is also shown to decrease the detection limit by half an order of magnitude.

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Section: Resultsmentioning

confidence: 99%

High-Temperature Potentiometry: Modulated Response of Ion-Selective Electrodes During Heat Pulses

et al. 2009

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“…Our thin-layer voltammetric approach is simpler than that of Bakker and co-workers, who supported a thin ionophore-doped PVC membrane by the reduced form of a poly(3-octylthiophene) membrane as a voltammetric ion-to-electron transducer for membranous cations. 29 Accordingly, their approach required the initial presence of an analyte cation in the PVC membrane, which must be doped with anionic sites as counter ions. Moreover, an amount of anionic sites had to be controlled carefully to obtain voltammetric responses to multiple cations.…”

Section: Resultsmentioning

confidence: 99%

Voltammetric Mechanism of Multiion Detection with Thin Ionophore-Based Polymeric Membrane

Greenawalt

Amemiya

2016

Anal. Chem.

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The capability to detect multianalyte ions in their mixed solution is an important advantage of voltammetry with an ionophore-based polymeric membrane against the potentiometric and optical counterparts. This advanced capability is highly attractive for the analysis of physiological ions at millimolar concentrations in biological and biomedical samples. Herein, we report on the comprehensive response mechanisms based on the voltammetric exchange and transfer of millimolar multiions at a thin polymeric membrane, where an ionophore is exhaustively depleted upon the transfer of the most favorable primary ion, IzI. With a new volt-ammetric ion-exchange mechanism, the primary ion is exchanged with the secondary favorable ion, JzJ, at more extreme potentials to transfer a net charge of |zJ|/nJ – |zI|/nI for each ionophore molecule, which forms 1:nI and 1:nJ complexes with the respective ions. Alternatively, an ion-transfer mechanism utilizes the second ionophore that independently transfers the secondary ion without ion exchange. Experimentally, a membrane is doped with a Na+- or Li+-selective ionophore to detect not only the primary ion, but also the secondary alkaline earth ion based on the ion-exchange mechanism, where both ions form 1:1 complexes with the ionophores to transfer a net charge of +1. Interestingly, the resultant peak potentials of the secondary divalent ion vary with its sample activity to yield an apparently super-Nernstian slope as predicted theoretically. By contrast, the voltammetric exchange of calcium ion (nI = 3) with lithium ion (nJ = 1) by a Ca2+-selective ionophore is thermodynamically unfavorable, thereby requiring a Li+-selective ionophore for the ion-transfer mechanism.

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“…Because the SC‐ISEs have shown attractive analytical characteristics in open circuit potentiometry as well as in dynamic electrochemistry, new materials and new concepts have been widely investigated in recent years . Freely dissolved electroactive materials in the sensing films or covalent attachment of the redox center to the polymeric matrix have been explored.…”

Section: Introductionmentioning

confidence: 99%

Ion Transfer Voltammetry at Thin Films Based on Functionalized Cationic [6]Helicenes

et al. 2017

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We describe a new family of molecular ion‐to‐electron redox probes based on cationic diaza, azaoxa, and dioxa [6]helicenes and their derivatives. Their unique structure combines, in a single framework, two privileged families of molecules – helicenes and triaryl methyl carbenium moieties. These cationic [6]helicenes exhibit reversible and reproducible oxidation/reduction behavior and facilitate the ion transfer into thin layer sensing films composed of bis(2‐ethylhexyl)sebacate (DOS), polyurethane (PU), sodium tetrakis 3.5‐bis(trifluoromethyl)phenyl borate, sodium ionophore X and diaza+(C8)2Br2 for cation transfer. Cyclic voltammetry is used to interrogate the thin films. The cationic response can be tuned by adjusting the membrane loading. Addition of lipophilic cation exchanger into the membrane film results in transfer waves of Gaussian shape for cations. A peak separation of 60 mV and peak width of 110 mV are near the theoretical values for a surface confined process. While Nernstian shifts of the peak potentials with analyte concentration is obtained for membranes based on cationic [6]helicenes and doped with sodium‐selective ionophore X, this ionophore was found to promote a gradual loss of redox active species from the ionophore‐based membranes into the sample solution.

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Thin layer electrochemical extraction of non-redoxactive cations with an anion-exchanging conducting polymer overlaid with a selective membrane

Abstract: We report here on the selective voltammetric cation transfer into a polymeric thin layer film that is back side contacted with an anion-exchanging conducting polymer, poly(3-octylthiophene).

Cited by 50 publications

References 9 publications

High-Temperature Potentiometry: Modulated Response of Ion-Selective Electrodes During Heat Pulses

High-Temperature Potentiometry: Modulated Response of Ion-Selective Electrodes During Heat Pulses

Voltammetric Mechanism of Multiion Detection with Thin Ionophore-Based Polymeric Membrane

Ion Transfer Voltammetry at Thin Films Based on Functionalized Cationic [6]Helicenes

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