Enhancing EMF stability of solid-state ion-selective sensors by incorporating lipophilic silver-ligand complexes within polymeric films

Liu, Dong; Meruva, Ravi K.; Brown, Richard B.; Meyerhoff, Mark E.

doi:10.1016/0003-2670(95)00583-8

Cited by 66 publications

(50 citation statements)

References 15 publications

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“…Unfortunately, coated wire electrodes show long-term potential instability, which is attributed to the lack of a well-defined interface between the ionically conductive sensing membrane and the electronically conductive conductor and the formation of a thin water layer between them [2,3]. By incorporation of appropriate redox-active compounds to the ISE membranes [4,5] or using conducting polymers (CPs) such as polypyrrole, poly(3-octylthiophene), polyaniline and poly (3,4-ethlyenedioxythiophene) as solid contacts [6], the potential stabilities of all-solid-state ISEs can be largely improved. However, these methods may still suffer from problems of the presence of the water layers, undesired side reactions with redox interferences and sensitivity to light, dissolved oxygen and CO 2 [6,7].…”

Section: Introductionmentioning

confidence: 99%

An all-solid-state polymeric membrane Pb2+-selective electrode with bimodal pore C60 as solid contact

Yin

Qin

2015

Analytica Chimica Acta

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Section: Introductionmentioning

confidence: 99%

An all-solid-state polymeric membrane Pb2+-selective electrode with bimodal pore C60 as solid contact

Yin

Qin

2015

Analytica Chimica Acta

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“…It was, however, reported that their long-term potential stability was limited and they were, therefore, useful only in specific applications such as detectors for capillary electrophoresis [14] or in flow-injection analysis [15]. Their potential instability was attributed to lack of control of the concentrations of the species defining the redox potential at the membrane/metal interface [12,16,17] and their response characteristics were successfully improved by adding an appropriate redox-active component to the PVC membrane [18] or by using an intermediate redox-active polymer layer [19]. Similarly, the presence of a redox-active self-assembled monolayer (SAM) between the polymeric membrane and the inner Au electrode also leads to very stable systems [20,21].…”

Section: Introductionmentioning

confidence: 99%

A polypyrrole-based solid-contact Pb2+-selective PVC-membrane electrode with a nanomolar detection limit

et al. 2004

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Ion-selective electrodes (ISE) based on conventional plasticized PVC membranes with solid inner contact (SC) have so far had unsatisfactory lower detection limits. Here it is shown that electropolymerization of pyrrole in the presence of potassium hexacyanoferrate(II)/(III) on Pt results in adequate inner contact for SC-ISE. The nanomolar lower detection limit achieved with the Pb 2+ -selective PVC membranes investigated is comparable with values obtained with optimized internal solutions of liquid-contact ISE.

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“…Therefore, the development of junction-free, all solid-state reference electrodes and solid-contact ISEs of high stability is of great importance (27). Membranes with the same selectivity toward all anions and cations are the ideal candidates for a junctionfree reference electrode.…”

Section: Microfabricated Reference Electrodesmentioning

confidence: 99%

Microfabricated Potentiometric Electrodes and Their In Vivo Applications.

Lindner

Buck²

2000

Anal. Chem.

107

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New technologies are yielding mass-produced, miniature, ion-selective electrodes that can be routinely used in biology E = (ε 1 + ε 2 + ε 3 + ε 4 + ε 5 ) + ε j + (ε´+ ε´´) = E o + ε j + ε M (1) in which E o is a constant potential term comprising the potential contributions ε 1 to ε 5 , which arise within the system from the two reference electrodes in the cell; ε j is the liquid junction potential; and ε M is the membrane potential. We usually seek electrolyte combinations for the reference electrode in which ε j is nearly zero. The essential part of an ISE is the ion-sensitive membrane that is commonly placed between two aqueous phases-for example, the sample and the inner electrolyte solution. Ion-selective membranes made from glass, single crystals (e.g., LaF 3 ), pressed pellets of insoluble precipitates (e.g., AgCl, AgBr, AgI), or solvent polymeric membranes (highly plasticized polymeric films, also known as liquid membranes) are widely used in analytical practice. In this article, we will focus our discussions on microfabricated ISEs based on solvent polymeric or liquid membranes.Typically, the membrane potential is divided into three separate potential contributions-the phase boundary potentials at both interfaces (ε´and ε´´) and the diffusion potential within the ion-selective membrane (3-5). However, the membrane's internal diffusion potential is zero if there are no concentration gradients within the membrane. The basic equation for the interfacial potentials εá nd ε´´is in which R is the gas constant, T is the absolute temperature, F is the Faraday constant, z i is the charge number of the primary ion i, k i is the single-ion partition coefficient, and a i and ā i are the primary ion solution and membrane activities, respectively. The phase boundary potential is a simple function of the sample ion activities only when ā i is not influenced significantly by the sample. Accordingly, for an ideally selective membrane, the membrane potential is directly related to the respective activities in the contacting solutions in which a i (1) and a i (2) are the ion activities in the sample and the inner filling solution, respectively. A Nernstian response is expected in a potentiometric cell when the liquid junction potential can be neglected and the inner filling solution of the electrode is kept constant:Most of the microfabricated ion sensors are based on solvent polymeric or liquid membranes. Overplasticized poly(vinyl chloride) (PVC) is most frequently used as the membrane matrix. The selectivity of these membranes is determined by the dielectric properties of the plasticizer and the selective, hydrophobic complexing agents, which are neutral or charged carriers (ionophores), within the membrane phase. A comprehensive review of the carrier-based ISEs and bulk optodes was published recently (6, 7).Calibrating ISEs by serial dilution gives a plot of the cell voltage as a function of the logarithm of the primary ion activity, as shown in Figure 2. It is linear over a wide concentration range (generally from...

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Enhancing EMF stability of solid-state ion-selective sensors by incorporating lipophilic silver-ligand complexes within polymeric films

Cited by 66 publications

References 15 publications

An all-solid-state polymeric membrane Pb2+-selective electrode with bimodal pore C60 as solid contact

An all-solid-state polymeric membrane Pb2+-selective electrode with bimodal pore C60 as solid contact

A polypyrrole-based solid-contact Pb2+-selective PVC-membrane electrode with a nanomolar detection limit

Microfabricated Potentiometric Electrodes and Their In Vivo Applications.

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