Responses of site-controlled, plasticized membrane electrodes

Lindner, Ernő; Graf, E.; Niegreisz, Zsuzsa; Tóth, Klára; Püngor, E.; Buck, Richard P.

doi:10.1021/ac00155a004

Cited by 182 publications

(102 citation statements)

References 22 publications

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“…Accurate ionic site control, however, requires a simple method for the determination of ionic sites in solvent polymeric membranes and membrane components. Unfortunately, most of these methods are quite cumbersome and cannot be easily adapted for screening the ionic site concentration in novel membrane matrices and plasticizers [43][44][45][46][47][48]. More recently, a simple spectrophotometric method was developed for the fast and accurate determination of ionic site concentrations (covalently attached functionalized groups and/or ionic impurities) in plasticized polymeric membranes and membrane plasticizers [49].…”

Section: Determination Of the Concentration Of Charged Sites In Solvementioning

confidence: 99%

Performance evaluation criteria for preparation and measurement of macro- and microfabricated ion-selective electrodes (IUPAC Technical Report)

Lindner¹,

Umezawa

2008

Pure and Applied Chemistry

232

168

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Over the last 30 years, IUPAC published several documents with the goal of achieving standardized nomenclature and methodology for potentiometric ion-selective electrodes (ISEs). The ISE vocabulary was formulated, measurement protocols were suggested, and the selectivity coefficients were compiled. However, in light of new discoveries and experimental possibilities in the field of ISEs, some of the IUPAC recommendations have become outdated. The goal of this technical report is to direct attention to ISE practices and the striking need for updated or refined IUPAC recommendations which are consistent with the state of the art of using macro- and microfabricated planar microelectrodes. Some of these ISE practices have never been addressed by IUPAC but have gained importance with the technological and theoretical developments of recent years. In spite of its recognized importance, a generally acceptable revision of the current IUPAC recommendations is far beyond the scope of this work.

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Section: Determination Of the Concentration Of Charged Sites In Solvementioning

confidence: 99%

Performance evaluation criteria for preparation and measurement of macro- and microfabricated ion-selective electrodes (IUPAC Technical Report)

Lindner¹,

Umezawa

2008

Pure and Applied Chemistry

232

168

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“…Atomic absorption studies indicate that there is considerable Na+, although K+ and Ca'+ have also been identified in PVC [37,38]. The anionic species are thought to be fixed charge sites, principally sulfate, sulfonate, and carboxylate sites, that arise from impurities introduced in synthesis [ 17,37,38]. The background conductivity of the membrane is contributed by dissociation of these sites.…”

Section: Additive-membrane Interactionsmentioning

confidence: 99%

Ion pairing and acid dissociation constants in poly(vinyl chloride)‐based ion‐selective electrode membranes

Verpoorte¹,

Chan²,

Harrison³

1993

Electroanalysis

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Ion pairing and acid dissociation constants, as well as limiting conductances, have been estimated in ion-selective electrode membranes based on a 33 wt% poly(viny1 chloride) (PVC), 66 wt% dioctyladipate matrix using the Fuoss equation of conductance for weakly dissociable species. Dissociation constants of 1.66, 3.51, and 0.69 X lo-' were determined for NaC104, C6H,COOK (KBz), and benzoic acid (HBz), respectively, in a membrane matrix with 1% valinomycin and 0.01% KB(C6H,), present as additives. The first two values are consistent with tight ion pairing in a low dielectric solvent and indicate no special role for PVC in ion solvation. The weak acid dissociation is 4 to 5 orders of magnitude higher than expected; HBz also shows unusual interactions with the membrane matrix at low added concentrations. The effect of HBz and methylbenzoate (MeBz) on surface charge transfer resistance and membrane bulk resistance shows that HBz is dissociating to form ions, and a possible mechanism for the unusual interactions has been deduced. MeBz caused a significant increase in surface charge transfer resistance, indicating a mechanism by which membrane permeation by lipophilic, neutral components of biological samples could degrade sensor performance.

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“…These results clearly demonstrate that the electrical influence of fixed negative sites in membranes with mobile anionic additives cannot be neglected, even when the concentration of mobile sites is 10-100 times higher than the fixed-site content. In common plasticized PVC membranes, as used for ion-selective electrode applications, the total concentration of anionic impurities behaving as fixed sites was determined to be between 0.07 and 0.8 mmol kg À1 [25,[49][50][51][52][53]. Thus, the predicted influence of fixed sites would be observable up to around 100 mmol kg À1 of mobile sites.…”

Section: Membranes With Lipophilic Anions As Additivesmentioning

confidence: 99%

Influence of cationic and anionic additives on the electrical properties of ionophore-based ion-selective membranes

Morf¹,

Rooij²,

Pretsch³

2005

Journal of Electroanalytical Chemistry

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The steady-state electrical behavior of cation-selective ionophore membranes with different kinds of ionic additives was studied on a theoretical basis. Membranes with both mobile and fixed anionic sites exhibit nonlinear current-voltage curves, which is in contrast with the ohmic behavior of pure fixed-site membranes. This can be explained from the specific concentration profiles in the membrane, illustrating pronounced polarization effects for the mobile sites. Surprisingly, the influence of the fixed sites on the current response is still observable even when the mobile sites predominate. At high voltages, current saturation occurs by limitations of the back-diffusion of free ionophores. This can be overcome when other, uncomplexed, cations contribute to the current flow. Membranes with both cationic and anionic sites cannot be strongly polarized, in analogy to other systems where an inert electrolyte is confined to a given phase. These membranes respond with current saturation at relatively low voltages. Currents above this limit can be achieved by an additional permeation of anions from the aqueous solution through the membrane, as shown by model calculations.

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Responses of site-controlled, plasticized membrane electrodes

Cited by 182 publications

References 22 publications

Performance evaluation criteria for preparation and measurement of macro- and microfabricated ion-selective electrodes (IUPAC Technical Report)

Performance evaluation criteria for preparation and measurement of macro- and microfabricated ion-selective electrodes (IUPAC Technical Report)

Ion pairing and acid dissociation constants in poly(vinyl chloride)‐based ion‐selective electrode membranes

Influence of cationic and anionic additives on the electrical properties of ionophore-based ion-selective membranes

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