Plasticized poly(vinyl chloride) properties and characteristics of valinomycin electrodes.  1.  High-frequency resistances and dielectric properties

Horvai, George; Graf, E.; Tóth, Klára; Püngor, E.; Buck, Richard P.

doi:10.1021/ac00126a034

Cited by 225 publications

(125 citation statements)

References 16 publications

(25 reference statements)

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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

231

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of new discoveries and experimental possibilities in the field of ISEs, some of the IUPAC recommendations have become outdated.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

231

168

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“…[17][18][19][20] Therefore, study was performed to optimize the membrane composition using membranes containing 1.8%, 2.7% and 3.7% w/w concentration of each of the three prepared ion-pairs (Fexo-R, Fexo-TPB and Fexo-TIM). The study was performed at 10 -6 M to 10 -2 M fexofenadine in a phthalate buffer solution of pH 3.5.…”

Section: Influence Of the Membrane Compositionmentioning

confidence: 99%

A Novel Membrane Sensor for Histamine H1-Receptor Antagonist “Fexofenadine”

2004

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The construction and general performance of thirteen new polymeric membrane sensors for the determination of fexofenadine hydrochloride based on its ion exchange with reineckate, tetraphenylborate and tetraiodomercurate have been studied. The effects of membrane composition, type of plasticizer, pH value of sample solution and concentration of the analyte in the sensor internal solution have been thoroughly investigated. The novel sensor based on reineckate exchanger shows a stable, potentiometric response for fexofenadine in the concentration range of 1 × 10 -2 -2.5 × 10 -6 M at 25˚C that is independent of pH in the range of 2.0 -4.5. The sensor possesses a Nernstian cationic slope of 62.3 ± 0.7 mV/concentration decade and a lower detection limit of 1.3 × 10 -6 M with a fast response time of 20 -40 s. Selectivity coefficients for a number of interfering ions and excipients relative to fexofenadine were investigated. There is negligible interference from almost all studied cations, anions, and pharmaceutical excipients, however, citrizine that has a structure homologous to that of fexofenadine was found to interfere. The determination of fexofenadine in aqueous solution shows an average recovery of 99.83% with a mean relative standard deviation (RSD) of 0.5%. Direct potentiometric determination of fexofenadine in tablets gave results that compare favorably with those obtained by standard spectrophotometric methods. Potentiometric titration of fexofenadine with phosphomolybdic acid as a titrant has been monitored with the proposed sensor as an end point indicator electrode.

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“…In addition, to experimentally confirm the validity of the Donnan failure theory, many investigators have measured potentiometric responses to primary ions with solvent polymeric membranes. Because such solvent polymeric membranes are known to contain at least an uncontrollable amount of ionic impurities, [15][16][17][18][19][20][21][22] the precise evaluation of the validity of the theory was not feasible. Only little is known, therefore, regarding the practically relevant amount of ionic sites to yield Nernstian response slopes toward primary ions with highly hydrophilic counterions, because the amount of ionic impurities in such polymeric membranes is sufficient to obtain a Nernstian slope to primary ions with hydrophilic counterions.…”

Section: Introductionmentioning

confidence: 99%

Threshold Ionic Site Concentrations Required for Nernstian Potentiometric Responses of Neutral Ionophore-Incorporated Ion-Selective Liquid Membranes

et al. 2001

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An equation that can describe the concentrations of ionic sites required for a Nernstian potentiometric response slope of neutral ionophore-incorporated ion-selective liquid membranes is presented. This equation is derived from a model based on electrical diffuse layers on both the membrane and the aqueous sides of the interface, in which the phase boundary potential is correlated to the surface charge density as well as the salt concentrations in the bulk membrane and aqueous solution. To experimentally and accurately confirm the validity of this equation, response characteristics of field effect transistors covered by neutral ionophore-based liquid membranes with varying concentrations of a derivative of tetraphenylborate as an anionic site but free of ionic impurities were examined. The observed membrane potentials and the response slopes for membranes with various concentrations of anionic sites were in good agreement with the values calculated from the theory presented in this paper with the measured complexation stability constants for the relevant systems. This result indicates that the theoretical prediction based on the proposed equation for the anionic site concentration is accessible for the preparation of neutral ionophore-incorporated ion-selective liquid membranes, which show Nernstian response slopes for the primary ions.

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Plasticized poly(vinyl chloride) properties and characteristics of valinomycin electrodes. 1. High-frequency resistances and dielectric properties

Abstract: Impedance measurements of the high-frequency bulk semicircle provide bulk resistance and geometric capacitance values of twoand three-component membranes: plasticizer, poly(vinyl chloride) (PVC), and valinomycin in combinations.

Cited by 225 publications

References 16 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)

A Novel Membrane Sensor for Histamine H1-Receptor Antagonist “Fexofenadine”

Threshold Ionic Site Concentrations Required for Nernstian Potentiometric Responses of Neutral Ionophore-Incorporated Ion-Selective Liquid Membranes

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