Effects of α-Substituents on Ion Selectivity of Bis(12-crown-4-methyl) Malonates as Neutral Carriers for Sodium Ion-Selective Electrodes

Kimura, Kazuhiro; Yoshinaga, Masanobu; Funaki, Kaoru; Shibutani, Yasuhiko; Yakabe, Kenji; Shono, Toshiyuki; Kasai, Mitsuhiro; Mizufune, Hideya; Tanaka, Minoru

doi:10.2116/analsci.12.67

Cited by 17 publications

(11 citation statements)

References 6 publications

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“…Thus, Figure A shows the calibration curve of the nonconditioned Na + -ISE that contains NaTFPB as the ion-exchanger. This calibration curve displays a Nernstian slope of 57.05 ± 2.03 mV decade –1 and a submicromolar limit of detection of 3.24 × 10 –7 ± 0.02 M, showing a similar performance as the conditioned Na + -ISEs previously reported using a similar membrane composition . Conversely, the calibration curve of the nonconditioned Na + -ISE control membranes containing KTFPB instead of NaTFPB as the ion-exchanger (Figure B) demonstrated super-Nernstian behavior upon initial exposure to sodium ions.…”

Section: Results and Discussionsupporting

confidence: 65%

“…This calibration curve displays a Nernstian slope of 57.05 ± 2.03 mV decade −1 and a submicromolar limit of detection of 3.24 × 10 −7 ± 0.02 M, showing a similar performance as the conditioned Na + -ISEs previously reported using a similar membrane composition. 20 Conversely, the calibration curve of the nonconditioned Na + -ISE control membranes containing KTFPB instead of NaTFPB as the ion-exchanger (Figure 1B) demonstrated super-Nernstian behavior upon initial exposure to sodium ions. This is caused by a flux of sodium ions from the sample solution into the bulk of the ion-selective membrane as previously reported in the literature.…”

Section: ■ Experimental Sectionmentioning

confidence: 93%

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Circumventing Traditional Conditioning Protocols in Polymer Membrane-Based Ion-Selective Electrodes

et al. 2016

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Preparation of ISEs often requires long and complicated conditioning protocols limiting their application as tools for in field measurements. Herein, we eliminated the need for conditioning by loading the membrane cocktail with primary ion solution. This protocol significantly shortens the preparation time of ISEs yielding functional electrodes with submicromolar detection limits.The scientific research in ion-selective electrodes (ISEs) has gained momentum within the last years due to improvements in the limits of detection and selectivity, becoming now applicable for trace-level measurements by understanding transmembrane ion fluxes. 1 The response of ISEs can be described by the phase boundary potential, E PB , according the following equation:Here a I (aq) and a I (org) are the activities of primary ion (I) of charge z in aqueous and organic phases respectively, while E 0 , R, T, and F are the standard potential, gas constant, temperature and Faraday constant, respectively. When a I (org) is kept constant, the equation 1 reduces to the well-known Nernst equation:In order to render an ion-selective membrane functional, the ionophore and lipophilic ionic sites are required. One of the major roles of ionophore is to make relatively strong complexes with the primary ion, thereby establishing their constant activity in the membrane. 2 For more details see Equations SI1-SI5 in the supporting information. The role of the lipophilic ionic sites is to provide ion-exchange properties. For cation selective membrane, this process could be described by the following equilibrium:where L is a ligand (ionophore) that forms ion-ionophore complex with ion I of stoichiometry n. + − is a lipophilic ion exchanger composed of lipophilic anion R -and its counterion M + . Partitioning of I from aqueous sample into the membrane results in its exchange with M + . Anion − remains in the membrane thereby rendering the membrane permselective while preserving the charge balance. 3 In a typical experimental protocol for the preparation of ion-selective membranes the ion-exchange process is obtained by conditioning (soaking) the membrane in an aqueous solution containing the ion I (traditional protocol). 4 Significant effort in ISEs field has been spent on researching ways to miniaturize 5-9 and optimize/simplify the preparation of ISEs. [10][11][12] Reducing or eliminating the need for the conditioning step prior to the use of the electrodes is an important step for devising a simple, practical protocol for ISEs applications. 12 This would enable nontrained personnel to use ISEs quickly and reliably. In this work we propose a simple alteration of the sensor's conditioning protocol. Instead of placing the ISEs in a solution of primary ions I, solution is added directly into the membrane cocktail prior to its casting. The concentration of that solution is calculated to allow for stoichiometric exchange of I and M. Consequently, ions I are present in the membrane facilitating the formation of ion-ionophore complex according to the ...

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Section: Results and Discussionsupporting

confidence: 65%

Section: ■ Experimental Sectionmentioning

confidence: 93%

Circumventing Traditional Conditioning Protocols in Polymer Membrane-Based Ion-Selective Electrodes

et al. 2016

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“…The incorporation of geminal substituents such as long alkyl chains and benzyl groups into the alpha-position of the malonate was found to generally enhance the Na + selectivity, especially against K + , of the bis(12-crown-4) derivatives. The alpha, alpha-dibenzylmalonate derivative gave the best Na + selectivity of all the bis(crown ether)s designed here [131]. …”

Section: Application Of the Concept Of Supramolecular Chemistry In Thmentioning

confidence: 99%

Supramolecular Based Membrane Sensors

Ganjali

Norouzi

Rezapour³

et al. 2006

Sensors

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“…Usually, bis(12-crown-4) is used for sodium ions and bis(benzo-15-crown-5) is used for potassium ions. A sodium ion-selective electrode (NaISE) is composed of bis(12-crown-4) as an ionophore, a plasticizer, an anion exclusion material and PVC, and its sensitivity to sodium ions is 100 times higher than that to potassium ions [34].…”

Section: Introductionmentioning

confidence: 99%

Development of a Sensor with a Lipid/Polymer Membrane Comprising Na+ Ionophores to Evaluate the Saltiness Enhancement Effect

Nakatani

Ienaga

et al. 2019

Sensors

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The saltiness enhancement effect is the effect whereby saltiness is enhanced by adding specific substances to salt (sodium chloride). Since this effect can be used in the development of salt-reduced foods, a method to objectively evaluate the saltiness with this effect is required. A taste sensor with lipid/polymer membranes has been used to quantify the taste of food and beverages in recent years. The sensor electrodes of this taste sensor have the feature of selectively responding to each of the five basic tastes, which is realized by the lipid/polymer membranes. In this study, we developed a new saltiness sensor based on the lipid/polymer membrane with the aim of quantifying the saltiness enhancement effect. In addition to the conventional components of a lipid, plasticizer, and polymer supporting reagent, the membrane we developed comprises ionophores, which selectively capture sodium ions. As a result, the response of the sensor increased logarithmically with the activity of NaCl in measured samples, similarly to the taste response of humans. In addition, all of the sensor responses increased upon adding saltiness-enhancing substances, such as citric acid, tartaric acid and branched-chain amino acids (BCAAs), to NaCl samples. These findings suggest that it is possible to quantify the saltiness enhancement effect using a taste sensor with lipid/polymer membranes.

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Effects of α-Substituents on Ion Selectivity of Bis(12-crown-4-methyl) Malonates as Neutral Carriers for Sodium Ion-Selective Electrodes

Cited by 17 publications

References 6 publications

Circumventing Traditional Conditioning Protocols in Polymer Membrane-Based Ion-Selective Electrodes

Circumventing Traditional Conditioning Protocols in Polymer Membrane-Based Ion-Selective Electrodes

Supramolecular Based Membrane Sensors

Development of a Sensor with a Lipid/Polymer Membrane Comprising Na+ Ionophores to Evaluate the Saltiness Enhancement Effect

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