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DOI

The electrochemical properties of ion-exchanger-based solvent polymeric ion-selective electrodes (ISEs)-bulk and interfacial resistance, capacitance, and polarization under a galvanostatic current step-are studied, with a nitrate ISE based on tetradecylammonium nitrate (TDANO3) as a model system. The study is performed by chronopotentiometric and impedance measurements, and focuses on the dependence of the aforementioned properties on the concentration of NO 3 -anions in solution. The impacts from the bulk and the interfacial charge transfer to the overall membrane resistance are revealed. It is shown that the bulk resistance of the membranes decreases over an increase of NO 3 -concentration within the range of a Nernstian potentiometric response of the ISE. This fact, also reported earlier for K +- and Ca 2+-selective ISEs, is not in line with current views of the mechanism of the ISE response, or of the role of ion exchange in particular. The origin of this effect is unclear. Estimates are made for the concentration of ionized species (NO 3 -and TDA +) and, respectively, for the TDANO 3association constant, as well as for the species diffusion coefficients in the membrane.

Original languageEnglish
Article number2062
Number of pages10
JournalSensors
Volume18
Issue number7
DOIs
StatePublished - Jul 2018

    Scopus subject areas

  • Analytical Chemistry
  • Atomic and Molecular Physics, and Optics
  • Biochemistry
  • Instrumentation
  • Electrical and Electronic Engineering

    Research areas

  • Bulk and interfacial resistance, Capacitance, Charged species concentrations, Chronopotentiometry, Diffusion coefficients, Electrochemical impedance, Nitrate-selective electrode, Potentiometric response

ID: 33778186