TY - JOUR

T1 - Electrochemical Properties of Nitrate-Selective Electrodes: The Dependence of Resistance on the Solution Concentration

AU - Михельсон, Константин Николаевич

AU - Иванова, Арина Романовна

PY - 2018/7

Y1 - 2018/7

N2 - 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.

AB - 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.

KW - Bulk and interfacial resistance

KW - Capacitance

KW - Charged species concentrations

KW - Chronopotentiometry

KW - Diffusion coefficients

KW - Electrochemical impedance

KW - Nitrate-selective electrode

KW - Potentiometric response

UR - http://www.scopus.com/inward/record.url?scp=85049163803&partnerID=8YFLogxK

U2 - 10.3390/s18072062

DO - 10.3390/s18072062

M3 - Article

VL - 18

JO - Sensors

JF - Sensors

SN - 1424-3210

IS - 7

M1 - 2062

ER -