TY - JOUR

T1 - Non-constancy of the bulk resistance of ionophore-based ion-selective electrode: A result of electrolyte co-extraction or of something else?

AU - Кондратьева, Евгения

AU - Соловьева, Елена Викторовна

AU - Хрипун, Галина Анатольевна

AU - Михельсон, Константин Николаевич

N1 - Funding Information: The authors acknowledge the support from the “Substance analysis methods” resource center c/o the St.Petersburg State University Scientific Park (Project 108-5864 ). This work was supported by the Russian Foundation for Basic Research , grant 15-03-04514 . Appendix A

PY - 2018/1/1

Y1 - 2018/1/1

N2 - The bulk resistance of ionophore-based ion-selective electrodes (ISEs) is studied by means of chronopotentiometry and electrochemical impedance using Ca 2+-ISEs with PVC membranes containing ETH 1001 as a model system. It is shown that the membrane bulk resistance is roughly the same within the range of CaCl 2 concentrations from 0.3 to 10 −3 M, and increases significantly when the concentration is decreased to 10 −4 and 10 −5 M, although the potentiometric response of the ISEs is Nernstian in all these solutions. This increase of the resistance when 10 −3 M CaCl 2 is further deleted is larger than the decrease of the resistance when CaCl 2 is replaced with Ca(SCN) 2 and Ca(ClO 4) 2. The results suggest that the non-constancy of the ISE bulk resistance is not caused by co-extraction of CaCl 2 and therefore is not in conflict with the Nernstian behavior of the IESs potentials. The effect is tentatively ascribed to the regularities of water uptake by ISE membranes.

AB - The bulk resistance of ionophore-based ion-selective electrodes (ISEs) is studied by means of chronopotentiometry and electrochemical impedance using Ca 2+-ISEs with PVC membranes containing ETH 1001 as a model system. It is shown that the membrane bulk resistance is roughly the same within the range of CaCl 2 concentrations from 0.3 to 10 −3 M, and increases significantly when the concentration is decreased to 10 −4 and 10 −5 M, although the potentiometric response of the ISEs is Nernstian in all these solutions. This increase of the resistance when 10 −3 M CaCl 2 is further deleted is larger than the decrease of the resistance when CaCl 2 is replaced with Ca(SCN) 2 and Ca(ClO 4) 2. The results suggest that the non-constancy of the ISE bulk resistance is not caused by co-extraction of CaCl 2 and therefore is not in conflict with the Nernstian behavior of the IESs potentials. The effect is tentatively ascribed to the regularities of water uptake by ISE membranes.

KW - Bulk resistance

KW - Co-extraction

KW - Ionophore-based ion-selective membranes

KW - Nernstian response

UR - http://www.scopus.com/inward/record.url?scp=85032810737&partnerID=8YFLogxK

U2 - 10.1016/j.electacta.2017.10.176

DO - 10.1016/j.electacta.2017.10.176

M3 - Article

VL - 259

SP - 458

EP - 465

JO - Electrochimica Acta

JF - Electrochimica Acta

SN - 0013-4686

ER -