The water uptake of plasticized poly(vinyl chloride) solid-contact calcium-selective electrodes

A1 Journal article (refereed)


Internal Authors/Editors


Publication Details

List of Authors: Tom Lindfors, Fredrik Sundfors, Lajos Höfler, Róbert E. Gyurcsányi
Publisher: WILEY-BLACKWELL
Publication year: 2011
Journal: Electroanalysis
Journal acronym: ELECTROANAL
Volume number: 23
Issue number: 9
Start page: 2156
End page: 2163
Number of pages: 8
ISSN: 1040-0397
eISSN: 1521-4109


Abstract

A hyphenated method based on FTIR-ATR and electrochemical impedance spectroscopy has been applied to simultaneously measure the water uptake, changes in the bulk resistance and potential of plasticized poly(vinyl chloride) (PVC) based Ca(2+)-selective coated-wire (CaCWE) and solid-contact electrodes (CaSCISEs). Most of the water uptake of the ion-selective membranes (ISMs) used in both electrode types took place within the first 9 h in 10(-3) M CaCl(2) showing good correlation with the stabilization of the individual electrode potentials. The bulk resistance of the ISMs of the CaCWEs and the CaSCISEs with poly(3-octylthiophene) (POT) as the solid-contact (SC) increased most during the first 18 h in 10(-3) M CaCl(2). The increase in the resistance was found to be related to the exchange of K+ for Ca(2+) in the ISM and the formation of the Ca(2+)-ionophore (ETH 5234) complex having a lower diffusivity than the free K(+) ions. In contrary to previously published results on silicone rubber based SCISEs and poly(methyl methacrylate): poly(n-decyl methacrylate) membranes containing POT, the plasticized PVC-based CaSCISEs with POT as the SC had a higher water uptake than the CaCWEs. The CaSCISEs had a detection limit of 2 x 10(-8) M Ca(2+) and a good potential reproducibility of 148.9 +/- 1.0 mV in 10(-4) M CaCl(2).


Keywords

Electrochemical impedance spectroscopy, FTIR-ATR spectroscopy, Plasticized poly(vinyl chloride), Poly(3-octylthiophene), Potential stability, Solid-contact ion-selective electrode, Water uptake

Last updated on 2019-23-09 at 02:42