Hyphenated FT-IR-attenuated total reflection and electrochemical impedance spectroscopy technique to study the water uptake and potential stability of polymeric solid-contact ion-selective electrodes

A1 Journal article (refereed)

Internal Authors/Editors

Publication Details

List of Authors: Tom Lindfors, Lajos Höfler, Gyula Jágerszki, Róbert E. Gyurcsányi
Publication year: 2011
Journal: Analytical Chemistry
Journal acronym: ANAL CHEM
Volume number: 83
Issue number: 12
Start page: 4902
End page: 4908
Number of pages: 7
ISSN: 0003-2700
eISSN: 1520-6882


A new hyphenated method utilizing FT-IR-attenuated total reflection (ATR) and electrochemical impedance spectroscopy (EIS) is presented to correlate the water uptake with concomitant potential and impedance changes of polymeric coated-wire electrodes (CWEs) and solid-contact ion-selective electrodes (SCISEs). The Ca(2+)-selective silicone rubber (RTV 3140) based SCISEs with poly(3-octylthiophene) (POT) as the solid-contact (SC) showed good correlation between a very low water content at the Pt-coated ZnSe substrate/SC interface and a superior potential stability. This is due to the hydrophobicity of both RTV 3140 and POT and the approximately 2 orders of magnitude lower water diffusion Coefficients in POT compared to RTV 3140. Practically no potential drift could be observed during 24 h when unconditioned CaSCISEs were contacted with 10(-3) M CaCl(2), in contrast to the Ca(2+)-selective CWEs with considerably higher water uptake and potential drift. The CaSCISEs had a fast Nernstian response with a detection limit of 8 x 10(-9) M Ca(2+) and a good reproducibility and stability of the standard potential, which indicates that the CaSCISEs does not require any conditioning prior to use.

Last updated on 2020-28-05 at 06:01