Potential reproducibility of potassium-selective electrodes having perfluorinated alkanoate side-chain functionalized poly(3,4-ethylenedioxytiophene) as hydrophobic solid contact

A1 Journal article (refereed)


Internal Authors/Editors


Publication Details

List of Authors: Soma Papp, Márton Bojtár, Róbert E. Gyurcsányi, Tom Lindfors
Publisher: American Chemical Society
Publication year: 2019
Journal: Analytical Chemistry
Journal acronym: Anal. Chem.
Volume number: 91
Start page: 9111
End page: 9118


Abstract



ABSTRACT: The irreproducibility of the standard potential (E0) is probably the last
major challenge for the commercialization of solid-contact ion-selective
electrodes (SCISEs) as single use or wearable sensors. To overcome this issue,
we are introducing for the first time a perfluorinated alkanoate side-chain
functionalized poly(3,4-ethylenedioxythiophene) (PEDOTF) as a hydrophobic SC in
potassium-selective electrodes (K-SCISEs) based on plasticized poly(vinyl
chloride). The SC incorporates the tetrakis(pentafluorophenyl)borate (TFAB-)
anion, which is also present as a lipophilic additive in the ion-selective
membrane (ISM), thus ensuring thermodynamic reversibility at the SC/ISM
interface and improving the potential reproducibility of the electrodes. We
show here that the PEDOTF-TFAB solid contact, which was pre-polarized prior to
the ISM deposition either to its half- or fully conducting form (i.e. different oxidation states) in
acetonitrile containing 0.01 M KTFAB, had a very stable open-circuit potential
and an outstanding potential reproducibility of only ±0.5 mV (n=6) for 1 h in
the same solution after the pre-polarization. This shows that the oxidation
state of the highly hydrophobic PEDOTF-TFAB film (water contact angle 133°) is stable over time and can be precisely controlled with
pre-polarization. The SC was not either light sensitive that is normally a
disadvantage of conducting polymer SCs. After the ISM deposition, the standard
deviation of the E0 of the
K-SCISEs prepared on glassy carbon was ±3.0 mV (n=5), which is the
same as for conventional liquid contact K-ISEs. It indicates that the ISM
deposition is the main source for the potential irreproducibility of the
K-SCISEs, which has been overlooked previously.




Keywords

Chemical sensor, Electrically conducting polymer, Ion-to-electron transducer, Solid-contact ion-selective electrodes


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Last updated on 2019-22-10 at 04:56