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Potential Drifts of Solid‐Contacted Ion‐Selective Electrodes Due to Zero‐Current Ion Fluxes Through the Sensor Membrane
Author(s) -
Fibbioli Monia,
Morf Werner E.,
Badertscher Martin,
de Rooij Nicolaas F.,
Pretsch Ernö
Publication year - 2000
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/1521-4109(200011)12:16<1286::aid-elan1286>3.0.co;2-q
Subject(s) - electrode , ion , monolayer , membrane , aqueous solution , analytical chemistry (journal) , materials science , layer (electronics) , chemistry , nanotechnology , chromatography , organic chemistry , biochemistry
A thin aqueous layer is formed between the polymeric ion‐selective membrane and an inner gold electrode. Its composition can be altered upon sample changes, which leads to drifting potentials. It is shown by theory and experiment that interfering ions enter the inner layer much faster than primary ones. Measurement protocols with equal contact times for the sample and the reconditioning solution can therefore not eliminate the effect of changes in the composition of the inner solution. The formation of an inner aqueous film and corresponding drifts for solid‐contacted membrane electrodes can be avoided by creating a lipophilic self‐assembled monolayer on the surface of the inner electrode.