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Electrochemical characterization of aminated PVC‐based ion‐selective membranes
Author(s) -
Cosofret Vasile V.,
Lindner Ernö,
Buck Richard P.,
Kusy Robert P.,
Whitley John Q.
Publication year - 1993
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/elan.1140050904
Subject(s) - potentiometric titration , membrane , chemistry , electroanalytical method , piperazine , ion selective electrode , electrochemistry , electrical impedance , ion , dielectric spectroscopy , characterization (materials science) , analytical chemistry (journal) , inorganic chemistry , chromatography , chemical engineering , electrode , materials science , selectivity , organic chemistry , nanotechnology , biochemistry , electrical engineering , catalysis , engineering
The potentiometric and impedance characteristics of a large number of pH sensitive, piperazine‐based aminated PVC membranes are summarized. The main goal of the work was to predict the differences between “good” and “bad” responsive potentiometric pH membranes with very similar overall nitrogen contents. The only conclusion gained previously from other methods was that the N content should be between 0.5 and 0.8% for Nernstian response. The detailed analysis of the data show that a given N content of the basic material is a necessary but not a sufficient requirement with respect of the quality of potentiometric response. Conditions for appropriate pH response of the membrane are formulated in terms of surface and bulk impedance characteristics. The ideal pH response of an optimized aminated PVC membrane, which corresponds to a minimum surface impedance, is presented. The primary importance of surface amines relative to bulk amines (the conformation and distribution of active sites) is proven in a simple experiment.