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Hydrophobic Membranes as Liquid Junction‐Free Reference Electrodes
Author(s) -
Bakker Eric
Publication year - 1999
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/(sici)1521-4109(199907)11:10/11<788::aid-elan788>3.0.co;2-4
Subject(s) - membrane , potentiometric titration , electrode , electrolyte , materials science , analyte , lipophilicity , reference electrode , inert , biosensor , nanotechnology , ionic liquid , chemical engineering , chemistry , chromatography , organic chemistry , biochemistry , engineering , catalysis
This article critically compares four recently proposed chemical designs to develop miniaturizable reference electrodes on the basis of hydrophobic membrane materials. The use of such materials would be highly promising to develop potentiometric sensor arrays for the assessment of a multitude of ionic analytes since manufacturing the reference electrode would not be substantially different from the actual sensing electrodes. Results and possible pitfalls in the proposed design schemes are discussed. It is shown that the use of an anion and cation responsive membrane, connected in parallel, will only function under extremely well‐defined conditions. The use of essentially nonresponsive polyurethane materials has shown considerable worth, but the results could currently also be explained with a porous membrane that acts as a liquid junction. Using inert electrolytes in the membrane with well‐tuned lipophilicity, on the other hand, shows usefulness but requires very careful experimental and theoretical characterization. Polyion responsive membranes are an additional, very different approach to developing reference electrodes, especially in view of an application in whole blood samples.