ISSN:
1040-0397
Keywords:
XPS analysis
;
Fluoride
;
Ion selective electrode
;
Surface analysis
;
Hydroxide interference
;
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Lanthanum fluoride and cerium fluoride single crystals, used as the sensing membranes of the fluoride ion-selective electrode (F-ISE), were investigated for their hydroxide interference and surface reactions with OH- in high pH conditions. While these membranes show fast response and excellent Nernstian behavior over a wide concertration range in buffered F- solutions, they deviate from the theoretical slope at high pH. CeF3, in particular, exhibits a much larger deviation from the Nernstian slope and a substantially slower response to a F- activity change compared to LaF3. This larger deviation is due to more extensive and faster formation of hydroxo-complexes, with the release of a greater amount of the fluoride ion into the hydrated gel layer. The slower response of the CeF3 membrane after contact with OH- is due to the formation of CeIV oxide on the surface, which acts as a blocking layer to the exchange of F-.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/elan.1140091210
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