ISSN:
1040-0397
Keywords:
Fluoride ion-selective electrode
;
Cerium fluoride
;
Neodymium fluoride
;
Samarium fluoride
;
Membrane resistance
;
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Some lanthanide fluoride (LnF3, Ln = Ce, Nd, Sm) crystals have been grown, and fluoride ion-selective electrodes (F-ISE) have been constructed using these and some commercial LaF3, single crystal membranes. Aspects of crystal growing, particularly the high-temperature dimorphism of SmF3, are addressed, and the effects on the electrode resistance and response characteristics of crystal quality, doping and membrane geometric dimensions are studied. The results show that, while doping is effective in increasing the membrane conductivity, membrane geometric dimensions also affect the electrical resistance substantially. Undoped membranes have noise-free Nernstian response to F- solutions, provided appropriate geometric dimensions are chosen. The crystal orientation of the membrane does not have noticeable effect on the performance. The crystal quality also affects the membrane resistance and performance. Single crystal membranes with minor and localized visual defects show little difference in conductivity and no difference in performance compared with a ‘perfect’ single crystal membrane. Membranes grown from lower grade starting materials do not show poorer performance although these membranes were slightly cloudy. Membranes with severe visual defects have much lower conductivity, and deteriorated performance.
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/elan.1140071004
Permalink
