Devices for ion-sensing and pX measurements*
J. D. R. Thomas**
Professor Emeritus of Chemistry and Applied Chemistry,
University of Wales, Cardiff, 4 Orchard Court, Gresford, Wrexham LL12
8EB, Wales, UK
Abstract: Thirty years of ion-selective electrode (ISE) researches
at the University of Wales, Cardiff are outlined. They summarize developments
of PVC membrane ISEs, first for calcium and then of other systems, including
the improved calcium dioctyl-phenyl-phosphate sensor for calcium and
those of ion-exchangers, polyalkoxylates, and cyclic and acyclic polyethers
for various anions and cations. Electrodes based on polyalkoxylates
have interesting properties toward the polyethers themselves. Some ISE
failure causes are discussed. Attention is given to applications, including
analysis of wash liquors and nonionic surfactants, biomedical roles,
and studies of sulfate-reducing bacteria activity. Coated-wire ISEs
and ion-selective field effect transistors (ISFETs) are mentioned, as
are other modes of ISE deployment. The review concludes with some fundamental
features of PVC electrode membranes as determined by radiotracer, applied
potential, and potentiostatic approaches.
* Lectures presented at the 11th European
Conference on Analytical Chemistry (EUROANALYSIS XI), Lisbon, Portugal,
3 9 September 2000. Other presentations are published in this
issue, pp. 1-54.
**Tel: +44 (0)1978 856771; E-mail: [email protected].