pH-ISEs with an expanded measuring range based on calix[4]arenes: specificfeatures of the behaviour and description of the electrode response

Citation
Vv. Egorov et Yv. Sin'Kevich, pH-ISEs with an expanded measuring range based on calix[4]arenes: specificfeatures of the behaviour and description of the electrode response, TALANTA, 48(1), 1999, pp. 23-38
Citations number
50
Categorie Soggetti
Spectroscopy /Instrumentation/Analytical Sciences
Journal title
TALANTA
ISSN journal
00399140 → ACNP
Volume
48
Issue
1
Year of publication
1999
Pages
23 - 38
Database
ISI
SICI code
0039-9140(199901)48:1<23:PWAEMR>2.0.ZU;2-Y
Abstract
This article contains a description of pH-ISEs with plasticised PVC membran es that contain calix[4]arene or p-tertbutylcalix[4]arene as an ionophore a nd tetradecylammonum nitrate taken in a subequivalent amount relative to ca lyxarene as an ionic additive. It has been discovered that real ISEs have a n extraordinarily wide measuring range which is about 1.5-2 pH units wider then the measuring range of tridecylamine-based ISEs under the same conditi ons. Just as in the case of amine-type neutral carriers-based pH-ISEs, the upper detection limit depends on the concentration and lipophilicity of ani ons and the lower limit, on the concentration and lipophilicity of cations present in the sample solution. A simple quantitative description of the el ectrode response and the detection limits of such ISEs is suggested which i s based on inclusion of extraction equilibria at the membrane/solution inte rface for two limiting cases: complete dissociation and strong association of ions in the membrane. Interface equilibria constants that occur in the a cid and alkali media are estimated experimentally in model extraction syste ms. Characteristics of the ISEs calculated with use of the estimated consta nts agree satisfactorily with those measured experimentally. Probable reaso ns of the expansion of the measuring range of the ISEs considered in compar ison with ISEs based on amine-type neutral carriers are discussed. (C) 1999 Elsevier Science B.V. All rights reserved.