A glance into the bulk of solvent polymeric pH membranes*
Ernö Lindner1**, Robert E. Gyurcsányi1,2,
and Bradford D. Pendley3
1Joint Graduate
Program in Biomedical Engineering, The University of Memphis and University
of Tennessee Health Science Center, Herff College of Engineering, Memphis,
TN 38152-6582, USA; 2Research Group of Technical Analytical
Chemistry of the Hungarian Academy of Sciences, Department of Analytical
Chemistry, Budapest University of Technology and Economics, 1111 Budapest,
Gellért tér 4, Hungary; 3Department of Chemistry,
Rhodes College, 2000 North Parkway, Memphis, TN 38112, USA
Abstract: The pH-sensitive chromoionophores brought the dream of the
ion-selective membrane scientist close to realization. With the help
of these molecules, one can build pH-sensitive, ion-selective electrodes
and look into the bulk of solvent polymeric membranes during potentiometric
measurements (spectropotentiometry) and image concentration profiles
in situ with high spatial and temporal resolution. The combination of
electrochemical and optical information helped to interpret non-idealities
in the potentiometric responses, suppress or tailor the undesirable
transport across sensor membranes, and estimate the residual lifetime
of chronically implanted sensors. These novel opportunities provide
feedback in membrane optimizations and are expected to lead to sensor
systems with picomolar detection limits and superb selectivities.
* 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.
** Corresponding author