Performance of solid-membrane cation-selective electrodes for flow-injection potentiometry

✍ Scribed by L.K. Shpigun; O.V. Basanova; Yu.A. Zolotov

• Publisher: Elsevier Science
• Year: 1992
• Tongue: English
• Weight: 518 KB
• Volume: 10
• Category: Article
• ISSN: 0925-4005
• DOI: 10.1016/0925-4005(92)80005-i

✦ Synopsis

The dynamic behatiour of solid-membrane Ag, Cu, Pb and Cd ion-selective electrodes (ISEs) as detectors in a flow-injection potentiometric system is described. The predominant role of the dynamic response-time characteristics of the sensors on the potentiometric signal is emphasized. When the value of the dynamic response time r is smaller than the contact time A? of the injected primary ion solution zone with the electrode surface, a transient signal is detected and thus t dramatically affects the linear working range, the electrode response slope and the detection limit. The selectivity properties of the sensors are also dependent on the contact time and usually the potentiometric selectivity coefficients increase with increasing At. In each case, the optimal physical parameters of the flow manifold can be chosen beforehand from the dynamic response-time curves recorded with a given electrode.