Flow injection amperometry as an alternative to potentiometry for solid contact ion-selective membrane-based electrodes.

Abstract

In this work we propose a flow injection amperometry at constant potential as a perspective alternative to classical potentiometry for solid contact ion-selective electrodes (SC-ISEs). The amperometric readout mode eliminates the problem of background drift and potential instability – common limitations of potentiometry for SC-ISEs. The selectivity in flowinjection and constant flow amperometric modes is similar to the potentiometric one. Moreover, flow injection amperometry in comparison to potentiometry for ion-selective electrodes provides a shorter response time, within 15–30 s, by two orders of magnitude decreased detection limit and 5-6 fold increased signal-to-noise ratio. The proposed approach is an attractive readout mode that opens new horizons for the improvement of performance characteristics of solid contact ISEs.