Development of a Micro-Potentiometric Sensor for the Microchip Analysis of Alkali Ions

Abstract

This paper reports on the development of a micro-potentiometric sensor based on external microelectrodes introduced into a microchip. We miniaturized reference and ion-selective electrodes (ISEs) and embedded them into a plastic (PDMS) microchip; the miniaturization of ISE was attained by using a monolithic capillary-based membrane. This sensor was applied to the detection of alkali ions (Na⁺, K⁺ and NH₄⁺) in a microflow on the μg/L level.