A conductive polypyrrole based ammonium ion selective electrode

In view of the development of miniaturized sensor arrays, a solid-contact a mmonium ion selective electrode has been investigated. A conductive polypyr role film was electrochemically deposited on a glassy carbon surface and us ed as an internal solid contact layer between the sensing membrane and soli d electrode surface. A systematic evaluation of the important parameters af fecting the electromotive force (emf) response is presented. The performanc es of this solid-contact sensor were verified using a batch-mode measuremen t setup and a wall-jet flow cell system. The designed sensor exhibited exce llent selectivity for the primary ion and a linear response over the pNH(4) (+) range 1-5 with a slope of 56.3 mV decade(-1). The sensor has a fast res ponse and is relatively robustness, and was also used to determine ammonium concentrations in natural waters, with promising results.