title: Paper-based ion-selective potentiometric sensors.
abstract: A new approach to develop ultra low-cost, robust, rugged, and disposable potentiometric sensors is presented. A suspension of carbon nanotubes in a water-surfactant mixture (carbon nanotubes ink) is applied on conventional filter papers to turn them into conductive papers, which are then used as a substrate to build ion-selective electrodes. The electrodes are made by drop casting a membrane on a small circular area of the conductive paper. In this way, the carbon nanotubes act as both electric conductors and ion-to-electron transducers of the potentiometric signal. Electrodes for sensing K(+), NH(4)(+), and pH were built and tested using this approach, and the results were compared with classical solid-state ion selective electrodes using carbon nanotubes as transducers and glassy carbon as a substrate. In all cases, the analytical performance (sensitivity, linear ranges, limits of detection, selectivity, etc.) of these disposable paper electrodes was similar to that obtained for the more conventional type of ion-selective-electrodes. This opens new avenues for very low-cost platforms for generation of chemical information.
authors.affiliation: Department of Analytical and Organic Chemistry, Universitat Rovira i Virgili, 43007 Tarragona, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Novell
authors.forename: Marc
authors.initials: M
authors.lastname: Parrilla
authors.forename: Gastón A
authors.initials: GA
authors.lastname: Crespo
authors.forename: F Xavier
authors.initials: FX
authors.lastname: Rius
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Andrade