Further studies on the role of redox-active monolayer as intermediate phase of solid-state sensors

The aim of this work was to further study the impact of polyacrylate membrane and the self assembled monolayer (SAM) on the elimination Of CO2 interferences in solid-state ion-selective sensors with gold internal electrode. For this purpose permeability to CO2 of polyacrylate-based membranes has been examined. Application of differential system consisting of two W-selective electrodes differing in the composition of internal electrolyte (with and without pH-buffer system) allowed to find that CO2 is able to permeate hexanediol diacrylate (HDDA)/isodecyl acrylate (IDA)/acrylonitrile (ACN) membrane. The second goal of this work was to confirm that hydrophobic properties of applied SAMs based on ferrocene-terminated thiols mixed with n-hexanethiol is mainly responsible for the prevention of aqueous layer formation between the ion-selective membrane and the surface of inner electrode. For this purpose two types of aqueous layer tests, based on transmembrane ion fluxes as well as CO2 diffusion, were carried out. (c) 2006 Elsevier B.V. All rights reserved.