Thin sensitive organic membranes on selective iron-ion sensors (original) (raw)

The organic supramolecular compound synthesized from pyrochatechoi units bound in the o~-position of a linear dicarboxylic acid (AE6) previously used as a stable chelate iron(III) in solution is applied in this work as an ionophoric reagent on ion-sensitive field-effect transistor (ISFET) and electrolyte-insulator-semiconductor (EIS) structures for iron detection. The surface gate ox!de (SiO2! sensit!zatign of sensors was performed, using three deposition methods: chemicalgraf{ingto obtain~ AE6 monolayer, deposition by vacuum sublimation of an AE6 thin fihn and incorporation in a polysiloxane gel membrane. Classical electrochemical measurements were made to test the sensitivity towards iron of the AE6 membranes, in EIS and ISFET structures. A Nernstian sensitivity, a good selectivity and a long lifetime were obtained for the evaporated layer and the gel membranes. @ 1997 Elsevier Science S.A.