Anion-sensitive field-effect transistors based on sol–gel-derived membranes incorporating quaternary ammonium salts

Abstract

Quaternary alkylammonium chlorides were encapsulated or bonded covalently to sol–gel-derived membranes made of mixtures of two alkoxysilanes so as to obtain sensing membranes for anion-sensitive field-effect transistors. Both types of anion sensors responded to chloride-ion activity changes with high sensitivity. The anion-sensing membranes modified chemically by an alkoxysilyl derivative of quaternary ammonium salt are superior to those simply encapsulating an ammonium salt in their durability and protein-adsorption properties. The anion sensors are applicable to chloride-ion assay in serum samples.