Design of a primary amine-selective optode membrane based on a lipophilic hexaester of calix[6]arene

Abstract

Plasticized poly(vinyl chloride)(PVC) membranes incorporating a lipophilic hexaester of calix[6]arene and a neutral H⁺-selective chromoionophore (ETH 5294) were used as reversible sensing devices for the optical determination of primary amines as exemplified by octylamine. The working range of the optode membranes is pH dependent. At pH 8.0, the absorbance response shows a good correlation with the theoretically derived equation in the measuring range from 1 × 10^–6 to 1 × 10^–3 mol dm^–3 octylamine. The selectivity, response time, reproducibility and lifetime of this optical device are discussed.