Development and characterization of a copper ion-selective optical sensor based on a novel calix[4]dicyano-diimidazole thin film

A novel optical sensor for sensitive and selective determination of copper ions in aqueous solution based on a novel calix[4]dicyano-diimidazole ionophore was prepared. The newly synthesized calix[4]dicyano-diimidazole exhibited obvious absorbance enhancement at 284 nm in the presence of copper ions. At pH 6.8, the measuring range of the optode membrane for Cu2+ ions was from 1.0 × 10−8 to 1.0 × 10−4 M with a detection limit of 7.0 × 10−9 M. Furthermore, the response time of the proposed optical device was within 10 min. With the optimum condition described, the optical sensor revealed good selectivity toward Cu2+ ions in comparison with common coexisting cations (Hg2+, Pb2+, Cd2+, Ni2+ and Zn2+). Finally, the reproducibility, regeneration, reversibility and repeatability of this optical sensor were discussed.