A novel ratiometric fluorescence sensor for Zn2+ detection

Abstract

A novel ratiometric fluorescent sensor for Zn²⁺, 2-(2-(2-hydroxybenzoyl)hydrazinyl)-N-(quinolin-8-yl)acetamide (F-1) with quinoline as a fluorophore and salicylhydrazide as a receptor, was designed and synthesized. F-1 shows high selectivity and sensitivity for Zn²⁺ over Cd²⁺ in a methanol–tris–HCl (0.05 M) buffer solution (1 : 9, v/v, pH = 7.0). Upon the addition of Zn²⁺, an overall 5-fold increase in the fluorescence emission ratio (I₅₀₀/I₄₂₀) was observed. An intermolecular charge transfer (ICT) mechanism is suggested for this ratiometric sensor.