A fluorescent sensor for rutin hydrate based on a cyanostilbene macrocycle

Abstract

Rutin hydrate has some pharmacological properties and is widely available in human food and household samples. Although many methods based on large-scale instruments have been established for the detection of rutin hydrate, a simple, rapid and in situ measurement strategy was rarely reported up to now. In this work, a fluorescent sensor based on the cyanostilbene macrocycle (BCM) was developed for detecting rutin hydrate with high selectivity and sensitivity. BCM is a bis-cyanostilbene macrocycle with a bridging thiourea chain prepared by “1 + 1” condensation in 75% yield. BCM possessed a good fluorescence emission at 475 nm with an absolute fluorescence quantum yield of 0.26 in DMSO–H₂O (5 : 95). It exhibited good selective detection for rutin hydrate among a series of normal ions and biomolecules with a “turn-off” fluorescence response. The binding constant of BCM for rutin hydrate was 2.4 × 10⁴ M⁻¹ and the detection limit attained 1.16 × 10⁻⁷ M. The 1 : 1 sensing mechanism was clarified using Job's plot, and ¹H NMR and MS binding spectra. The sensing ability of BCM for rutin hydrate was successfully applied in detecting rutin hydrate in a test paper, three fruits and experiments of standard addition recovery with the recoveries of 90–95%, implying the simple, rapid and in situ detecting potential of BCM for rutin hydrate in real samples and the environment.