Synthesis and application of a novel polyurethane nanoemulsion bearing coumarin derivative as a “turn-on” fluorescence sensor toward Hg2+

Abstract

A novel polyurethane (PU-co-HCCA) nanoemulsion bearing coumarin derivative (HCCA) was synthesized as a “turn-on” fluorescent probe and used to modify filter paper, and its sensing properties were investigated. Results showed that PU-co-HCCA nanoemulsion exhibited high selectivity and excellent sensitivity toward Hg2+ over other metal ions, and possessed excellent fluorescence quantum yields of 0.976, ppb-levels detection limits of 1.61 ppb and large Stokes shifts of 101 nm. Meanwhile, as an application example of as-prepared PU-co-HCCA nanoemulsion, a Hg2+ test paper was prepared by modifying filter paper with PU-co-HCCA nanoemulsion, and results indicated that the test paper is portable and convenient and has a wide working pH range. We believe that the PU-co-HCCA nanoemulsion and the modified filter paper can provide a new design principle for the application of fluorescence sensors for metal ions including Hg2+.