Coumarin Xanthene Combined Probe for the Multi-Color Detection of Metal Ions and Electrospun Fibers Developed for Real-Time Monitoring.

Abstract

A coumarin-rhodamine (RhBC)-fused colorimetric/fluorescent probe was designed and synthesized. The probe is effective in Cu2+/Hg2+ ion sensing. With the added Cu2+ to RhBC in water: N, N-dimethyl formamide (8:2, v/v), the cyclic form of RhBC, is converted into the open ring form and shows a clear color change from yellow to red. In the presence of additional participating cations, this moiety shows effectiveness for Cu2+ and Hg2+ ions. The RhBC's detection limit by the UV-visible spectral method was 8.81 × 10-6M for Cu2+ ions and 2.26 × 10-5M for Hg2+ ions. The detection limit in the fluorescence titration spectra was 2.02 × 10-7M for Cu2+ ions and 6.11 × 10-8M for Hg2+ ions. A 1:1 stoichiometric ratio was validated between the probe and copper/mercury ions by the method of the job plot. Moreover, RhBC-combined polyurethane electrospun nanofibers were synthesized. These nanofibers could detect Cu2+ in real samples with no complications, with an instinctive color difference from yellow to red and a weak orange color for mercury ions.