Synthesis and photophysical behavior of a water-soluble fluorescein-bearing polymer for Fe3+ ion sensing

An acrylic monomer bearing xanthene group, acryloylfluorescein (Ac-Flu) was synthesized from fluorescein and acryloyl chloride in the presence of triethylamine in dry dichloromethane (CH2Cl2) at room temperature. The synthesized Ac-Flu was identified by IR, MS and (HNMR)-H-1 spectra. Copolymer of Ac-Flu and acrylamide (AM) was synthesized with thermal initiator and it was characterized by the method of IR, UV-Vis and DSC. The photophysical behaviors of Ac-Flu and its copolymer were explored by recording the fluorescence spectra in solution, solid state and film in detail. In addition, the ability of the copolymer to detect different metal cations (Mn2+, Fe3+, Fe2+, Co2+, Ni2+, Cu2+, Zn2+) in aqueous solution was investigated. The results showed that poly(Ac-Flu-co-AM) had a good linear response between the logarithm of concentration of Fe3+ (lg[Fe3+]) against the relative fluorescence intensity for Fe3+ concentration. The results suggest that this copolymer may offer potential as a reusable polymer sensor for Fe3+ ion in aqueous solution.