A simple fluorescent probe for Cd2+ in aqueous solution with high selectivity and sensitivity.

A simple quinoline-based fluorescent probe, PBQ, which contained a tweezer-like receptor, was successfully developed via one-step synthesis. PBQ exhibited a 40-fold fluorescence enhancement response to Cd2+ in aqueous solution. PBQ was found to have excellent selectivity for Cd2+ over many other metal ions (Ba2+, Mn2+, Hg2+, Ni2+, Ca2+, Cu2+, Co2+, Pb2+, Mg2+, Zn2+, Fe2+, Fe3+, Cr3+, Ag+, Li+, Na+, K+). Significantly, its fluorescence intensity was enhanced in a linear fashion with the concentration of Cd2+. Thus PBQ can be potentially used for the quantification of Cd2+. Moreover, a series of model compounds were rationally designed and synthesized in order to explore the binding mode of PBQ with Cd2+.