A series of novel water soluble quinoline derivatives 1a∼1d were synthesized from 8-hydroxyquinoline and the fluorescence of these compouds had been quenched by Cu2+ or Fe3+ in absolute water. It was seen that the fluorescence of 1a was quenched by 93% with addition of 50 μM of Cu2+ in absolute water and 75% in the presence of 50 μM of Fe3+ with the quenching ratio (Cu2+ :Fe3+) of 1:0.80, showing much higher sensitivity and selectivity of Cu2+ to Fe3+. In addition, the presence of some other metal ions such as K+, Ca2+, Zn2+, Al3+, Mn2+, Fe2...
