A novel fluorescent probe for copper (II) ion based on rare earth polyoxometalate

A new strategy for the determination of Cu(II) ions was developed using K10H3[Eu(SiMo6W5O39)(2)]center dot 28H(2)O. The polyoxometalate H4SiMo6W6O40 acts as a ligand to sensitize the europium ion to emit red fluorescence, and the fluorescence was quenched by the addition of Cu(II) ions. The luminescence of the central Eu3+ was quenched due to the inner filter effect (IFE) of Cu(II) to K10H3[Eu(SiMo6W5O39)(2)]center dot 28H(2)O and the static burst. Therefore, K10H3[Eu(SiMo6W5O39)(2)]center dot 28H(2)O can be used as a specific fluorescent probe for Cu2+ and it exhibited a very good linear response range for copper ions from 1 to 20 mu M with detection limit of 0.13 mu M. The probe was successfully applied to the determination of Cu(II) ions in clam samples with recoveries in the range of 90-98%.