Europium Luminescence Used for Logic Gate and Ions Sensing with Enoxacin As the Antenna

Luminescent lanthanide ion complexes have received increasing attention because of their unique optical properties. Herein, we discovered that the luminescence of europium(III) (Eu3+) could be regulated by Ag+ and SCN- in seconds with enoxacin (ENX) as the antenna. Under given conditions, only the simultaneous introduction of Ag+ and SCN- could remarkably enhance the luminescence intensity of Eu3+-ENX complexes. This phenomenon has been exploited to design an AND logic gate and specific luminescence turn-on assays for sensitively sensing Ag+ and SCN- for the first time. Furthermore, the addition of S2- resulted in efficient luminescence quenching of the Eu3+/ENX/Ag+/SCN- system due to the strong affinity between Ag+ and S2-. Thus, a new luminescent sensing platform for S2- was established, which exhibited excellent selectivity and high sensitivity. S2- could be detected within the concentration range of 100 nM to 12.5 mu M with a detection limit of 60 nM. Such sensing system features simplicity, rapidity, and flexibility. Moreover, this proposed Eu3+-based luminescent assay could be successfully applied in the real environmental water sample analysis.