In this work, a novel fluorescent chemosensor combining multiple photoinduced electron transfer（PET） processes for the detection ofAg＋ ion was synthesized. The PET processes were derived from the lone electron pair of the selenium donors and the tertiary nitrogen atom of the coumarin fluorophore, which have not yet been used in the fluorescent chemosensor designed for Ag＋ ion. Interestingly, the chemosensors showed fluorescent responses to Ag＋ ion with a fluorescence enhancement factor of 3--5-fold by blocking the intramolecular PET quenching path- ways. Furthermore, the probe exhibited high selectivity and sensitivity for Ag＋ ion over other relevant species with detection limit down to 10 nmol/L level. The chemosensors also showed excellent performances in analyzing natural water samples. The chemosensors developed herein represent a new strategy for the PET fluorescent chemosensor design for the detection ofAg＋ ion.
