Zr(H2O)(2)EDTA modulated luminescent carbon dots as fluorescent probes for fluoride detection

A novel fluorescent probe (Zr(CDs-COO)(2)EDTA) has been designed for fluoride ion (F-) content detection based on the competitive ligand reactions carried out between the carboxylate groups (-COOH) on the surface of the luminescent carbon dots (CDs) and F- coordinated to Zr(H2O)(2)EDTA. The strong and stable fluorescence signal of this probe was quenched upon the addition of F- as a result of the formation of the non-fluorescent complex Zr(F)(2)EDTA, due to the stronger affinity of F- than the -COOH in the CDs to Zr(IV). The fluorescence change (Delta F) in this process was linear with respect to the content of F-, ranging from 0.10 mu M to 10 mu M. The probe has been applied to F- detection in toothpaste and water samples with satisfactory results. Moreover, the mechanism of this Zr(H2O)(2)EDTA modulated fluorescent probe for the detection of F- was also discussed.