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

Abstract

A novel fluorescent probe (Zr(CDs–COO)₂EDTA) 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)₂EDTA. 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)₂EDTA, due to the stronger affinity of F⁻ than the –COOH in the CDs to Zr(IV). The fluorescence change (ΔF) in this process was linear with respect to the content of F⁻, ranging from 0.10 μM to 10 μM. The probe has been applied to F⁻ detection in toothpaste and water samples with satisfactory results. Moreover, the mechanism of this Zr(H₂O)₂EDTA modulated fluorescent probe for the detection of F⁻ was also discussed.