Two near-infrared fluorescent probes based on dicyanoisfluorone for rapid monitoring of Znand Pb.

Zinc (Zn) and lead (Pb) ions in the environment have important effects on human health and environmental safety. Therefore, it is necessary to effectively detect them by a convenient and reliable analysis method. In this study, two near-infrared fluorescent probes for the fast determination of Znand Pbwere synthesized by a simple Schiff base reaction between the dicyanoisophorone skeleton and carbohydrazide derivatives. Among them, the probe with the thiophene-2-carbohydrazide group showed a selective fluorescence response to Znand Pbwith a maximum emission wavelength of 670 nm. And the detection limits of the probe for Znand Pbwere 1.59 nM and 1.65 nM, respectively. In contrast the probe modified by the furan-2-carbohydrazide group achieved quantitative detection of Zn, with a detection limit of 2.7 nM. These results were attributed to the fact that the probes bind to Znand Pbin stoichiometric ratios of 1:1, blocking the intramolecular PET effect. Furthermore, these two probes can be recycled through the action of EDTA and have been successfully used to detect Znand Pbin real water samples.