A turn-on and reversible fluorescence sensor with high affinity to Zn2+ in aqueous solution

- A turn-on and reversible sensor could sense Zn2+ through a fluorogenic method in aqueous solutions.
- It could be recyclable with a proper reagent such as EDTA.
- The detection limit is thousand-fold lower than the WHO guideline (76 μM) in drinking water.

A new simple receptor 1 based on aminosalicylimine was prepared. It exhibited an 'off-on fluorescence type' mode with high sensitivity in the presence of Zn2+. In particular, this chemosensor could clearly distinguish Zn2+ from Cd2+. Also, it could be a reusable chemosensor because the addition of EDTA quenched the fluorescence of the Zn2+-2·1 complex. Furthermore, receptor 1 had a sufficiently low detection limit (68 nM) in aqueous solutions, which implies that 1 could sense the nanomolar concentration of Zn2+. Therefore, this sensor has the ability to be a practical system for the monitoring of Zn2+ concentrations in aqueous samples.