A turn-off fluorescent chemical sensor based on a thiazole-Schiff base structure for highly selective and accurate detection of Cu2+ in living cells†

Abstract

A Schiff base fluorescent probe, HTT, based on a sulfonylhydrazone structure was designed and synthesized for the sensitive and selective detection of Cu²⁺. The probe HTT exhibits good anti-interference performance toward Cu²⁺ in the presence of a variety of metal ions. After the addition of Cu²⁺, it can quickly respond within 40 seconds, and the fluorescence detection limit is 1.10 nM. The coordination ratio of probe HTT and Cu²⁺ is 2 : 1, and the coordination reaction between CN, SO and Cu²⁺ limits the formation of hydrogen bonds between the hydroxyl group and CN, disrupting the spatial coplanar effect of the probe molecule and thereby inducing fluorescence quenching. The probes can be recovered and reused using EDTA for the detection of Cu²⁺. The probe was also applied to the successful monitoring of Cu²⁺ in living cells and real water samples.