Fluorescent probe visualization for selective detection of cuprous ion

Cuprous ion is an essential element for human life activities. However, excessive cuprous can cause dysfunction of the human body system. To help explain this evolving biology, we report a fluorescent probe for detecting unstable Cu(I). Cu(I) undergoes a metal complexation reaction with the sulfur element in the probe, resulting in a photoelectron transfer (PET) effect. The probe fluorescence is greatly suppressed, and rapid and selective visual detection of Cu(I) in the inorganic environment is realized. There is also a good linear relationship between the probe fluorescence intensity and the Cu(I) concentration (R 2  = 0.992), which can realize the quantitative detection of Cu(I). When the probe concentration is 0.1 μM, the detection limit is 15 nM, and the detection limit of the visual method is as low as 0.1 μM. This work provides a valuable starting point for real-time monitoring of the Cu(I) concentration in a human anaerobic environment based on active probes.