Construction of a water-soluble fluorescent probe for copper (II) ion detection in live cells and food products

The quality of wine can be affected by excess Cu2+ due to the occurrence of oxidation reactions or precipitation. Therefore, it is essential to use simple and effective testing methods to ensure the Cu2+ content in wine. In this work, we designed and synthesized a rhodamine polymer fluorescent probe (PEG-R). The water solubility of PEG-R was improved by the introduction of polyethylene glycol, which improved the performance and broadened its application in the food field. The PEG-R was characterized by high sensitivity, selectivity and fast response to Cu2+ and was able to complete the response process within 30 s, with approximately 29-fold fluorescence enhancement of the probe after exposure to Cu2+, the limit of detection (LOD) was 1.295 × 10-6 M. The probe can be used for the determination of Cu2+ in living cells, zebrafish, white wine and food products, and it was made into practical gels and test strips.