A Rhodamine-based Dual Chemosensor for the Simultaneous Detection of Fe and Cu.

A Rhodamine-based dual chemosensor L1 for simultaneously detecting Fe and Cu was designed and synthesized. The spectroscopic properties of L1 were analyzed, and its recognition mechanism was speculated. We found that the addition of Fe induced a great fluorescence enhancement, while Cu induced a strong UV-Vis absorption enhancement. The results revealed that L1 was highly selective for recognizing Fe and Cu in UV-Vis spectroscopy in CHOH-HO (1/1, v/v, pH 7.2) with the interference of other metal ions. A good linear relationship between the fluorescence intensities of L1 and the concentration of Fe, as well as the UV-Vis absorption intensities of L1 and the concentration of Cu was observed, respectively. The detection limit was 9.2 × 10 M (5.5 μg/L) for Fe and 3.8 × 10 M (2.4 μg/L) for Cu, respectively. The detection capacity for targeted metal ions of Fe and Cu were studied, which are less than 5 min. Job's plot method for L1 with Fe and ESI-MS for L1 with Cu indicated a 1:1 stoichiometry in the complex. The results may provide an effective strategy for the design of new dual chemosensors for the rapid detection of targeted metal ions.