Facile fluorescent probe for simultaneous fluorescence detection of fluoroquinolones and copper

A facile fluorescent probe (FFP) based on single-excitation/dual-emission detection system for the simultaneous sensing of fluoroquinolones (FQs) and copper was prepared via sol–gel polymerization using graphene carbon dots (GCDs) and CdTe quantum dots (CdTe QDs) as fluorescent units. FQs were detected by GCDs fluorescence enhancement, and copper (II) [Cu(II)] was detected by fluorescence quenching of the CdTe QDs in the FFP. If only one FQ co-existed with Cu(II), simultaneous quantitative analysis could be performed. The norfloxacin (NOR) was used as an example to investigate the working conditions of FFP. Under optimal conditions, the FFP could linearly recognize NOR with its concentration over the range 0–50 µM, with a detection limit of 1.6 nM. Meantime, the FFP could linearly detect the concentration of copper over the range of 0–10 µM, with a detection limit of 48.4 nM. NOR and Cu(II) were then detected simultaneously in tap water, drinking water, seawater, and milk with good recoveries. When multiple FQs co-existed with Cu(II), the FFP could discriminate among four different FQs via linear discriminant analysis. Therefore, this facile fluorescent probe can be used for simultaneous detection of various types of compounds in liquid samples.