A dual-signal fluorescent sensor was developed for tetracycline (TET) detection in milk with excellent reproducibility and stability. In this protocol, molybdenum disulfide quantum dots (MoS2 QDs) with blue fluorescence and cadmium telluride quantum dots (CdTe QDs) with yellow fluorescence were synthesized to establish the MoS2/CdTe-based sensor with two fluorescence emission peaks at 433 nm and 573 nm. With the addition of TET, the fluorescence of MoS2/CdTe were quenched by photoinduced electron transfer (PET), and the fluorescence of CdTe QDs were quenched more obvious than MoS2 QDs. With the strategy, a calibration curve was established between the TET concentration in the range of 0.1–1 μM and the ratio of fluorescence intensity at 573 nm and 433 nm (F573/F433). Furthermore, the dual-signal sensor was applied for TET detection in milk samples with the recovery of 95.53–104.22% and the relative standard deviation (RSD) less than 5%, indicating the strong application potential.
