A dual-signal fluorescent sensor based on MoS2 and CdTe quantum dots for tetracycline detection in milk.

• A novel dual-signal fluorescent sensor was constructed for tetracycline (TET) detection. • MoS 2 quantum dots (QDs) and CdTe QDs were used to fabricate a dual-signal fluorescent sensor. • Dual-signal nanosensor significantly enhanced the reproducibility and stability. • The sensor exhibited strong application potential for TET detection in milk samples. 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 (MoS 2 QDs) with blue fluorescence and cadmium telluride quantum dots (CdTe QDs) with yellow fluorescence were synthesized to establish the MoS 2 /CdTe-based sensor with two fluorescence emission peaks at 433 nm and 573 nm. With the addition of TET, the fluorescence of MoS 2 /CdTe were quenched by photoinduced electron transfer (PET), and the fluorescence of CdTe QDs were quenched more obvious than MoS 2 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 (F 573 /F 433). 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. [ABSTRACT FROM AUTHOR]