Bimetallic metal–organic frameworks-based ratiometric fluorescence sensor for the quantitative detection of thiram in fruits samples

The identification of residual thiram (Tr) in foods is vital in view of its harmful effects on human health. Herein, a ratiometric fluorescence sensor ( I 435 / I 590 ) based on rhodamine B/NH 2 -MIL-53(Al 0.75 Fe 0.25 ) was constructed for the detection of Tr. Interestingly, the probe RhB/NH 2 -MIL-53(Bim) assisted by Cu 2+ could rapidly and sensitively recognize Tr with a low detection limit of 0.11 μg/mL in 10 min. The fluorescence sensing mechanism was investigated using fluorescence spectra, UV–Vis absorption spectra, the fluorescence lifetime and quantum yield. The results showed that the excellent sensing performance was attributed to fluorescence resonance energy transfer, electrostatic interaction, and photoinduced electron transfer. In addition, the practical application of this platform showed acceptable relative recoveries for Tr (84.03–107.81 %), and precisions were also achieved (relative standard deviation ≤ 8.69 %, n = 3). These results show that the presented herein can be applied to monitor the Tr content in real fruit samples.