A fluorescent method for detection of tetracyclines (TCs) in milk was developed by using the NH2-MIL-53(Al) nanosensor synthesized via a one-pot hydrothermal method. The nanosensor had a crystalline nanoplates structure with rich groups of -NH2 and -COOH. The -NH2/-COOH of NH2-MIL-53(Al) reacted with the -CO-/-OH of TCs to form a complex. The electron of -NH2/-COOH from the NH2-BDC ligand transferred to the -CO-/-OH of TCs. -NH2 of the NH2-MIL-53(Al) interacted with the -CO-/-OH of TCs by hydrogen bonding. The quenching efficiency of the inner filter effect (IFE) was calculated to contribute 57-89%. The synergistic effect of photoinduced electron transfer (PET) and IFE account for fluorescence quenching. TCs were quantitatively detected in milk samples with recoveries of 85.15-112.13%; the results were in great accordance with high-performance liquid chromatography (HPLC) ( P > 0.05), confirming the NH2-MIL-53(Al) nanosensor has potential applicability for the detection of TCs in food matrix.
Keywords: amino-functionalized organic metal framework; fluorescence detection; inner filter effect (IFE); milk; nanosensor; tetracyclines.