Amino-Functionalized Al–MOF for Fluorescent Detection of Tetracyclines in Milk

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.