Facile synthesis of highly luminescent rod-like terbium-based metal-organic frameworks for sensitive detection of olaquindox

Olaquindox (OLA), a chemically synthesized antibacterial growth promoter, despite being strictly controlled, is illegally used in feed to improve feed conversion efficiency and increase the rate of weight gain for animals. However, it has become clear that OLA has toxic effects on human beings via the transmission of OLA through the food chain. Here, by employing terbium nitrate to provide metal ions and benzene-1,3,5-tricarboxylic acid (H3BTC) as an organic ligand, a simple, rapid, and easy scale-up synthetic method was presented for the fabrication of water-stable and highly luminescent rod-like metal-organic frameworks (Tb-BTC MOFs). Using the Tb-BTC MOFs as a luminescent probe, the luminescence quenching effect was obviously observed upon the addition of OLA, ascribed to the binding of OLA molecules on the surface of Tb-BTC and the existence of an inner-filter effect (IFE) mechanism. The correlation between the luminescence quenching Delta I and the concentration of OLA was found to be linear from 1.0 to 1000.0 mu M with a detection limit of 20.6 nM. Furthermore, a Tb-BTC-loaded fiber paper was prepared and it is highly responsive (30 s) and suitable for visual OLA assay. The method described here can be successfully applied to the detection of OLA in animal feed and edible animal tissue samples.