An intrinsic dual-emitting fluorescence sensing toward tetracycline with self-calibration model based on luminescent lanthanide-functionalized metal-organic frameworks

A novel ratiometric fluorescence sensor based on lanthanide-functionalized metal-organic frameworks (Ag+/Eu3+@UiO-66(COOH)2, AEUC) with intrinsic dual-emitting bands was fabricated to determine tetracycline (TC) residues by exploiting (UiO-66-(COOH)2, UC) as reference units, Eu3+as recognition units and Ag+ as fluorescence enhancer. Benefiting from specific binding sites and functional adsorbent channels of AEUC, efficient capture and specific recognize toward TC could be achieved, remarkably enhancing the reliability. The synergistic effect of inner filter effect (IFE) and photoinduced electron transfer (PET) process between TC and AEUC was verified, enabling the detection limit and quantification limit of established strategy reaching as 12.8 nmol/L and 38.6 nmol/L and conspicuous fluorescence color gradation from red to blue. Given its portability, point-of-care sensing platform and nanoprobe-immobilized test-paper-based measurement allowing for on-site qualitative identification and semi-quantitative assay of TC was devised for sensing visualization and has been successfully applied in foodstuff samples, providing prospect in the field of smart devices for visual monitoring of TC.