Fast visualization of multiple trace antibiotics by modified Eu/Tb MOF test paper

To address the current situation of the poor detection efficiency of multiple trace antibiotic contamination in the aqueous environment, we synthesized a modified lanthanide MOF material, Ln-MOF(NH₂)@R6G, for the rapid visual quantitation of trace norfloxacin (NOR), ciprofloxacin (CIP) and tetracycline (TC). By introducing the ligands of NH₂-BDC and R6G with abundant amino groups, the interaction of material with antibiotics was largely strengthened. Sensitive detection completed within 1 min with dramatically low detection limit of LOD_NOR = 16.56 nM, LOD_CIP = 6.14 nM, LOD_TC = 19.6 nM. Based on the visible color change to the naked eyes, we succeeded in loading the synthesized material onto the test paper, which realized semi-quantitative detection of antibiotics (concentration range of 10-100 μM) in actual water systems. Taking advantages of the significant difference of the NOR and CIP induced fluorescence color, as well as the non-interfering property with each other, we developed a data model for simultaneously visual quantifying NOR and CIP by the RGB-CIE variation maps in their coexisting actual system (recoveries 96.48 %-105.34 %, RSD 0.03 %-0.81 %). The result developed a promising portable visual analysis for the trace antibiotics in complex waters, and provided a novel strategy for in situ screening of environmental pollutants.