A novel Cd-based MOF fluorescent sensor [(Cd)2O(BIMB)0.5(BTB)] [CUST-580, H3BTB = 1,3,5-tris(4-carboxyphenyl)benzene, BIMB = 1,4-bis((1H-imidazol-1-yl) methyl)benzene] was successfully synthesized under solvothermal conditions. Due to the unique 3D spatial structure and pores, a methyl blue@CUST-580 composite with double emission was synthesized by soaking methyl blue dye molecules. Further studies showed that CUST-580 detected the antibiotic nitrofurantoin (NFT) to the ppb level. Compared with CUST-580, methyl blue@CUST-580 exhibited higher fluorescence emission as well as sensitive fluorescence quenching activities in response to NFT with detection limits as low as 3.3 ppb. In addition, the observed fluorescence response of the composites to NFT was highly stable and reversible after the recovery experiments.
