A Eu(III) doped metal-organic framework conjugated with fluorescein-labeled single-stranded DNA for detection of Cu(II) and sulfide.

In this paper, Bio-MOF-1 is prepared as reported and then Eu is introduced into it via cation exchange method. A FAM-labeled ssDNA is chosen to fabricate with the obtained Eu@Bio-MOF-1. A luminescent hybrid material is assembled, which can exhibit the fluorescence of Eu and FAM simultaneously by adjusting the ratio of FAM-ssDNA and Eu@Bio-MOF-1. The sample is then used for the detecting of metal ions, results shows which has good selectively for Cu (LOD = 0.14 μM, 0-250 μM). The introduction of Cu can quench the fluorescence of FAM while the luminescent intensity of Eu enhancing. After the detection of Cu, the Cu involved hybrid system can then be further employed for the detection of S (LOD = 1.3 μM, 0-50 μM). Low concentration of S can make the luminescent intensity of Eu decrease gradually while high concentration of S can further recover the luminescent of FAM, which is quenched by Cu.