Eu3+-postdoped MOFs are used for fluorescence sensing of TNP, TC and pesticides and for anti-counterfeiting ink application

Two europium-postdoped metal organic frameworks (MOFs) Eu3+@1 and Eu3+@2 [1:{[Zn2(bta)(bpy)(H2O)(2)]. 2H(2)O}n, 2:{[Ni(bta)(bpy)(H2O)(2)][Ni(bpy).(H2O)(4)].4H(2)O}n (H4bta = 1, 2, 3, 5-benzenetetracarboxylic acid, bpy = 4, 4 '-dipyridine)] were prepared by hydrothermal synthesis and post-synthesis modification. MOFs 1-2 are all three-dimensional network structure connected by (bta)4-and bpy ligands. Eu3+@1 and Eu3+@2 in aqueous solution can achieve the quantitative detection of 2, 4, 6-trinitrobenzene (TNP), tetracycline (TC) and pesticides with high sensitivity and selectivity. In particular, when the volume of TNP increases to 50 mu L, the luminescence quenching rate of Eu3+@2 can reach 99.7% and the LOD for TNP can reach 78 nM. Interestingly, Eu3+@1 has a good response to PTH (Pyrimethanil), while Eu3+@2 has a good selectivity to FLU (Fluazinam), and both can be used for rapid in-situ imaging detection of simulated pesticide residues on fresh vegetables. Under UV lamp, Eu3+@1 showed a significant fluorescence quenching effect on PTH in beans, while the fluorescence quenching effect of Eu3+@2 on FLU on cabbage was obvious. Surprisingly, two kinds of composite materials can be used as anti-counterfeiting ink functional material with strong anti-counterfeiting ability and long term stability.

Automated summary

Europium-postdoped metal organic frameworks (MOFs) can be used for quantitative detection of different compounds in aqueous solution with high sensitivity and selectivity, and can also be used as functional materials for anti-counterfeiting ink.