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A Zn-MOF modified by silver nanoparticles (Ag@1) was synthesized by deposition reduction method. Ag@1 can serve as multi-response fluorescence sensor to detect pesticides, Trp and EDA, showing excellent sensitivity and selectivity. In particular, Ag@1 showed "turn-off" fluorescence sensing for FLU and EDA, and "turn-on" fluorescence sensing for EMB and Trp. It is also effective in detecting pesticides in simulated water and amino acids in fresh fetal bovine serum. In addition, due to its good photocatalytic activity, it can effectively degrade MB. [Display omitted] • Ag@1 was synthesized by deposition of silver nanoparticles on Zn-MOF surface. • Ag@1 showed "turn-off" fluorescence sensing for FLU and EDA. • Ag@1 showed "turn-on" fluorescence sensing for EMB and Trp. • It can effectively detect pesticides in water samples and Trp in fetal bovine serum. • Ag@1 can be used as a photocatalyst to effectively degrade the MB in water. The abuse of pesticides, antibiotics, organic solvents, etc., not only deteriorates the ecological environment, but even affects the normal development of organisms, posing a serious threat to global public health. Efficient and sensitive detection of pesticides, antibiotics, organic solvents and so on are very important, but also a challenge to scientists. By depositing Ag nanoparticles on the surface of Zn-MOF (1 : {[Zn 2 (bta)(bpy)(H 2 O) 2 ]·2H 2 O} n), a new type of composite material (Ag@ 1) was successfully synthesized and analyzed by TEM, EDS, XPS, XRD, IR and other characterization methods. Ag@ 1 can serve as multi-response fluorescence sensor to detect pesticides (fluazinam (FLU) and emamectin benzoate (EMB)), Tryptophan (Trp) and Ethylenediamine (EDA). In particular, Ag@1 showed "turn-off" fluorescence sensing for FLU and EDA, and "turn-on" fluorescence sensing for EMB and Trp. It is worth mentioning that we further explored its analysis of FLU and Trp in real water samples and fetal bovine serum. The recoveries are satisfactory, 97.95 % − 102.39 % and 96.69 % − 101.85 %, respectively. In addition, the photocatalytic performance of Ag@ 1 was found to be excellent, the degradation rate of methylene blue (MB) reached 86 %, and its degradation mechanism was discussed. [ABSTRACT FROM AUTHOR]

Two europium-postdoped metal organic frameworks (MOFs) Eu3+@1 and Eu3+@2 [ 1 :{[Zn 2 (bta)(bpy)(H 2 O) 2 ]·2H 2 O} n , 2 :{[Ni(bta)(bpy)(H 2 O) 2 ][Ni(bpy)·(H 2 O) 4 ]·4H 2 O} n (H 4 bta = 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 μL, 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. Two kinds of fluorescence sensors (Eu3+@ 1 and Eu3+@ 2) were synthesized by post-synthetic modification method. The sensor not only has high sensitivity, selectivity, stability and anti-interference ability to TNP, TC, PTH/FLU, but also can effectively detect pesticides on vegetables. It is particularly meaningful that they can be used as anti-counterfeiting ink. [Display omitted] • Two Eu-postdoped MOFs Eu3+@ 1 and Eu3+@ 2 were obtained by post-synthesis. • Eu3+@ 1 and Eu3+@ 2 sensors can achieve the quantitative detection of TNP, TC and pesticides with high sensitivity and selectivity. • Eu3+@ 1 has a good response to PTH, while Eu3+@ 2 has a good selectivity to FLU. • Eu3+@ 1 and Eu3+@ 2 have significant fluorescence quenching effect on PTH in bean and FLU in cabbage, respectively. • They can be used as anti-counterfeiting ink with strong anti-counterfeiting ability and long term stability. [ABSTRACT FROM AUTHOR]