| Water is the source of life.As an indispensable element for living organism,clean and safe drinking water plays a vital role in people's healthy life.Nowadays,with the rapid development of society and aggravation of environmental problems,drinking water safety becomes a society focus,and major accidents caused by it are not uncommon.Drinking water contains appropriate content of mineral salts and trace elements,which are essential to supplement human needs and maintain human health balance.Based on the fact above,it is of great significance to detect the composition and corresponding content in drinking water.Among several detection methods,fluorescence detection technology is widely accepted because of its high sensitivity,good specificity and simple testing methods.Rare earth elements have been widely used in traditional inorganic fluorescent materials and recently they have been introduced into periodic porous structures of metal-organic frameworks.Rare earth-based metal-organic frameworks possess the specific enrichment effect,structural designability and excellent fluorescence properties,they are expected to play a role in further practical applications.Metal-organic frameworks(MOFs),also known as porous coordination polymers(PCP),are crystalline frameworks with long-range ordered structures formed by metal ions or metal clusters connected by organic ligands in the form of coordination bonds.Luminescent metal-organic frameworks are one of its most important branches.In the process of material design and preparation,luminescent rare earth-based metal-organic frameworks with porous structure and good stability are synthesized by solvothermal method using rare earth ions and level-matched organic ligands containing specific Lewis sites.Based on the Lewis acid-base coordination,the interaction between MOFs host and guest analyte affects the energy transfer from the organic ligands to rare earth ions in the framework structure,and the consequently affected fluoresce intensity of rare earth ions could be used as the signal for qualitative and quantitative fluorescence detection to analytes.Iin this paper,a new type of lanthanide-based MOF Tb-MOF-1 with porous structure was synthesized by solvothermal method using organic ligand L,(3-(3,5-dicarboxylphenyl)-5-(4-carboxylphenyl)-1H-1,2,4-triazol,C17H1;N3O6).This MOF has good stability in water and luminescent performance.Further,it can be used as a phosphate radical sensor by a fluorescence quenching phenomenon with good selectivity and sensitivity(Limit of detection,LOD =11 nM).And the fluorescence quenching detection of this Tb-MOF-1 to phosphate radical was realized by thr fact that phosphate radical radical could destroy the MOF structure.Next,a luminescent MOF material Eu-MOF-2 was designed and synthesized by a solvothennal reaction of organic ligand L2(2,5-Pyridinedicarboxylic acid)and Eu(NO3)3·6H2O.This MOF is a Al3+sensor material and it has good detection specificity and sensitivity(LOD= 13 ?M).After adding Al3+into MOF suspension in water,the interaction between N atoms(Lewis base)on the ligands and Al3+ ions(Lewis acid)realized its fluorescence quenching detection of Al3+.Based on the former work,a new Europium-based MOF material Eu-MOF-3 was synthesized by solvothennal method under weak basic condition using a V-shaped organic ligand L3(4,4'-(1,3-Phenylene)dibenzoic acid).And meanwhile,a small amount of fluoride ions were added in situ to synthesize F@Eu-MOF-3,which had the same structure with Eu-MOF-3.When exposed to the Al3+ ions in water,the luminescence intensity of F'@Eu-MOF-3 strengthened obviously with the increasing Al3+concentration,which were realized through the interaction between the fluoride and aluminum ions.F-@Eu-MOF-3 showd lower LOD(1.7 ?M)and better accuracy for sensing Al3+ in water than Eu-MOF-2. |
PDF Full Text Request