Optical Chemosensing Performance Of Composite Nanopore Materials For Detecting Toxic And Harmful Matters

There are many pathways for hazardous substances being exposed to ecosystem.Their structures are simple,but they play a vital role and even life-threatening in the complex system.Nitrite is one of the most important pollutants in food,which has caught attention increasingly with the developing derestaurant industry.In recent years,terrorist attacks,such as suicide bombing and anthrax,often occur in the international community.As a result,the adverse impact of social and economic losses are very serious.In order to strengthen food supervision and enhance capabilities of counter-terrorism,portable sensors with rapid and accurate performance should be developed.With the development of optical fiber and optical integration technology,optical chemosensing with optical signals as the feedback information has caught people's attention increasingly for detecting ions,molecules and biomarker matters.In order to meet the requirements of practical application,research content and application prospect of optical sensing materials are expanding and deepening constantly.Combining nanoporous materials with luminescent materials can further improve sensing performance.Based on the above background,in this dissertation,novel luminescent nanoporous materials are designed with improved sensing performance for detectingnitrite,biomarker and explosive matters.This dissertation covers the magnetic,optical,and sensing features of composite materials,and discusses their possible detection mechanism.Results have been achieved as follows:1.Recyclable magnetic mesoporousnanocomposite with improved sensing performance toward nitrite In this part,a core-shell magnetic-mesoporousnanocomposite for nitrite ion detection was demonstrated,denoted as Fe3O4@Rh 6G.Rhodamine derivative acts as a recognition element to recognize nitrite;mesoporous silica serves as matrix,which can facilitate the pre-concentration of a targeted analyte,leading to superior sensitivity;Fe3O4 makes it separable through a magnet,which can facilitate the reusability for nitrite detection.Furthermore,over 95% of the original sensing signal could be recovered after six cycles.The results demonstrated that this material may be a promising candidate for nitrite ion detection in water,food,and environment.2.Ratiometric detection of an anthrax biomarker in bio-metal-organic framework A fluorescent sensor based on bio-metal-organic framework was prepared by lanthanide cations exchange,denoted as Tb/Eu@bio-MOF-1.This material can detect DPA,an unique biomarker for bacillus spores,by regulating energy transfer process.We observed visual colorimetric sensing for DPA by regulating the ratio of two different lanthanide ions.Besides,Tb/Eu@bio-MOF-1 showed nano-pore size,which benefits DPA diffusing and avoided the influence caused by other big molecules.Thus,sensitivity and selectivity of Tb/Eu@bio-MOF-1 are improved remarkably.More importantly,this porous ratiometric sensor worked equally well in human serum.3.A nanoscaled lanthanide framework as a rariocmetric fluorescence sensor for bacterial spore marker In order to further improve performance of DPA detection,nanostructured Tb/Eu(BTC)has been synthesized by introducing lanthanide into framework.The can solve the fatigue damage of the rail effectively.The lanthanide anchored bimetallic framework mainly avoids the outflow of lanthanide ions.Compared toTb/Eu@bio-MOF-1,Tb/Eu(BTC)has simple preparation process,good dispersion,low cost and ratio controlled,which improves the credibility for DPA detection.The combined merits of rapid response,low detection limit,good reproducibility,and naked-eye recognition of DPA makes Tb/Eu(BTC)a promising material for practical application.4.A Rhodamine modified MOF as a naked eye colorimetric sensor for picric acid recognition A ratiometric fluorescent sensor,denoted as RGH-Eu(BTC),for picric acid(PA)recognition was developed by covalently grafting a rhodamine probe(RGH)onto the surface of lanthanide MOFs(Eu(BTC)).In presence of acidic PA,the fluorescence of red emission was quenched by donor-acceptor electron transfer process and the green emission was aroused by spirolactam ring-opening of rhodamine.Apart from quantitatively detected PA via ratiometric fluorescence method,the RGH-Eu(BTC)sensor also exhibited qualitatively recognize PA with naked eye via colorimetric method.In addition,due to a combination of two functional moieties,this material can realize simple,rapid and accurate PA detection.