Design,Synthesis And Imaging Of Fluorescent Probes For Detection Of Formaldehyde And Hydrazine

Fluorescent probes are compounds based on molecular recognition that interact with analytes to cause changes in fluorescence properties.Combined with fluorescent imaging technology,fluorescent probes has been widely used in environmental monitoring,analytical chemistry,pharmaceutical chemistry,medical diagnosis,biochemistry and cell biology because of its high selectivity,sensitivity and ease of operation.Formaldehyde（FA）is the simplest aldehyde and an active carbonyl substance（RCS）.Formaldehyde has long been considered as a carcinogen.The increase of FA is related to various diseases,including various cancers,neurodegenerative diseases and diabetes.Therefore,the development of fluorescent probes for detection FA is of great significance for understanding physiological and pathological processes.In the second chapter of this paper,fluorescent probes FATP-1～FATP-5 were designed and synthesized based on quinoline ring structure.The optimal probe FATP-1 was selected through in the vitro testing.FATP-1 has high selectivity、sensitivity（LOD=0.3μM）and excellent two-photon excitation properties,after reaction with FA,fluorescence intensity increased by 6.4 times,Two-photon imaging experiments were carried out on cells and C.elegans.,respectively,proving that FATP-1 has the ability to detect endogenous and exogenous FA.In the animal in vivo experiment,the abnormal increase of FA was successfully detected in the brain of epileptic mice,which successfully proved that FATP-1 can be used as a tool to detect FA in the brain of living animals.This research further reveals the association between the abnormally elevated endogenous FA and epilepsy,and gives crucial information for the prevention and treatment of FA-related neurodegenerative disease.Hydrazine hydrate（NH₂NH₂,Hydrazine）is a well-known high-energy propellant.Its reductibility and alkalinity make it popular in many applications including rocket propulsion systems,chemical and pharmaceutical systems.At the same time,NH₂NH₂is also a toxic substance and has severe mutagenic effects causing serious damage to the liver,lungs,kidneys and human central nervous system.Therefore,the development of fluorescent probes for specific detection of NH₂NH₂is of great significance to industry and production.In the third chapter of this paper,based on the ESIPT mechanism,we used the benzothiazole structure as the fluorescent nucleus,and the fluorescent probes QYL-1～QYL-3 were designed and synthesized.Through ultraviolet spectrum and fluorescence spectrum screening,we found that QYL-1 has high selectivity and sensitivity（LOD=0.12μM）,and it increases linearly in the range of 0-200μM,which fully meets the U.S.Environmental Protection Agency（EPA）regulations for NH₂NH₂carcinogenicity（10 ppb）.Through testing water samples、cell and Arabidopsis root fluorescence imaging experiments,we connected the upstream and downstream nodes of hydrazine to fulfilled the closed-loop demonstration.this work shows that QYL-1 can be used to detect important nodes in the cycle and offered initial information for the closed-loop monitoring of hydrazine circulation.