The Study Of Salicylic Acid Fluorescent Probes For Al³⁺ Detection And Cell Imaging

Objective:Aluminum has excellent physical and chemical properties,so it is widely used in production,life,industry,agriculture and so on.But it is will endanger the growth of animals and plants,and affects human health when aluninum is massive exploitation and utilization,which will lead to a series of diseases,such as Alzheimer’s disease,Parkinson’s syndrome,osteoporosis and so on.So it is of great significance to protect environment and human health form diseases caused by excessive use and intake of aluminum to study Al³⁺detection sensors fast-response,high-sensitivity and simple-to-use.Because the fluorescence analysis method has the advantages of high sensitivity,high selectivity,rapidity and simplicity,it is of great significance to explore the Al³⁺fluorescence probe with high sensitivity and high selectivity.Methods:The properties of HNA,NA,and DB probes for detecting Al³⁺,the selectivity,anti-interference ability,concentration dependence,detection limit,complex ratio,reversibility,optical stability,fluorescence lifetime and so on,were explored by UV and fluorescence spectroscopy.The recognition mechanism of Al³⁺by HNA,NA and DB was further discussed according to thermogravimetric analysis,infrared spectroscopy and nuclear magnetic resonance.Then the detection of Al³⁺in complex environment and the application of the probe in cell imaging were explored.Results:HNA,NA and DB can recognize Al³⁺in aqueous solution by fluorescence enhancement,which is not affected by other coexisting metal ions(except Fe³⁺);The fluorescence intensity is concentration dependent.（1）The HNA limit of detection for Al³⁺is 3.27×10^–9M,binding constant is1.25×10⁶;HNA can quickly identify Al³⁺in 50 s;The complex ratio of HNA to Al³⁺is 3:2.The recognition of Al³⁺by HNA is reversible and reproducible;HNA can detect Al³⁺in real samples such as tap water,campus river water,Lijiang River water,BSA,and cells.（2）The NA limit of detection for Al³⁺is 2.44×10^–9M,binding constant is9.86×10⁵;NA can quickly identify Al³⁺in 25 s and the fluorescence intensity can remain stable within 2400 s;The complex ratio of NA to Al³⁺is 3:2.The recognition of Al³⁺by NA is reversible and regenerative in the environment of adding EDTA;NA can detect Al³⁺in real samples such as BSA,cells,tap water,campus River and other water samples.（3）The DB limit of detection for Al³⁺is 9.29×10^–7M,binding constant is7.94×10⁵;DB can quickly identify Al³⁺in 150 s and the fluorescence intensity can maintained stable within 1800 s;The complex ratio of DB to Al³⁺is 1:1.The recognition of Al³⁺is reversible and regenerative in the environment of adding EDTA;DB can detect Al³⁺real samples such as BSA,cells,tap water,campus river water and other water samples.Conclusions:The fluorescent probes,small molecule salicylic acid,recognize Al³⁺with carboxyl and hydroxyl recognition groups through fluorescence enhancement effect.The main mechanism may be is the excited state intramolecular proton transfer（ESIPT）mechanism.These probes have been explored and found to have some excellent characteristics such as high sensitivity,high selectivity,green environmental protection and low toxic and side effects in the detection of Al³⁺,which can be optimized to meet the detection of Al³⁺in actual samples,and further make a convenient and fast test strip.At the same time,it can be imaged in cells and living bodies,and can be used for the detection of Al³⁺in BSA,test paper,（except HNA）cells and actual samples,It has potential practical application value.