Design,Synthesis And Characterization Of Rhodamine-based Copper Ion Fluorescent Probes

Heavy metal ions are closely related to human survival.Heavy metals tend to accumulate in the food chain and are difficult to degrade.Excessive intake not only affects the health of organisms,but also destroys the ecosystem on which we live.In recent years,it has been regarded as the main guiding factor causing biosphere pollution and many diseases.As a member of heavy metal ions,copper is an important element widely used in scientific research and production in metallurgy,geology,chemical industries,and materials science.It is also one of the important trace elements that the human body participates in physiological and pathological events.The lack of copper in the human body can affect the activity of enzymes and inhibit cell metabolism,leading to arterial disease,high cholesterol and coronary heart disease.In addition,excessive intake of copper will increase the burden on the liver,leading to liver ascites,cirrhosis and other diseases.Water pollution based on the current heavy metals has gradually become a global problem,which not only affects the human body’s metabolic function and health,but even harms the natural environment,causing huge losses in property and species diversity.Therefore,it is important to design and develop a method for detecting Cu²⁺with high sensitivity and high selectivity.With high sensitivity,low consumption,simple operation,high selection and many other excellent properties of fluorescent probe technology,it has gradually been widely used.In recent years,a series of probes that can be used for Cu²⁺detection have been reported in succession at home and abroad.However,designing and synthesizing a Cu²⁺detection probe suitable for complex water environment still faces severe challenges.In view of the unique fluorescence characteristics of rhodamine-based fluorescent dyes,for example,its molar absorption coefficient is much larger than other fluorescent dyes,its wavelength is also longer,and the fluorescence quantum yield is also high,in addition to its special lactone ring structure,Will fluoresce according to the opening and closing,making it a wise choice for the synthesis of fluorescent molecular probes.In this experiment,based on its structure and past experience,three rhodamine-based fluorescent probes specific for copper ions were designed and synthesized.Their synthesis process is simple,does not require high environmental requirements,and pollution is relatively low.Many experimental results show that it’s excellent specificity and high sensitivity.It is a high-performance Cu²⁺fluorescent probe that can make a contribution in the field of water detection.In this paper,a fluorescent probe RhA was designed and successfully synthesized,which can be used in 2×10^-5mol/L HEPES-CH3CN（1:1,V/V,containing0.1mol/L Na NO₃,p H=7.4）test system solution.It recognizes Cu²⁺uniformly,and the color change and fluorescence change are obvious.Using the molar ratio method and the characteristics of longer color change time lag,and the color does not change significantly after adding EDTA,it is speculated that the reaction mechanism is a reactive fluorescent probe.The probe has obvious spectral changes for1×10^-6mol/LCu²⁺,it also has practical application significance for metal ion detection.RhB fluorescent probes are designed and synthesized,which can be specifically identified in the test system solution of 2×10^-5mol/L Cu²⁺,after adding an equivalent of Cu²⁺,the color of the test system solution changes significantly,and it is detected in real time by a fluorescence chromatograph,and there is also a significant spectral change.According to the molar ratio method and Gaussian calculation,and the change of fluorescence intensity before and after adding EDTA,it is speculated that the reaction mechanism is a complex fluorescent probe.For 1×10^-6mol/L Cu²⁺,there are still obvious spectral changes,and the detection speed is fast.Because the synthesis process of Rh B is simple,the environmental requirements are not high,and the pollution during the experiment is relatively small.Results show that it has excellent specificity and high sensitivity.It is a high-performance Cu²⁺fluorescent probe that can make a contribution in the field of water detection.In this paper,the RhC fluorescent probe is designed and effectively synthesized,which is specific in the test system of 2×10^-5mol/L Cu²⁺,the color of the test system solution changes significantly after adding Cu²⁺.Under the premise of the same amount of plasma addition,the color of Rh C changes the most.Adding a very small amount of copper ions can turn it into pink by naked eyes.According to the molar ratio method and with the addition of EDTA,the color gradually becomes lighter.It is speculated that the reaction mechanism is a complex fluorescent probe.When the test system contains 1×10^-6mol/L Cu²⁺,there are still obvious spectrum and color changes.It is a fluorescent probe that can realize immediate naked eye detection and has great application value.