Design And Synthesis Of Fluorescence Probe Based On Isophorone And Its Performance For Mercury Ions Recognition

Mercury is one of the most toxic heavy metals widely found in water and soil.It harms the natural environment and human health.It is mainly absorbed by plants and transmitted to humans through the food chain,thus posing a great threat to human health.When people are exposed to mercury vapor or abnormal levels of mercury ions for long periods of time,they can cause damage to the kidneys,brain and central nervous system.Therefore,the detection method of mercury ion has become the focus of environmental science.Fluorescence detection method has attracted much attention because of its advantages such as high sensitivity,high selectivity and simple operation.However,most fluorescent probes used for mercury ion detection have problems such as slow reaction speed and poor water solubility.Based on these,we designed and synthesized three small molecule fluorescent probes for the detection of mercury ions.The specific work is as follows:(1)Probe XN-1 uses isophorone as fluorophore and vinyl ether as recognition group.The probe recognizes mercury ions through hydroxylmercuric reaction,and the fluorescence is turned on.With the addition of mercury ions,the probe has a strong emission peak at 675 nm,with a maximum enhancement of 55 times.(2)Due to the interference of fluorescent background of probe XN-1 and the error caused by probe load,retention and equipment factors,we designed and synthesized probe XN-2.Choosing dithiolane as the recognition group of XN-2,it was induced by mercury ion to undergo deprotection reaction from thioacetal to aldehyde group,which changed the ability of functional group to push and pull electrons,resulting in ICT effect,resulting in fluorescence emission redshift.The optimal reaction system of the probe was explored,and the optimal reaction condition was determined to be Et OH-PBS(v/v = 3/7,p H = 7.4).After the addition of mercury ions,the fluorescence spectrum redshifted from 574 nm to650 nm,the solution changed from yellow to red,and the reaction was stable in 30 min,with a calculated detection limit of 0.1 μM.(3)In order to further improve the water solubility of the probe and speed up the reaction,we designed a ratiometric fluorescent probe XN-3 containing hydrophilic carboxyl group.The ultraviolet absorption spectrum and fluorescence spectrum of the probe were analyzed and tested.It was found that XN-3 has the advantages of good water solubility,fast reaction speed to mercury ion and high selectivity.In practical application,the probe was made into portable test strips and used for the analysis and detection of mercury ion in Chinese medicinal materials.