| Transition metal ions have played a crucial role in the field of environment and biology,and design and synthesis of receptor molecules with selective recognition have attracted much attention in recent years.Fluorescent probe have used on the biological and environmental analysis owning to extremely broad response range,high selectivity,real time monitoring capability,anti-interference and low detection limit and so on.However,most fluorescent probes can mainly in organic solvent,and it is difficult to solve in the water,which has limited its practical application in environment and biological areas.In order to solve the above problem,in this dissertation,we designed and prepared two novel fluorescein-based fluorescent probes:water-soluble small molecule probes(ACFH)and polymer probe(PAFM),investigated the probe mechanism and their application in environment and biology.The main research contents of this dissertation are as follows:1.The The development of fluorescent probe mmaterials was reviewed.and influencve of molecular structure of samll molecules and polymers on their properties was discussed.2.Fluorescein-based small molecule probes(ACFH)was designed and prepared,and its structure and properties of probes molecule were characterized by UV-vis,FTIR,1H NMR,FL,elemental analysis,and so on.Additionally,the optical properties of the probe was investigated in detail,hinting the probes(ACFH)was able to selectively recognize Hg2+ in pure water,and detection of Hg2+ is not interfered with the addition of other ions and showed very high sensitivity toward Hg2+.Meanwhile,the linear range of the probe in the optimal detection conditions(pH=7)is 1-100 nM,and the detection limit of ACFH was 0.86 nM.The mechanism of the detection of Hg2+ was studied via Job-Plot curves and a comparison of NMR spectra before and after Hg2+ were added into the probe,suggesting the complex ratio of probe to Hg2+ was 1:1.The mechanism of the detection of Hg2+ was mainly based on complexation-ring opening process or complexation induced ring opening mechanism of fluorescein lactam,namely,first forming the complexation of probe with Hg2+,following hydrolyzation ring opening reaction.3.Base on the small molecule probe,the polymer probe(PAFM)with well water solubility was synthetized by the copolymerization of the ACFH probe and acrylamide.The structure of polymer was measured by UV-vis,FTIR,1H NMR,FL,Elemental analysis,and so on.The optical properties of the probe were explored in detail.It was found that the probes(PAFM)was also able to selectively recognize Hg2+in pure water,and detection of Hg2+does not disturbed by the addition of other ions and show high seletivity.The polymer probe possesses identification stability of Hg2+about 3 min and displays very fast real-time detection performance.Under optimum pH conditions(pH=7)the linear range of the probe is 1-10 nM,and the detection limit of PAFH was 0.4 nM.The mechanism of probe for detection of Hg2+ was investigated by Job-Plot curves and a comparison of NMR spectra before and after Hg2+ were added into the probe,suggesting the complex ratio of probe to Hg2+ was 1:1.The mechanism of probe for detection of Hg2+ is similar with that of above small molecular probe based on complexation-ring opening process.4.Both the small molecule probe and polymer probe have well water solubility,and thus it was applied for detecting Hg2+ in lake water and tap water in complex environment,in addition,both types of probes allow the quantitative analysis of Hg2+ in lake water and drinking water.Their detection recoveries of ACFH and PAFM were over 92%.Simltaneously,probes were also applied to biological cell experiments for detection of imaging of Hg2+.Compared with the small molecule polymer probe shows well solubility in water,lower detection limit and well cell permeability.The cytotoxicity of the probe was measured,found that the probes have less cytotoxic in the concentration of probe was less than 100 μM.Therfore,the probes were able to trace intracellular Hg2+ by fluorescence imaging.. |
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