The Development Of Novel Fluorescent Probes For HOCL,H₂S And Their Application In Environmental Analysis

At present,the hazards of ome pollutants in the environment such as hypochlorous acid(HOCl)and hydrogen sulfide(H2S)to environment and human were gradually recognized.HOCl is an extremely unstable weak acid that exists only in solution and is one of the important participants in the intracellular redox reaction.In human body,the high or low HOCl concentration affects human health.H2 S is a kind of physiological endogenous gas,but at the same time it has a strong toxicity,even if the environment concentration is very low also can cause human damage.The development of high performance HOCl and H2 S fluorescent probes is still a full of challenging and energetic field.In this paper,we synthesized and studied three fluorescent probes with coumarin as platform molecules and were used for the detection of HOCl and H2 S,respectively.In the second chapter,7-diethylamino-coumarin was used as the fluorescent group key to the strong quenching group 2,4-dinitrophenylhydrazine,obtain fluorescent probe Cou-HOCl-1,and then we used it for the detection of tap water and intracellular HOCl.The strong quenching fluorescence of dinitrophenylhydrazine and the rotation of N-N single bond in acetylhydrazide together leaded to a very weak fluorescence background.Upon treatment with 10 equivalent of hypochlorite,probe Cou-HOCl-1 achieved a dramatic fluorescence enhancement(fluorescence intensity enhanced up to 134-folds)and the sensitivity was significantly improved.The fluorescence intensity enhancement also showed a good linearity with HOCl concentration in the range of 0.1~40 ?M.The detection limit reached 0.052?M.At last,Cou-HOCl-1 successfully applied in detecting HOCl in tap water sample and living cells.In the third chapter,we synthesized the fluorescence quenching type hypochlorite colorimetric probe Cou-HOCl-2 with coumarin derivative and mercaptoethanol.Before and after adding HOCl,the UV absorption spectra of the probe showed a significant wavelength change,and the wavelength redshifted 44 nm.Simultaneously,the color of the solution changed from colorless to yellow.In thepresent of 100 ?M HOCl,the fluorescence intensity decreased by 20.27-folds.The ratio of UV absorbance at 442 nm and 398 nm showed a good linear relationship with the concentration of HOCl concentration in the range of 0.8~9 ?M,the detection limits was determined to be 0.667 ?M.Finally,the probe was used for the detection of HOCl in tap water and the results were satisfactory.In the forth chapter,We also developed a H2 S fluorescent probe Cou-H2 S with coumarin as a fluorescent group.In the presence of H2 S,the azide structure was destroyed and transformed into an amino structure,and the probe Cou-H2 S was excited to fluoresce.Cou-H2 S exhibits high sensitivity and selectivity to H2 S compared to other reaction sulfide species(RSS)probes.When 100 ?M H2 S was added in the test system,the fluorescence intensity of the probe was enhanced by28.72-folds.Fluorescence spectra shows,the probe has a good linear relationship with H2 S in the concentration range of 1 ?M ~ 10 ?M,the detection limit was determined to be 0.427 ?M,which was expected to be used for intracellular H2 S fluorescence imaging.