A New Method For The Fluorescent Analysis Of Thiol Compounds

Fluorescence analysis has been widely used to detect the thiols because of its high sensitivity, fast response and low cost. It is very important to develop the fluorescence probe with high sensitivity and high selectivity for identification and quantitative detection of thiols since the majority of thiols compounds possess no fluorescence. The content of this thesis is listed as follows:Firstly, the research progress of thiols fluorescent probes was reviewed in detail according to reaction mechanism herein.Secondly, a fluorescent probe 5-maleimide-8-hydroxyquinoline(Compound I) was synthesized using 5-amino-8-hydroxyquinoline as a raw material and further characterized by FT-IR and 1H NMR. The fluorescence properties were also measured before and after reaction of Compound I with Cysteine(Cys). The reaction conditions and the effect on the fluorescence of some concomitants were studied. It demonstrated that Compound I possessed high selectivity to detect Cys quantitatively. The linear equation was y=152.84x+11.39 and the correlation coefficient was 0.9992. Range of linearity for the concentration of thiols was 0.1-6.0μmol/L. The limit of detection(LOD) was 5.29×10-9mol/L.Thirdly, the fluorescence properties were also measured before and after reaction of N-butyl-4-nitro-1,8-naphthalimide(Compound II) with GSH. The reaction conditions and the effect on the fluorescence of some concomitants were studied. A new method of spectrofluorimetric analysis of thiols was also proposed. Experimental results showed that the optimal p H value of reaction changed from 11.0 to 8.0-10.0, the emission spectra of products shifted from 500 nm to 470 nm and the reaction time was shortened from 120 min to 30 min under the temperature of 50 oC at the presence of CTAB. The fluorescence intensity of products was improved greatly and Compound II possessed high selectivity to detect GSH quantitatively. The linear equation was y=266.47x-9.39 with the correlation coefficient of 0.998. Range of linearity for the concentration of thiols was 0.05-10.0μmol/L. The limit of detection(LOD) was 7.88×10-10mol/L.Finally, the copper complexes of PAA nanometer fluorescent microsphere containing acridine(PAY) were prepared and its fluorescence property was also evaluated. The optimal detection conditions of GSH were studied. Among the tested amino acid, only GSH could improve fluorescence intensity of the copper complexes of PAA nanometer fluorescent microsphere. The good linear relationship was found to fluorescence intensity versus the concentration of thiols. The linear equation was y=26.058x+0.5546 with the correlation coefficient of 0.9996. Range of linearity for the concentration of thiols was 1.0-20.0μmol/L. The limit of detection(LOD) was 2.38×10-7mol/L.