Analysis Of DNA By The Fluorescence Probe Of RE Complex And Its Application In The Study Of The Interaction Between Heavy Metal And DNA

In recent years, ions as luminescence probes and its application have attracted more and more attention, and will become a normal analytical method, which is widely used in the biology, medicine, chemistry and so on, especially in the study of the structure and function of the biological macromolecules. At present, many of these fluorescent DNA probes are highly toxic and can be mutagenic, especially if the union to DNA is irreversible. Therefore, the search for low toxic, selective and sensitive DNA probes is an active field of research. The dissertation consists of the following four parts.In the first part, the rare-earth luminescence probes and its application in the study of the pharmaceutical analysis, biological substances analysis and the structure and function of the biological macromolecules were systemically reviewed, which includes my research works in the above fields. The following study on the rare-earth luminescence probes and its application was developed. (1) The artificial synthetic derivative of diacylated pyrazolone, 1,6-bi(1'-phenyl-3'-methyl-5'-pyrazolone-4'-) hexanedione(BPMPHD) is a new fluorescent chelating agent for RE ions, which can form a large ion association with Dy³+ and the cation surfactant cetyltrimethylammonium bromide(CTMAB), and can emit the intrinsic fluorescence of Dy3+. In this system, some rare earth ions such as Gd3+, Y3+, La3+ can exert an evident fluorescence enhancement effect, this is a newly found co-luminescence system. From this, a rapid, simple and sensitive method was developed for the determination of trace amounts of Dy3+ . The results indicated that the fluorescence intensity of the system was a linear relationship with the concentration of Dy3+ in the range of 1.0× 10^-7- 1.2×10^-5 mol/L, the detection limit(S/N=3) was 3.0×10^-8mol/L. (2) Experiments indicated that terbium( III) ion could form complex with norepinephrine, then emitted its characteristic fluorescence. In this paper, the fluorescence reaction between terbium(III) ion and norepinephrine was studied in detail. Thus a new method for the determination of norepinephrine was put forward.The fluorescence intensity was measured in a 1 cm quartz cell with excitation and emission wavelengths of 300, 545nm, respectively. The result showed that the fluorescence intensity of the system presented a linear relationship with the concentration of norepinephrine in the range of 0.01-50 u g /mL, the detection limit(S/N=3) was 1.0 ng/mL. (3) Experiments indicated that cerium(IV) ion which could not emit fluorescence was deoxidized to cerium(III) ion which could emit characteristic fluorescence by ascorbic acid in water solution, while sodium triphosphate added could greatly enhance the fluorescence intensity of the system. From this, a indirect sensitive method for determining ascorbic acid was developed. The fluorescence intensity of the system was measured in a 1 cm quartz cell with excitation and emission wavelengths of 303 nm and 353 run, respectively. The results showed that the fluorescence intensity of the system presented a linear relationship with the concentration of ascorbic acid in the range of l.OxlO"7 -6.0x10"6 mol/L, the correlation coefficient r was 0.9989, the detection limit(S/N=3) was l.OxlO"8 mol/L. (4) The experiments indicated that terbium(III) ion could complex with the fluoroquinolone, then emitted the characteristic fluorescence of terbium(III) ion. While added the surfactant of SDBS, the fluorescence intensity of the system was greatly increased. From this, a sensitive method of determining the fluoroquinolone was set up. The fluorescence intensity was determined by a 1-cm quartz cell with the excitation wavelengths of 300nm and the emission wavelengths of 545nm. the detection limit could obtain 10"9 mol/L.In the second part, the fluorescence enhancement of the fluoroquinolone -Tb3+ complex by DNA was studied. A sensitive fluorescence method for the determination of DNA was developed. It was found that the fluorescence probe of the fluoroquinolone-Tb3+ complex not only had higher sensitivity for determining the single-stranded content of DNA at nanogram levels than most of the reported probes, but also could directly determine double-stranded content of nature calf thymus DNA (except NFLX-Tb3+).The fluorescence probe of the fluoroquinolone-Tb3+complex can also be used to study the interaction between the contaminants and DNA. In addition, these DNA probes are environment friendly.