The Study On The Interaction Of The Nucleic Acid With The Vitamin-metalion Complexes And The Analytical Application

Nucleic acids and protein are the material base of life, the research on which play an important role in the area of life sciences. Nucleic acid is an important bio-macromolecule and the carrier of genetic information. The quantitative analysis of nucleic acids is often involved in the analysis of biochemistry and other biological subjects. It is the common analytical item in the food examination and in the test of many biochemical medicines' separation and purification. The analysis results provide scientific basis for the disease diagnosis and the therapy.Probe technique is the important means for the research of nucleic acid's structure, function, qualitative and quantitative analyses. This thesis mainly studied the new nucleic acid probe and the intelligent analytical method of the vitamin. At the same time, this thesis discussed the interaction between the vitamin and nucleic acid ,and gave out the interaction mechanism between nucleic acids and vitamin-metal complexes.In the first section, we summarized the recent developments of the fluorescence and Resonance Light Scattering probes of nucleic acid and the analytical applications, and overviewed .the fluorescence probes of the vitamin medicine and the main means of the interaction between nucleic acid and the medicine.In the second section, we studied fluorescence enhancement of La³⁺-rutin -nucleic acid system, which was used for the determination of the nucleic acid. In Tris-HCl buffer, the fluorescence intensity of rutin-La³⁺ system can be greatly enhanced by nucleic acids and the enhanced intensity is in proportion to the concentration of nucleic acids in the range 8×10^-8-1×10^-5g/mL for fsDNA and 1×10^-7-9×10^-9g/mL for yRNA, their detection limits are 8×10^-8g/mL and 5.4×10^-8g/mL , respectively. The synthetic samples were satisfactorily determined. The interaction mechanism is also studied. It is considered that nucleic acid can bind with the complex of rutin-La³⁺ through electrostatic attraction and form a large rutin-La³⁺- nucleic acids complex. At the same time, nucleic acids provide an optimum hydrophobic environment for rutin-La³⁺ complex, resulting in the fluorescence enhancement of the latter. In addition, the hydrophobic environment of nucleic acids can also prevent the collision between complex and water molecules and decrease the energy loss of the rutin-La³⁺-nucleic acids system. Thus, the fluorescence quantum yield is improved and the fluorescence intensity of rutin-La³⁺ system is significantly enhanced.In the third section, we found that nucleic acid could enhance the scattering light intensity of Eu³⁺-vpp. Based on this, a new method for the determination of nucleic acid is proposed. In Tris-HCl buffer, the scattering intensity of vpp-Eu³⁺ system can be greatly enhanced by nucleic acids and the enhanced intensity is in proportion to the concentration of nucleic acids in the range 7×10^-8-1×10^-5g/mL for fsDNA,and its detection limit is 2×10^-8g/mL. The synthetic samples are satisfactorily determined. The interaction mechanism is also studied. It is considered that nucleic acid can bind with the complex of vpp-Eu³⁺ through electrostatic attraction and form a large vpp-Eu³⁺- nucleic acids complex.In the fourth section, it is indicated that the folic acid-Eu³⁺ system can emit the characteristic fluorescence of Eu³⁺. Based on this, a fluorimetric method for the determination of folic acid is proposed. The synthetic samples are satisfactorily determined. The test indicates that the folic acid can be oxidized by KMnO₄ and produce the purine of butterfly - 6- carboxyl acid ,which can bind with the Eu³⁺ and form a complex. It is considered that when the complex is excited, the purine of butterfly - 6- carboxyl acid absorbs the light energy and then transfers it to Eu³⁺ through intramolecular energy transfer. The experiments indicate that under the optimum conditions, the enhanced fluorescence intensity is in proportion to the concentration of folic acid in the range of 4×10^-8-4×10^-5g/mL,and its detection limit is 1.2×10^-8g/mL. The method has been used for the determination of folic acid in the actual samples.The chief characteristics of this thesis are as follows:1. It is indicated that nucleic acids can enhance the fluorescence in the rutin-La³⁺ system and apply it to the determination of nucleic acid in the synthetic sample. It is considered that nucleic acid can bind with the complex of rutin-La³⁺ through electrostatic attraction and form a large rutin-La³⁺- nucleic acids complex, and nucleic acids provides an optimum hydrophobic environment for rutin-La³⁺ complex, resulting in the fluorescence enhancement of the latter. In addition, the hydrophobic environment of nucleic acids can also prevent the collision between complex and water molecules. So the fluorescence intensity of rutin-La³⁺ system is significantly enhanced.2. Test indicated that nucleic acid can bind with vpp-Eu³⁺complex and form a large complex, resulting in the enhancement of scattering light of the system. Based on this, a new method of nucleic acid is proposed and is applied to the determination of nucleic acid in the synthetic sample. The methods are simple and stability.3. The investigation indicates that the oxidic product of folic acid can bind with Eu³⁺ and form a complex, which can emit the characteristic fluorescence of Eu³⁺ through the intramolecular energy transfer. Based on this, the new method of high sensitive determination of folic acid is established and is used for the determination of folic acid in the actual samples .The method is rapid and sensitive.