| Nucleic acid is one of the fundamental materials of life. It plays an important role in life activities. The store of information of heredity and synthesis of proteins is its most important function. During the past century, people have made much breakthrough in the studies on nucleic acid with great efforts and extended the study field of nucleic acid. The study of nucleic acid is more and more becoming an active field in life science. The quantitative determination of nucleic acid is of great importance in fundamental research and in clinical diagnosis.Currently, there are three main ways to analyze nucleic acid quantitatively: 1. Photometric analysis. It includes the photometric analysis based on the quantity of phosphorus, or on the quantity of sugar and on the absorption of the base pairs. 2. Fluorescence analysis. It is based on the enhancement of the fluorescence of various intercalating dyes. 3. Resonance light scattering (RLS) technique. It is proved that enhanced RLS signals are available in the long assembly of agents on the biological template. With these enhanced RLS signals, sensitive methods of nucleic acid determination have been proposed. Three kinds of agents are employed in resonance light scattering technique: porphyrin combinations, metal complexes and organic small molecular dyes.Among the methods mentioned above, spectrophotometry is complicated and time consuming and not yet sensitive enough. Although fluorescence spectrophotometry has excellent selectivity and sensitivity, it suffers from the high expenditure and toxicity of the fluorescence reagents. As a novel technique, RLS method is simple, rapid and has satisfactory selectivity and sensitivity, but is not so perfect too, especially in its theory and the cause of RLS. There is a long way to go before it can be applied in analytical chemistry perfectly.The interaction forms between nucleic acids and small molecular are mainly two kinds, covalence interaction (irreversible interaction) and non- covalence interaction (reversible interaction). Non-covalence interaction includes three binding modes concerning the interactions of dyes with nucleic acids: one is the so-called inercalative binding in which the dyes intercalate into the base pairs of nucleic acids. Another is groove binding in which the dyes bound on nucleic acids are located in the major or minor groove. The final one islong-range assembly on the molecular surface of nucleic acids because of electrostatic force and hydrophobic force. The last is the primary reaction mechanism of RLS probes and nucleic acids in the nucleic acids RLS determinations.Based on a lot of documents and conditions of our laboratory, this thesis establishes several new determination methods of nucleic acids by means of resonance light scattering technique. These methods are simple and rapid with excellent reappearance, selectivity, sensitivity and wide linear coverage.This thesis is composed of five chapters:Methyl violet 6B (MV6B) is a triphenymethane dye, and it was firstly used to determine nucleic acids by resonance light scattering technique. At pH 10.80, the interactions of MV6B with nucleic acids give strong RLS signal at 386.0 nm. A new method of quantitative determination for nucleic acids in aqueous solutions has been developed. The linear range for fsDNA and yRNA is 0.083-1.0 g/mL and 0.075-0.8 g /mL. The limits of detection were 82.6 and 74.3 ng/mL for fsDNA and yRNA, respectively.Victoria blue B (VBB) is a dipheny naphthylmethane dye. In the buffer solution (pH 6.7-6.9), the RLS of VBB is enhanced a little by nucleic acids. In the system of cationic dye-nucleic acid-CTMAB, nucleic acid acts as the template to promote the assembly of cationic dye and surfactant to form cationic dye-nucleic acid-CTMAB assembled associate. During the formation of associate, nucleic acid draws close the distance between cationic dye and surfactant to form large associate. Therefore the RLS intensity of cationic dye is greatly enhanced. The enhanced RLS intensity at 390.0 nm was proportional to t...
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