Study On The Resonance Light Scattering Of Cyanine Dyes And Their Analytical Applications

Cyanine dyes bear the merits of large molar absorbability and high quantum efficiencies. The spectra of cyanine can be extended from visible region to near infrared (near-IR) by tuning the length of the conjugate chain, and a better sensitivity and selectivity would be obtained if the measurement performed in near-IR region, a region of little interference from background. Furthermore, due to a strong ability of aggregates, cyanine is sensitive to environment and its spectra may be varied with the change of microenvironment, which would result in a dramatically change of RLS signals. The RLS measurement in near-IR region would combine the advantages of high sensitivity of RLS and the low background interference, very suitable for environmental and biological assays. Based on a lot of documents and conditions of our laboratory, this thesis developed several new methods for the determination of surfactant and nucleic acids employing two kinds of synthesized cyanine compounds as probes, by means of resonance light-scattering technique, and the interaction mechanisms were investigated by various spectra. The thesis was consisted of six chapters.In chapter 1, classifications, various qualities and application of cyanine were firstly summarized. Emphasis was focused on aggregation qualities of cyanine and their recent research progress in the fields of biological system. Then, basic theory and application of resonance light scattering (RLS) were summarized. Finally, the research proposal for this dissertation was presented.In chapter 2, the apparatus, reagents and synthesis of two kinds of probes used by this work were described.In chapter 3, the resonance light scattering (RLS) spectra of near infrared cationic cyanine I dye and anionic surfactants sodium dodecyl benzenesulphonate (SDBS) in pH 6.30 phosphate buffer medium were studied, and the mechanisms were also discussed. It is shown that strong interaction of cyanine I and anionic surfactant have been occurred. Due to formation of ion association complexes, the aggregations of cyanine have been changed, which resulted in an increase of RLS and the maximum RLS peak was at 823nm. The enhanced intensity of RLS was proportional to the concentration of SDBS. The sensitive method for determination of anionic...