Applications Of Resonance Light Scattering Technique In Pharmaceutical And Nucleic Acid Analysis

Since its foundation, the light scattering technique has been extensively applied to studies of macromolecule polymer sciences, colloid sciences and life sciences by continually perfecting and developing. In 1993, Pasternack et al. used a common fluorescence spectrophotometer and constructed a resonance light scattering (RLS) technique. The technique attracted attention due to its simple manipulation, high sensitivity and convenient operation. Since then, RLS technique has been extensively and successfully utilized in various fields of analytical studies. However, the RLS has easily got external disturbance by adopting the intensities at single wavelength as the token means, resulting in instable signals. In such case, it is necessary that we can make further studies, and overcome the drawbacks of RLS technique. Based on the studies of common light scattering, we established a new dual wavelength light scattering and fluorescence emission ratiometry, and applied for biomedical and pharmaceutical analysis. The thesis consists of three sections as follow:(1) In the medium of HAc-NaAc buffer solution ( pH 4.6 ), a light scattering analytical method for the determination of ciprofloxacin was established based on the interaction of ciprofloxacin with sodium tetraphenylboron, which could result in light scattering (LS) signals characterized at 385.0 nm. It was found that the enhanced LS intensities (ΔI_LS) were in proportion to the concentrations of ciprofloxacin in two ranges. The linear ranges of ciprofloxacin are 0.03～0.2μg/mL and 0.2～2.5μg/mL. The detection limits for ciprofloxacin are 7.4 ng/mL and 2.7 ng/mL, respectively. The effects of the pH, the concentration of polyethyleneglycol 600 solution, the concentration of sodium tetraphenylboron solution and foreign substances on the determination of ciprofloxacin were investigated. Compared with the high performance liquid chromatography method, the present light scattering method can be applied to the determination of ciprofloxacin in ciprofloxacin hydrochloride tablets.(2) In the sodium dodecyl benzene sulfonate (SDBS) micellar system, a sensitive method for the determination of I^- was established based on the interaction of AgNO₃ with I^-, which can produce steady AgI colloid and result in strong enhanced resonance light scattering (RLS) signals characterized at 437.0 nm. It was found that the enhanced RLS intensities (ΔI_RLS) were in proportion to the concentrations of I" in the linear range of 0.03～4.4μg/mL, and the limit of determination for I^- is 2.6 ng/mL. The present method has been used for the determination of micro amounts of iodine in synthetic samples with the recovery of 99.3-106.7% and RSD less than 2.8%.(3) In the medium of Britton-Robinson (BR) buffer solution ( pH 9.62 ), a binary complex formed between acridine orange (AO) and fish sperm DNA (fsDNA) via electrostatic interaction, resulting in strong enhanced light scattering (LS) signals withλ_ex 272.0 nm and fluorescence quenching withλ_em 534.0 nm. Thus, a light scattering and fluorescence emission (LS/FL) ratiometry method using the coexistent light scattering and fluorescent emission signals has been proposed. It was found that the light scattering and fluorescence emission ratio values (I/F) were in proportion to the concentrations of fsNDA in the linear range of 0.02～1.4μg/mL, and the limit of determination for fsDNA is 5.7 ng/mL. The method has been used for the determination of nucleic acid in synthetic samples with the RSD of 1.3 - 2.0 %. The experimental results indicated that the LS/FL ratiometry method we put forward in this thesis has higher sensitivity and wider linear range than literature reported light scattering method or fluorescent emission method of general single wavelength measures.