Studies On Resonance Scattering And Fluorescence Effects Of Nanoparticles Which Contain Sulfur, Selenium Or Iodine And Their Analytical Application

Partâ… Introduction Resonance scattering technology and the progress of its application in study nanoparticle systems and in analytical chemistry in resent years are introduced. The progress of preparation for Ag₂S and Se nanoparticles and the progress of ClO^-, ClO₂^-, ClO₂ and ClO₃-analysis are also introduced. Partâ…¡The Interface Fluorescence and Resonance Scattering Spectral Properties of Ag2S nanoparticles in Liquid Phase In the presence of sodium dodecyl sulphate (SDS), S^2- and Ag⁺ form Ag₂S nanoparticles. The resonance scattering and emission spectra of Ag₂S nanoparticles in liquid phase show that, Ag₂S anoparticles exhibit one strongest resonance scattering peak at 470 nm, and one strongest fluorescence peak at 470 nm when excited wavelength is at 200 nm. It is consistent that the effects on the concentration of TAA on the resonance scattering signals and fluorescence intensities and that of Ag⁺. There is the correlation between the fluorescence and resonance scattering. A new method for the determination of trace Ag⁺ with resonance scattering or fluorescence spectrum can be developed, owing to The Ag⁺ concentration is proportional to the intensity of resonance scattering or fluorescence at the range of 0-8.6 mg·L^-1. Part â…¢Resonance Scattering Spectral Properties of Se nanoparticles and Its Application to determination of vitamin C In the medium of hydrochloric acid, Vitamin C(VC) reacts with Se(â…¥) to form Se nanoparticles. The particles do not exhibit any absorption peaks in the zone of visible light, but exhibit four resonance scattering peaks and four fluorescence peaks at 340, 400, 470 and 520 nm. The effects of reagents concentration on the intensity of resonance scattering signals at 340 nm (ΔI340nm) are consistent with that on the fluorescence intensity at 470nm (ΔF470nm). There is the correlation between the interface fluorescence and resonance scattering. VC concentration is proportional to the ΔI340nm and ΔF470nm in the range of 0.05 to 4.0 mg·L-1 and 0.15 to 4.0 mg·L-1, respectively. Base on this fact, a new resonance scattering spectral (RSS) method has been proposed for the determination of VC. The detection limit is 0.01 mg·L-1. This method was used to determination of VC in pharmaceuticals and synthetic samples with satisfactory results. Part â…£A Fluorescence Quenching Method for the Determination of Trace ClO-with ClO--I--Rhodamine 6G system In the medium of hydrochloric acid, ClO-reacts with excessive I-forming I3-. It combine respectively Rhodamine 6G (RhG), Rhodamine S (RhS), Rhodamine B (RhB) and butyl-Rhodamine B (b-RhB) to form association particles, which result fluorescence quenching of the RhG, RhS, RhB and b-RhB systems at 550, 550, 580 and 580 nm, respectively. The fluorescence quenching is proportional to the concentration of ClO-at the range of 0.015-0.43, 0.020-0.35, 0.020-0.51 and 0.020-0.35 mg·L-1 and the detect limits for each system are 0.010, 0.016, 0.028 and 0.029 mg·L-1, respectively. Based on these facts, fluorescence quench methods for determination of trace ClO-have been proposed. Owing to the system of RhG having high sensitivity and good stability, it has been applied to the determination of ClO-in bleaching powder and liquid, with satisfactory results. Part â…¤A new Sensitive and selective Fluorescence Method for Determination of Chlorine Dioxide in Water Using Rhodamine S Based on the capacity of chlorine dioxide to decolorize Rhodamine dyes in the presence of ammonia/ammonium chloride buffer, a sensitive, highly selective method for the determination of trace chlorine dioxide has been developed. The fluorescence quenching is proportional to the concentration of ClO2 at the range of 0.0060-0.450, 0.0373-0.996, 0.0830-3.06 and 0.139-2.50 mg·L-1 and the detect limits for each system are 0.003, 0.027, 0.064 and 0.123 mg·L-1, respectively. With high sensitivity and good selectivity, the Rhodamine S has been applied to the determination of ClO2 in synthetic samples and samples, with satisfactory results.