Studies On The Application Of Laser Thermal Lens Spectrometry To Analysis Under Conditions Of Light Scattering Backgrounds

Laser Thermal Lens Spectrometry (LTLS) was developed as a high sensitive spectrometry based on the effect of photo-thermal. It has been widely applied to chemistry, physics, environmental and life science because of its extremely high sensitivity, low detect limit and the capability of measuring micro samples. Application of the LTLS to the determination of the light scattering samples and the investigation of the adsorption of silica has been studied in this thesis. The thesis is divided into six parts:I Review.A review of Laser Thermal Lens Spectrometry in terms of theory and applications to the analytical chemistry and the determination of samples under conditions of light scattering backgrounds is given.II Comparison of LTLS and Spectrophotometry for Absorption Measurements Under Conditions of Light Scattering BackgroundsLaser Thermal Lens Spectrometry has been theoretically and experimentally compare to the Spectrophotometry under conditions of light scattering backgrounds. Effects of scattering was studied in the different concentrations of Nile Blue solutions containing nanometer TiCh- And the determination of iron in human serum under the conditions of scattering caused by small protein particles remaining in the test solutionswas developed. It was shown that the Spectrophotometry based on the Lamber-Beer' Law has large determination errors in the light scattering solutions. However, LTLS was found to provide significant immunity from light scattering on the measurement process. There were good agreement between the theoretical predictions and the experimental results.HI Determination of Copper(II) in Chinese Herbal Medicine by Laser Thermal Lens Spectrometry under Conditions of Light Scattering BackgroundsDetermination of Copper( II) in scattering solutions by Laser Thermal LensSpectrometry was presented. The method was based on the complexation between Copper(II) iron and Zincon in a buffer solution (pHS.O). The effect of gelatin and different surfactants on the determination system was discussed. Gelatin can improve the selectivity of the method. Calibration curve was found to be linear over the range of 0 to l.Oug.mL"1 of Cu2+ at 600nm. Coefficient of correlation was 0.9984 and the limit of detection was 2ng.mL"1. The method has been applied to determination Copper in Chinese herbal medicine successfully.IV Determination of Zinc( II) in Human Serum by Laser Thermal Lens Spectro-metry Under Conditions of Light Scattering BackgroundsA simple and effective method for the determination of zinc( II) in human serum by Laser Thermal Lens Spectrometry was developed. The method was based on dissociation of Zn + from protein in diluted chlorhydric acid and formation of the blue complex with Zincon in a weak basic medium. The effect of scattering caused by the presence of small protein particles remaining in the solution after the deproteinization step was investigated by making a comparison between the LTLS and spectrophotometry. The LTLS has been applied to the analysis of Zinc( II) in human serum. The linear range was 0 to 1.6 ug.mL"1 for Zn2+ at 620nm, the limit of detection was Ing.mL"1 and the relative standard derivation is 1.8%.V Investigation of the Adsorption of Silica by Laser Thermal Lens SpectrometryLaser thermal lens Spectrometry was applied to investigation of the characteristics of silica's adsorbability. The adsorptive dynamics were investigation and the adsorption isotherms were made at 20 癈. The adsorptive rate, the equilibration constants and the maximum adsorptive capacity of silica gel. were measured. The effect of temperature on adsorption was discussed. It was found that the LTLS could applied to the investigation of the adsorption in solutions successfully. The Langmuir equation could be adaptable to silica sorbents, The maximum adsorptive capacity of Kiese gel60HF254 was 3.10xlO~6mol.g-l and the adsorbability of silica G was comparatively weak.VI Investigation of Solid Chelation and the Adsorption of Chelat by Laser Thermal Lens Spectr...