| Thallium has been identified to be an environmentally significant element because of its toxic effects.But as the concentration of Thallium in the nature is belowμg·g-1 level,the development of new methods for selective separation, preconcentration,purification and determination of this metal continues to be a challenging problem.The need for highly sensitive and reliable method for the determination of ultratrace level Thallium has been recognized in analytical and environmental chemistry.The kinetic analytical methods are made using the relations among chemical reaction rates,reactant concentrations and catalysts.The catalytic kinetics has high sensitivity,excellent selectivity,inexpensiye instruments and simple operation.It is one of the effective methods for detecting trace metals.In this thesis, the measurements of trace Thallium(â… ) were established based on its catalytic effect on the chemiluminescence reaction and their reaction mechanisms were also discussed.The main contents of the present work are as follows:(1) A new catalytic kinetic spectrophotometric method was developed for the determination of Thallium(â… ) based on its catalytic effect on the system of Luminol and hydrogen peroxide.The temperature and reaction time of the system and its effect of coexisting ions were also investigated in detailed.The linear range of the method was 0.05～0.2μg·mL-1 for Thallium(â… ).The linear equation wasΔA=0.365+0.088C(μg·mL-1)(r=0.9989) and the detection limit was 0.0078μg·mL-1.It has been applide to the determination of trace Thallium(â… ) in mineral sample with RSD of 1.34%and recovery of 98%～102%.(2) At the first part of the foundation up,using a high-performance liquid chromatography equipped with the UV detector to the determination of trace thallium, set up a new determination of trace thallium Ways.This new method not only combines high-performance liquid chromatography separation performance and the chemiluminescence reaction of high sensitivity,and easy conditions.Three different kinds of surfactants,cetrimonium bromide(CTMAB),sodium dodecyl sulphate (SDS),and Tween-80,are also investigated to improve the detection sensitivity.In optimum conditions,a highly selective and sensitive method for detecting trace Thallium(â… ) has been established.The detection limit is 0.0073μg·mL-1,the relative standard deviation for six determinations of 0.04μg·mL-1 Thallium(â… ) is less than 4.0%, and the linear range of determination is 0.02～0.1μg·mL-1.(3) A new method for the determination of trace element thallium was proposed based on the catalysis of Thallium(â… ) on the photochemical reaction of lucigenin and hydrogen peroxide whit UV radiation.The light sources,radiation time of the system, a possible mechanism and its effect of coexisting ions were also investigated in detailed.The linear range of the method was 0.05～0.3μg·mL-1 for Thallium(â… ).The linear equation wasΔA=0.0854+0.0892C(μg·mL-1)(r=0.996) and the detection limit was 0.0081μg·mL-1.By using the method in the determination of trace Tl(â… ) in mineral sample,the RSD and recovery were 3.27%and 97%～103%,respectively, the results had shown that the method was satisfactory.
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