Studies On The Separation And Preconcentration Behavior Of Scatter Elements And The Detemination Of Atomic Absorption Spectroscopy

On the foundation of numerous references, the behavior and mechanism about separation and preconcentration of the rare disperse metals, such as gallium and germanium, have been checked respectively; in addition, the method has been applied to determine the metals by atomic absorption spectrosocopy(AAS). Furthermore, the effects and the mechanism of different matrix acting on gallium in the graphite furnace of AAS, with the behavior on gallium atomization, have been discussed in detail.This paper consists of three chapters.In chapter 1. The effects on gallium atomization in the pyrogenated graphite tube imposed by different martix modifier and different coating was detailedly discussed in this paper. On this basis, the mechanism of gallium atomization in the moiybdenum-coated pyrogenated graphite tube using Ni(NO3)2 as martix modifier was studied furthermore; in addition, the parameters of the operation were optimized ; and as a result, a new method improved in many aspects was developed to detect trace gallium in complicated sampler. The outcomes of practical applications indicated that the method can satisfy the requests of analysis and that the manipulations were simple to achieve. The characteristic content, the detection limit, the adding recoveries were 2.12× 10-11 g , 1.4× 10-10g , 97.4-102.7% respectively and the relative standard deviation was less than or equal to 3.6%(n=11).In chapter 2. A novel new method was described for the indirect determination of trace germanium in fly ash based on the extraction using TBP by FAAS. The steady heteropolymobdate of germanium was formed in 0.3mol/L nitrate and was extracted into TBP phase; afterwards, indirect determined germanium was achieved with determination of molybdenum in TBP phase by FAAS. The RSD(n=ll), the adding recoveries, the characteristic content , and the linear range of the method were 4.6%, 97.6%-101.2%, 21.86 ng mL-1/0.0044A, 200ng.mL-1- 2000 ng.mL-1 respectively. The equation of linear regression was A=0.2668C-0.0243 with the r=0.9986.In chapter 3. By means of ion exchange chromatography, the micro amount of gallium was separated from common metal elements successfully, using strong base type anionic resin as stationary phase. Gallium preconcentrated in chromatographic column was eluted with distilled water, and then separation and determination by AAS were carried out. The recoveries of gallium was 95.2% ~99.9%. Simultaneously, the optimized conditions of separation and preconcentration, including the specific properties of packed column the form of gallium packed in exchanger the verity of eluent and the factors of eluate have been discussed respectively. The whole method has been applied to analysis the practice sample with satisfactory result.In a word, by numerous systematic and scrupulous experimental research, the method about selectivity separation andpreconcentration of scatter elements had been found. After that, the method was contacted with AAS. Thus, a simple and practice method to detect the metals by AAS and GFAAS have been established successfully with high sensitivity. All these work make the methods full of practical and theoretical value.