Determination Of Zinc In Non Fat Milk Powder And Copper In IMEP-6 By Isotope Dilution Mass Spectrometry

In this thesis, the certified method for the measuring total concentration of zinc in no fat milk powder component's analysis and the measuring total component concentration of copper in water component's analysis have been studied.Many investigations and studies about present situation of their analysis and measurement at home and abroad have been made. And the strong and weak points of those measuring methods have been evaluated in this thesis also. At the requirement of the high precise for the measurement of Referenced Standard Materials, certified methods for the total concentration's measurement of copper and zinc in reference standard materials of no fat milk power with Isotopic Dilution Mass Spectrometry (IDMS) has been established. The thesis reviews the produce, development, application, present situation and prospect of isotope dilution mass spectrometry (IDMS), especially the optimum isotope dilution proportion, the interference problem of the peak in isotope measurement and elimination method, and sample pretreatment methods are discussed in detail.The predominant advantages of IDMS are high sensitive, high precise, low interference and sample treatment need not to be quantitative .It has been called the best way for trace element analysis. In recent years, this method was used to certified reference standard materials.In this thesis, chemical pretreatment and separation of zinc in no fat milk power are discussed in detail. The process of the absorption of Zn on resin Dowex 1(8 was studied, and trace Zn can be quantitatively separated from 0.5M HCl. Zn is eluted with quartz sub boiling distillation water. The process of absorption of Cu on resin Dowex 1(8 was studied, and trace amount of Cu can be quantitatively separated from 6.0M HCl and eluted by quartz sub boiling distillation water. Isotope dilution mass spectrometry for measuring Cu in water was set up. These methods include chemical measurement. Relative Uncertainty of method is±2.14% for determination Cu, ±2.01% for determination Zn. The results of this study can meet the demand for certification of national grade reference standard materials.