Detection Of Trace Elements In Aquatic

The studies in the thesis are summarized as follows:(1)A new method for the absorptiophotometric determination of zinc with the color reagent 2-(5-bromo-2-pyridylazo)-5-dimethylamino -phenol is reported in this paper.It is found that the zinc(Ⅱ)ions can react with 5-Br-DMPAP and OP at pH9.0,to form a violet red complex. The absorption maxima of the complex lies at 556nm.Beer's law is obeyed over the range of 0～25μg/25mL for zinc(Ⅱ).The apparent molar absorptivity isε=7.74×10⁴L/mol·cm.The detection limit is found to be 0.2μg/25mL.The method has been used for the determination of zinc in freshwater products with satisfatory results.(2)Trace beryllium in fish was determined by the microwave digestion technique and graphite fuenace atomic absorption spectrometry. The linear range is 0～10μg/L,the detection limit is 0.076ng/g,he recovery was 98.7%and the RSD was 2.64%.The method was accurate,rapid and simple,the results of determination by this mathod were compared with acid digestion at atmo-sphere were same.It is used in the routine analysis of fish.(3)It is reported in this paper that the microwave digestion techniaue is used in the ion-exchange-separation hydride generation atomic fluorescence spectrometry determination of trace selenium in foods.The various factors affecting fluorescence intensity of selenium were examined in details.The optimum conditions for the determination is tested and discussed.The detection limit is 0.15ng/mL.The recoveries of the method are 93.7%-100.9%,RSD＜2.8%.This method is accurate, quick-acquired and convenient.It is used in the determination of trace selenium in foods with the result is satisfactory.(4)The essay develops a new method of preconcentration seperation technique with P₅₀₇extraction chromatograph resin with a sample of ICP-AES simultanuously determining La,Sm,Y and Nd. Under the optinum condition,the detection limits of La,Sm,Y and Nd are 0.0052,0.0070,0.0093,0.0161μg/mL respectively.The recoveries of the method are 93.4%～102.5%,RSD1.3%～3.6%.This method is accurate,quick-acquired and convenient.It is used in the determination of freshwater products with the result is satisfactory.