Determination Of Mercury, Silver, Rare Earth Elements And Uranium By Atomic Fluorescence Spectrometry

It will harm human body exposed to mercury or silver for long time. The result of studying the toxicity of mercury shows that even trace amounts of mercury can deteriorate the human health. WHO suggests the content of silver in drinking water should not exceed0.1mg· L-1, meanwhile, USA Environmental Protection Agency recommends its maximum value be0.05mg·L-1. The content of rare earth elements has an important influence on the properties of alloy and the growth of crops. Uranium has a great influence on the biological health. Uranium and its decayed products are radioactive, once their entering food chain will pollute foods, and posing a great threat to human and animals. It is very essential to establish a quick and easy determination method to determine these elements.In this study, organic reagent extraction was used to separate mercury from its matrix. Then, the content of mercury was directly determined by atomic fluorescence spectrometry. As silver, rare earth elements and uranium can not be directly determined by atomic fluorescence spectrometry, the content of these elements was indirectly determined by measuring the content of mercury or arsenic which formed complexes with the target elements. A new method for determination of these elements by online extraction-atomic fluorescence spectrometry was established.In the medium of0.5mol·L-1hydrochloric acid, mercury in the sample was extracted by butanol to separate from its interference matrix and achieve enrichment. Experimental conditions were optimized. The contents of mercury in arsenic, tin and tin ingot were determined. The method detection limit was0.20μg·L-1, the relative standard deviation was2.3%, and the recoveries were from94.5%～99.2%.In acidic condition, silver ions could form stable compound Ag2HgI4with mercuric iodide. Ethyl acetate was chosen to extract Ag2HgI4into the organic phase. Then the content of mercury was determined by Hydride Generation-Atomic Fluorescence Spectrometry in terms of silver content. Experimental conditions were optimized. The silver ion contents in seawater samples were determined. The method detection limit was8.8ng·mL-1, the relative standard deviation was3.5%, and the recoveries were from99.6%～104.4%.Rare earth elements could generate stable complex with Arsenazo Ⅲ. In the presence of two benzene guanidine, the complex could be extracted into the organic phase by butanol. The potassium permanganate was used to destruct the stable complex. Then the arsenic content was determined by atomic fluorescence spectrometry in terms of the rare earth elements content. Experimental conditions were optimized. The contents of rare earth elements in steel samples were determined. The method detection limit was0.16μg·mL-1, the relative standard deviation was2.1%, and the recoveries were from94.8%～98.5%Uranium could generate stable complex with Arsenazo III. Three butyl phosphate was chosen to extract the complex into organic phase in order to enrich the target element and separate from the matrix. Then, the arsenic content was determined by atomic fluorescence spectrometry in terms of the uranium content. The experimental conditions were optimized and the contents of uranium in coal were determined. The method detection limit was0.09μg·L-1, the relative standard deviation was2.3%, and the recoveries were from94%～109%...