Study On Ananlysis Methods For Heavy Metal Elements And Their Speciation In Environmental Samples

The high toxicity of heavy metal elements in environment,is difficult to control.Heavy metal elements have long incubation period,and are enriched along the food chain.They have been increasingly recognized and have been priority to remove pollutants.This dissertation is intend to develop new methods for trace or ultra-trace heavy metal elements in different types of environmental samples.Feed coal and its combustion solid by-products including bottom ash fly ash samples with different particle size from Luohe and Pingwei coal-fired power plants at Huainan,Anhui province,environmental water,Chinese traditional medicine,selenium-enriched rice,human albumin and human serum samples have been chosen as the research object.Combing some indirect methods,for example,ICP-AES,ICP-MS and HPLC-HG-AFS,with direct X-ray fine structure spectrum analysis method to establish some new analysis methods for the determination of trace or ultra-trace total heavy metal elements,available heavy metal edements and heavy metal elements speciation.The major research achievements are summarized as follows:(1)The high efficient extraction and analysis new method for available heavy metal elements in coal and its combusion by-products has been established.The new analysis method was developed for the inorganic arsenic speciation by high performance liquid chromatography coupled with hydride generation-atomic fluorescence spectrometry.The distribution regularities and migration patterns were found for available heavy metal elements in coal,fly ash,bottom ash and different particle size.(2)Several kinds of new analysis methods for trace or ultra-trace heavy metal elements(Pb,Cd and Al)in different types of environment samples have been developed by cloud point extraction coupled with graphite furnace atomic absorption spectrometry.The detection limits were 0.138 μg·L-11,0.007 μg·L-1 and 0.06 μg·L-1 the relative standard deviation(n=7)were 1.90%,2.08%and 3.60%,with enhancement factors of 18.3,17.7 and 34.8 with 10 mL sample solution for Pb,Cd and Al,respectively.(3)A cloud point extraction method for the preconcentration of ultra-trace bismuth in human serum prior to its determination by inductively coupled plasma optical emission spectrometry has been developed in this paper.An enrichment factor of 81 was obtained for the preconcentration of Bi using 25 mL solution.The limit of detection for Bi is 0.12 μg·L-1.The relative standard deviation is 2.30%.The values of recovery are changed from 92.3%to 94.7%.(4)Several kinds of new speciation analyis methods for trace or ultra-trace Cr(III)and organic selenium in environment samples have been developed by cloud point extraction coupled with furnace atomic absorption spectrometry.Under the optimal conditions,the detection limit are 0.02μg·L-1 and 0.08 μg·L-1,the relative standard deviation are 2.6%and 2.1%,recovery values are from 92.0%to 94.7%and from 90.3%to 106.0%,the enrichment factor are 83.5 and 82 for Cr(III)and organic selenium,respectively.(5)It is found that to control the process of sample pretreatment being freed from pollution,to choose sample pretreatment method,to test interference and to verify method accuracy,are key factors for establishing new analysis methods for trace heavy metal elements in different types of environmental samples.