| As the rapid development of modern industry,the content of metal elements in the environment was rapidly increasing that posing a serious threat to people's health.Therefore,development of the rapid and accurate methods to detect the trace metal elements in the environment is necessary.It is very difficult to directly detect the content of metal elements in environmental samples due to the lower content of analyte in the environment.Based on this reason,we often need to take the separation and preconcentration procedures for trace elements.As a new sample pretreatment technology,the liquid-liquid microextraction?DLLME?technique has the advantages of simple operation,small sample amount,low cost and high enrichment factor.Therefore,in this paper,DLLME technology was combined with energy dispersive X-ray fluorescence spectrometer?ED-XRF?and inductively coupled plasma mass spectrometry?ICP-MS?to established the relevant detection methods.The main research work are described as follows:1.The application and progress of DLLME in separation and enrichment in recent years were summarized.The influencing factors of DLLME technology were discussed and the study background,the sketch of experiment scheme were also introduced.2.A novel method based on DLLME and ED-XRF with thin sample technology for the preconcentration and determination of Cu?II?in environmental water samples was developed.In the present study,sodium diethyldithiocarbamate?DDTC?was used as the chelating agent.The best conditions were obtained as follows:50?L carbon tetrachloride,0.4 mL methanol,pH=8,DDTC concentration was 0.03 mg·m L-1and extraction time of 3min.The quantitative analysis was evaluated by the internal standard method under the optimal conditions,the recoveries were in the range of 97%105%along with the detection limit of 0.08?g·L-11 and the enrichment factor was 114.The repeatability of the developed method was also evaluated by six parallel tests for two actual samples with the relative standard deviation?RSD?were 3.1%and 3.3%,respectively.The results were satisfactory.3.Samples were treated by microwave digestion,a novel method based on DLLME and ED-XRF was established to detect of trace gold in environmental soil samples.This study applied 4,4'-?dimethylamino?thiodiphenylketone?TMK?was used as the chelating agent.Factors influencing the extraction efficiency of Au and its subsequent determination were studied and optimised.The best conditions were obtained as follows:45?L trichloromethane,0.5 m L ethanol,pH=3,TMK concentration was 0.04 mg·mL-1Quantitative analysis was executed using the internal standard method under optimal conditions:the detection limit was 0.04?g·L-1,RSD was 2.7%3.8%,recoveries were in the range of 96%106%,and enrichment factor was 124 for Au.In addition,the accuracy of the method was verified through reference standard and ICP-MS control experiments and the results indicated no significant differences.Therefore,the developed method was applied to the determination of trace Au in environmental soil samples with satisfactory results.4.A new method based on DLLME and ED-XRF for the preconcentration and determination of Ag in environmental soil samples was developed.Diphenylthiocarbazone was used as the chelating agent in this paper.A series of the influence factors relevant to the microextraction efficiency were optimized.The best conditions were obtained as follows:35?L carbon tetrachloride,0.5 m L ethanol,pH=5,Dithizone concentration was0.03 mg·mL-1.Quantitative analysis was executed using the internal standard method,the recoveries were in the range of 96%108%and the detection limit of 0.05?g·L-1,RSD was 2.5%3.5%and the enrichment factor was 136.The ICP-MS control experiments were conducted simultaneously,and the result were satisfactory,therefore,this method is suitable for detection of trace silver in soil samples.5.A new method based on DLLME and ICP-MS for the preconcentration and simultaneous determination of Au and Pd in environmental soil samples was developed.In this method,1-?2-pyridinylazo?-2-Naohthalenol?PAN?was used as the chelating agent,factors influencing the extraction efficiency and its subsequent determination were studied and optimised.The best conditions were obtained as follows:80?L 1,2-dichlorobenzene,0.7 mL ethanol,pH=4,PAN concentration was 0.09 mg·m L-1.Quantitative analysis was executed using the standard curve method,the recoveries were in the range of 94%105%and the detection limit of 0.005 ng·L-1,the enrichment factor were 143 and 136.So,this method is suitable for simultaneous detection of trace Au and Pd in soil samples. |
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