| In recent years, the development and application of nano-materials has become a hot subject. Carbon nanotubes (CNTs) and TiO2 nanotubes are novel kinds of nano-materials. Carbon nanotubes have not only special structure but also mechanical properties, electric characteristics, chemical quality and large specific area. Hence, CNTs have drawn much more attention and have been applied in many scientific and research domains. Published reports indicated that CNTs had a strong adsorption for many environmental organic pollutants such as the triazine herbicide, the sulfonylurea herbicide and DDT in environment and so on. Based on these facts, it is believed that CNTs may have great potential as solid phase extraction adsorbent in determining the pesticide residues at trace level. TiO2 nanotubes have larger specific area and more excellent adsorption ability, and it has great potential in many areas including environmental purification, gas sensors, photovoltaics, photocatalytic degradation of organic pollutants in air and water. But the application of TiO2 nanotubes in the analysis of environmental samples has not been reported. Therefore this thesis focused on the application of CNTs and TiO2 nanotubes as solid phase extraction adsorbents.1. A brief review was presented focused on the application of CNTs in pesticide residues and the foreground of CNTs application.2. Multi-walled carbon nanotubes (MWCNTs) as solid-phase extraction adsorbents coupled with HPLC for the extraction of thiamethoxam, imidacloprid and acetamiprid was investigated. Several factors such as the kind and volume of eluent, the flow rate, pH and volume of sample solution, which may influence the extraction efficiency of MWCNTs were optimized. The linear range was in the range of 0.08-100μg L-1 for the target compounds, and precision was excellent in the scope of 0.7-1.1% (RSD). Detection limits were in the range of 5.4-6.7ng L-1. Finally, the established method was used for the analysis of the real environmental water samples. It was shown that the spiked recoveries of three analytes were in the range of 87.5-109.8%.3. The enriching performance of MWCNTs for preconcentrating the cyanazine, chlorotoluron and chlorbenzuron was investigated in detail. Factors that may influnce the extraction efficiency were optimized and the optimal conditions were obtained. Solid-phase extraction coupled with high-performance liquid chromatography was applied to the analysis of the three targets. Under the optimal condition, the detection limits of cyanazine, chlorotoluron and chlorbenzuron were 15ngL-1, 12 ngL-1, 34 ngL-1 respectively, the relative standard deviation of the method were 0.38-3.54% for the three compounds. The established method was employed to determine the objective compounds in several environmental water samples such as tap water, ground water, snow water and sewage water. Satisfactory results were achieved with good spiked recoveries in the range 87.8-110.1%. The adsorption efficiency of MWCNTs and C18 was compared in the experiment, and the results indicated that MWCNTs showed the comparable adsorption efficiency and more excellent adsorption efficiency for chlorbenzuron with C18.4. MWCNTs as solid-phase extraction adsorbents coupled with HPLC for the determination of metalaxyl, diethofencarb, myclobutanil, prometryn and tebuconazole were investigated. Under the optimal conditions, the detection limits were 3.0 ng L-1, 3.7 ng L-1, 4.1 ng L-1, 0.8 ng L-1, and 6.9 ng L-1, respectively, and the relative standrad deviations were 1.43-5.86%. Finally, satisfactory results were achieved from the analysis for the environmental water samples such as tap water, ground water, rain water and reservior water.5. DDT and its main degradation products including o,p'-DDT, p,p'-DDD, p,p'-DDE, p,p'-DDT were chosen as target compounds in order to study the applied potential of TiO2 nanotubes as solid phase extraction adsorbent. Factors that may influnce the extraction efficiency were optimized and the optimal enrichment conditions were obtained. The experimental results indicated that the linear ranges were 0.5-20μg L-1, the precisions were 1.6-7.4%, and detection limits were in the range of 2.50-5.34ng L-1. Good results were achieved from the analysis of environmental water samples.6. A summary was presented on the application of MWCNTs and TiO2 nanotubes as SPE addorbents in the analysis of organic pollutants in environment and the direction for future research.
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