| Dispersive liquid-liquid microextraction (DLLME) was a novel and environmental-friendly sample pretreatment technology, which had been proved to be a sensitive, simple, easy to operate technique with high enrichment factor. Dispersive liquid-liquid microextraction (DLLME) was a new extraction mode of LPME, which had some advantages such as rapid, easy to operate and high sensitivity. However, it usually utilized chlorobenzene, carbon tetrachloride or other toxic organic solvents as the dispersive solvents and extraction solvents, and which put potential threat on the environment and operators. Ionic liquid had been considered as green solvent for its special characters such as low vapor pressure, almost no volatility, high stability and the excellent miscibility with inorganic and organic compounds, which made it widely used in many fields. Based on these facts, a novel green sample preconcentration technique named as"temperature-controlled ionic liquid dispersive liquid-liquid microextraction"was designed and developed. This novel technology was successfully completed without toxic organic solvents in the enrichment step, had much higher enrichment. Several methods based on temperature-controlled ionic liquid DLLME were developed for the rapid and sensitive determination of phenols, aromatic amines, PAHs, Atrazine, simazine, cyanazine, bisphenol A, 4-nonylphenol, 4-octylphenol. This thesis is composed of six chapters:In the first chapter, on the basis of a large number of literatures, a review was presented on the application of preconcentraction methods in the analysis of environmental pollutants and the progress of the development and the application of DLLME.In the second chapter, a new method was described for the determination of four phenols based on temperature-controlled ionic liquid dispersive liquid-liquid micro-extraction coupled with HPLC. [C8MIM][PF6] was used as the extraction solvent, the effects of the volume of extraction solvent, pH of working solution, extraction time, dissolved temperature, centrifugation time and salt-out effect were optimized in detail. Under the optimal extraction condition, the experimental results indicated that the linear range, precisions and detection limits of the proposed method were in the range of 1.0-100μg L-1, 2.1-7.2% and 0.27-0.68μg L-1, respectively. The present technique provided lower detection limits, better linear ranges, and lower precisions in comparison with other developed techniques.In the third chapter, the effect of anion in ionic liquid structure on the extraction performance of aromatic amines was investigated in detail. The results demonstrated that the kind of RTIL's anion had a significant impact on the extraction. Under the optimal extraction conditions, the liner ranges were in the range of 1.0-100μg L-1 for 2,4-Dinitroaniline, o-chloroanline, N,N-dimethylaniline and1.5-150μg L-1 for the other two analytes, and the detection limits were in the range of 0.39-0.63μg L-1, and the spiked recoveries of realworld samples were in the range of 92.2-119.3%.In the fourth chapter, the effect of the different alkyl and alkyl length in ionic liquid on the extraction of analytes was investigated with PAHs as the model pollutants. Factors such as the kind and volume of ionic liquids, pH of working solution, extraction time, dissolved temperature, centrifugation time and salt-out effect were optimized. The results indicated that the effect of the alkyl and alkyl chain length was proved and [C8MIM][PF6] provided the best efficiency for these analytes. The linear ranges were in the range of 0.5-100μg L-1, and detection limits of proposed method were in the range of 0.005-0.88μg L-1, and the spiked recoveries of realworld samples were in the range of 85.0-115%.In the fifth chapter, a new method was established based on temperature-controlled ionic liquid dispersive liquid phase microextraction to determine three triazine herbicides. Under the best extraction conditions, the correlation coeffcient, detection limits of this method were in the range of 0.9938-0.9965 and 0.005-0.06μg L-1, respectively. Satisfactory results were achieved with good spiked recoveries in the range of 85.1-100%.The extraction of bisphenol A, 4-nonylphenol, 4-octylphenol from aqueous samples was investigated in detail in the sixth chapter. The factors that would influence the extraction performance were investigated. Under the optimal conditions, the detection limits were in the range of 0.005-0.06μgL-1. Four real environmental water samples were used to validate the developed method and satisfactory results were achieved with good spiked recoveries in the range of 82.8-114.0%. |
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