| Dispersive liquid-liquid microextraction (DLLME) was a novel liquid microextraction technology, which had some advantages such as simplity, rapidness, low consumption of organic solvent, low cost, high sensitivity, revovery and stability. Compared with liquid-liquid extraction, solid extraction and solid phase microextraction, DLLME has its own special advantages. For the sake of reduction of secondary pollution and improvement of the sensitivity, several methods based on DLLME were developed for the rapid and sensitive determination of atrazine, simazine, aromatic amines, DDT and its main metabolites, and carbamate pesticides.Chapter One, a review was presented on the application of DLLME in the analysis of environmental pollutants.Chapter Two, a new method based on DLLME was developed for the determination of atrazine and simazine. The parameters such as the type and volume of extraction solvent, the type and volume of dispersive solvent, sample pH, extraction time, centrifugation time and salt-out effect were optimized. The results showed that the optimal extraction condition was as followed, extraction solvent, 60μL carbon tetrachloride; dispersive solvent, 550μL acetonitrile; sample pH, pH 5; extraction time, 5min; centrifugation time, 2min; addition of NaCl,10% (w/v). The experimental results indicated that the linear ranges were in the range of 0.1-50μgL-1, and the limits of detection were 0.601μgL-1 and 1.550μgL-1, respectively. Precisions were 6.4% and 4.6%, respectively. The proposed method was validated with real-world samples and the spiked recoveries were in the range of 60.7%-91.4%.Chapter Three, a novel, rapid, and sensitive method for the analysis of aromatic amines was established. The optimal extraction conditions were as followed, extraction solvent, 60μL chlorobenzene; dispersive solvent, 500μL acetonitrile; sample pH, pH 12; extraction time, 2min; centrifugation time, 4min. The linear ranges were in the range of 1-50μgL-1, and the detection limits of proposed method were in the range of 0.1-0.7μg L-1. The precisions were in the range of 6.3%-9.7%. And the spiked recoveries of realworld samples were in the range of 92.8%-111.5%.Chapter Four, a new method was established based on DLLME for the determination of DDT and its main metabolites. The experimental results showed that the optimal extraction conditions were as followed, extraction solvent, 50μL carbon tetrachloride; dispersive solvent, 600μL acetonitrile; sample pH, pH 7, extraction time, 2min; centrifugation time, 6min. The linear range of the proposed method was in the range of 1-50μgL-1, and the limits of detection were in the range of 0.32-0.51μgL-1. The precisions were in the range of 2.80%-7.50%. This method was applied to the analysis of the real water samples and satisfactory results with spike recoveries in the range of 85.6%-119.6% were obtained.Chapter Five, a new concept using ionic liquid as the extraction solvent was optioned for the development of determination method of carbamate pesticides based the principle of DLLME in order to reduce the consumption of toxic organic solvent. The experimental results demonstrated that the established temperature controlled ionic liquid dispersive liquid liquid microextraction method was very simple rapid, sensitive, and easy to operate. The optimal extraction conditions were as below, extraction solvent, 40μL [C6MIM][PF6] ; sample pH, pH 6; extraction time, 30min; centrifugation time, 15min; extraction temperature, 70℃; addition of NaCl,15%(w/v). The linear ranges, precisions and the detection limit were 3.1-1000μg L-1, 1.04%-1.76%, and 0.45-1.40μg L-1. The method was validated with real water samples and the spiked recoveries were in the range of 82.6%-108.7%. |
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