Application On Trace Analysis For Environmental And Biological Samples Based On Novel Dispersive Liquid-Liquid Microextraction Technique

Dispersive liquid-liquid microextraction(DLLME), an alternative mode of liquid phase microextraction(LPME), which shows remarkable attributes of simplicity, rapidity and high efficiency, has arisen much attention in analytical chemistry in recent years. With the rapid development of its agents in the extraction, the decentralized approach and the technical aspects combined, DLLME has been widely used for the analysis of different objects and different media samples. Some related work have been done in this article from the extraction agent and application of existing methods, which aimed at broadening the choice of extractant and expanding the scope of application of existing methods, developing more effective method for real sample analysis.The major contents were summarized as follows.1. A method of the ultrasound-assisted dispersive liquid-liquid microextraction with ionic liquid [C6mim][PF6] as extractant for the preconcentration of malachite green in fish and water samples was developed. Under the optimum conditions, the detection limit of MG as low as 0.005 ng mL-1 was obtained, while the relative standard deviation for three replication determination of 0.5 ng mL-1 was 8.9%. Enrichment factor can reach 220. The proposed method was applied successfully to the determination of MG in several samples. Compared with the traditional DLLME, this method presents a lower detection limit, shorter extraction time and less solvent.2. A new method of temperature controlled [Allylmim][PF6]-based dispersive liquid-liquid microextraction with HPLC for the determination of 2-chlorophenol, p-chlorophenol,4-tert-butylphenol, bisphenol A in water samples was established. Under the optimum conditions, the detection limit of phenols was in the range of 0.55-1.7 ng mL-1 and relative standard deviation for three replication determination of 100 ng mL-1 was 2.2-5.4%. The proposed method was applied to the determination of phenols in Mineral water and the recoveries of spiked samples were in the range of 92.3-102.7%. Compared with the traditional TCIL-DLLME, the separation of two Phases became much easier in this method.3. A new method was developed for the determination of PAHs in water samples using low-density extraction solvent-based solvent terminated dispersive liquid-liquid microextraction(ST-DLLME) followed by gas chromatography. Under the optimum conditions, the detection limit of PAHs was in the range of 0.52-5.11 ng mL-1. The proposed method was successfully applied to the determination of PAHs in environmental water samples and the recoveries of spiked samples were in the range of 80.2-115.1%. Compared with the traditional DLLME, this method offered significant advantages of simple operating and time saving.4 A simple and fast method of solvent terminated dispersive liquid-liquid microextraction(ST-DLLME) was developed for the determination of methyl parathion (MP) in the water samples by high performance liquid chromatography(HPLC). Under the optimized conditions, the limit of detection of the method was 0.03 ng mL-1 and the precision(RSD) was 3.3% for the determination of 10 ng mL-1 MP(n=3). The proposed method was applied to the determination of MP in Yangtze River, East Lake and tap water samples with satisfied results. Comparing with traditional DLLME, it offered significant advantages of simple operating and taime saving (no centrifugation). And it is expected to be used for the situ treatment of methyl parathion in field and shows a good prospect in the rapid detection of trace residues of pesticides.