Abstract
Liquid-liquid microextraction (LPME) is usually applied in extraction of environmental samples. In this thesis, three simple, rapid and low toxicity liquid-liquid microextraction methods have been developed for the extraction and analysis of trace organic compounds in water samples. Dispersive liquid-liquid microextraction (DLLME) was introduced by Rezaee et al. and coworkers. The advantages of DLLME are rapidity, low cost and high enrichment factor. However, the high-toxic extraction solvents used are environment-unfriendly. To solve the aforementioned problems, three extraction methods were introduced in this thesis. The first topic in this thesis describes a DLLME method base on the solidification of a floating organic droplet (DLLME-SFO). This method combined with gas chromatography with electron-capture or mass spectrometry to analyze five halogenated organic compounds (HOCs). The large contact surface between the sample and the droplets of extractants speeds up mass transfer and shorter extraction time. Second topic describes the extraction of organochlorine pesticides (OCPs) in water samples by using DLLME-SFO method. This method used less disperser solvent (200 μL) than the previously reported DLLME-SFO method (500 -1000 μL). The third topic describes the low toxic DLLME (LT-DLLME) using halosolvents for extraction of polycyclic aromatic hydrocarbons in water samples, we compared the extraction efficiency of five chlorosolvents and thirteen bromo/iodo solvents, these halosolvents were applied for the first time in DLLME method. The fourth topic describes the determination of volatile organic compounds (VOCs) in water using ultrasound-assisted emulsification microextraction (USAEME) followed by gas chromatography, this method avoids using the disperser solvent, decreasing the price and the exposure of the operators to toxic extraction solvent. In the first two topics (DLLME-SFO), the floated extractant is solidified and is easily collected for analysis. In addition, this method is no need to use conical bottom glass tubes. The last two topics used high density extraction solvent, less toxicity solvent such as 1-bromo-3-methylbutane and 1-bromooctane to instead of the high toxic solvent which was normally used in DLLME. The results of these four experiments showed that these sample preparation techniques coupled with gas chromatography detection could determinate the trace organic pollutants in the low ppb or ppt level.