| Pretreatment technology plays an important part in analyzing organic pollutants. It has direct effect on the accuracy of the result. In order to overcome the disadvantage of tedious workup, large amounts of toxic organic solvent usage in the classical LLE extraction of environmental organic pollutants, at present many novel methods have been put forward, such as Solid Phase Extraction (SPE), Solid Phase Microextraction (SPME), Membrane Extraction (ME), Microwave Assisted Extraction (MAE), Accelerated solvent extraction (ASE), Liquid Phase Microextraction (LPME), et al. These methods are little organic solvent required, fast and easy to be auto-operated, so called as green pretreatment technology. This thesis make systematic researched in the aspect of Liquid phase microextraction.Liquid phase microextraction (LPME) is developed as a novel solvent-minimized pretreatment technique. With inexpensive apparatus, LPME virtually eliminates solvent consuming, and combines extraction, preconcentration and sample introduction in one step. This technique combined with gas chromatography (GC) or gas chromatography-mass spectrum (GC-MS), high performance liquid chromatography (HPLC) and capillary electrophoresis (CE) is primarily applied for the analysis of non-volatile and fixed environmental contaminations and drugs of low concentration in biological samples.1. Single drop microextraction coupled with gas chromatography was developed for the determination of Phthalic esters in water. Extraction solvent, extraction time and stirred speed were optimized. Optimal experimental conditions were as follows: 2μL toluene microdrop exposed for 20min in a 3mL aqueous sample placed in 4mL vial and stirred at 600rpm/min. The concentrated factor of dimethyl phthalate and dibutyl phthalate ranged between 228 and 318. The RSD of the proposed method varied between 9.4% and 6.4%. The limits of detection were 1.4μg/L and 0.8μg/L, respectively. The recoveries for surface water, wastewater and seawater were in range of 94.5%~99.3% for DMP and 87.0%~102% for DBP. Due to predigest the pretreatment, which can overcome the problem of the blank contaminations when analysis Phthalic esters, the method with little solvent consumption was simple, fast, sensitive and suitable for the determination of Phthalic esters in clean water, waste water and seawater.2. A novel method for the determination of Phthalic esters in water samples has been developed using Dynamic-Liquid phase microextraction and gas chromatography, with the influential factors in experiment optimized. The developed method was found to yield a linear calibration curve in the concentration ranging from 0.2~1.5mg/L for the target analytes and the limits of detection were in the lowμg/L level, ranging between 4.5 and 17.6μg/L. The recoveries were 70.2%~87.5%. Good repeatability of extraction was obtained, with the RSD values between 4.7% and 8.6%, respectively. The method has been used to determine Phthalic esters in drinking water and seawater sample.3. Single drop microextraction, followed by gas chromatography with flame ionization detection (GC-FID) has been applied to determine Formaldehyde, Acetaldehyde and Acraldehyde in water based on 2,4-Dinitrophenylhydrazine derivatization. Extraction solvent, extraction time and stirrer speed were optimized. Optimal experimental conditions were as follows: 1.6μL toluene microdrop exposed for 30 min in a 3ml aqueous sample placed in 4ml vial and stirred at 600 rpm/min. The Concentraction factors of Formaldehyde, Acetaldehyde and Acraldehyde were 305, 356 and 261. The repeatability of the proposed method, expressed as relative standard deviation was 7.1%, 5.2% and 8.9%. And the limits of detection was 1.4μg/L,1.3μg/ and 3.1μg/L.
|
PDF Full Text Request