| Extraction and enrichment of trace pollutants from soil is a hot issue in environment sample preparation. It brings great difficulties to soil analysis because of the wide range of concentration and the varieties of interruption in soil matrix. Matrix solid-phase dispersion extraction integrates extraction, filtration and clean-up into a single step. It is widely used in contaminants analysis from solid and semi-solid samples. However, there were two drawbacks: Firstly, the complete manual operation lead to inefficiency. Secondly, low sensitivity caused by less amount consumption of samples. In this thesis, the two defects were improved. A method using ball milling based matrix solid-phase dispersion extraction- dispersed liquid phase microextraction- gas chromatography-mass spectrometric has been developed for the determination of pyrethroids and phthalates in soil respectively. The primary coverage of this thesis as follows:(1) With the improvement of grinding method, a ball-milling based matrix solid-phase dispersion extraction was developed, in order to instead of grinding by hand. The grinding effect and time consumption of pretreatment was compared by employing manual grinding and ball milling respectively. Subsequently, a hypothesis test was applied to analyze the difference in the extraction of pyrethroids and phthalates from soil sample. Finally, the results showed that manual grinding could be replaced by ball milling.(2) A ball-milling based matrix solid-phase dispersion extraction- dispersed liquid phase microextraction- gas chromatography mass spectrometry method has been developed for the determination of three pyrethroids(tetramethrin, permethrin and deltamethrin) in soil. Several conditions were optimized. The best conditions as follows: 0.5 g soil and 1.5 g C18 solid phase extraction powder was grinding for 5 min. The mixture was eluted with 10 m L of acetone. The eluent was concentrated to 0.4 mL, and then mixed with 20 μL of tetrachloromethane and 5.0 mL of ultrapure water to form a homogeneous cloudy solution. The emulsion was broken by centrifugation. 1 μL sediment was injected and analyzed directly by GC-MS. Good linearities for three pyrethroids were ranged of 5 ~ 200 μg/kg(r≥0.9994), and recoveries at three spiked levels were ranged of 86.5% ~ 108% with RSD less than 7.8%(n=6). The LODs of three pyrethroids were 1.00~1.48 μg/kg.(3) A ball-milling matrix solid-phase dispersion extraction- dispersed liquid phase microextraction- gas chromatography mass spectrometry method has been developed for the determination of five phthalic acid esters(DMP, DEP, DBP, BBP, DNOP) in soil. Several conditions were optimized. The best conditions as follows: 0.2 g soil and 0.4 g Florisil was grinding for 8 min. The mixture was eluted with 10 mL of acetone- ethyl acetate(1:1, V:V). The eluent was dried by nitrogen and resolved by 0.4 m L acetonitrile, then mixed with 30 μL of tetrachloromethane and 5.0 mL of ultrapure water to form a homogeneous cloudy solution. The emulsion was broken by centrifugation. 1 μL sediment phase was injected and analyzed directly by GC-MS. Linearities of the five PAEs was good from 25 to 500 μg/kg for DMP, from 10 to 500 μg/kg for DEP, from 5 to 500 μg/kg for DBP, BBP and DNOP. The correlation coefficients ranged from 0.9991 to 0.9999, and average recoveries at two spiked levels were ranged of 85.5% ~ 104% with RSD less than 8.2%(n=5). The LODs of five PAEs were ranged of 0.32~2.90 μg/kg. This method is rapid, and simple, can meet the determination of trace PAEs in soil. |
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