| In the determination of organic pollutants in soil samples, sample preparation is veryimportant, because the matrix is complicated and concentration of analyte is very low. It isimportant to develop fast, efficient, simple and green sample preparation method in orderto obtain reliable, repeatable analytical result.Dispersive liquid liquid microextraction(DLLME), which is a new mode of liquidphase microextraction, was proposed recently. In this method, the appropriate extractionsolvent and dispersant was injected into the aqueous sample rapidly with syringe, followedby oscillation, ultrasoud or microwave extraction. The extraction solvent was dispersedinto the aqueous sample as very fine droplets and the analytes were easily and fasttransferred to the extraction solvent. When extraction equilibrium was obtained, phaseseparation was performed by centrifugation, and the enriched analytes in the sedimentphase were determined by chromatographic methods. In this method, extraction,enrichment and separation were carried out at the same time. The advantages of theDLLME are simple, rapid, enviromental friendly, inexpensive and highly efficient. Theapplication of DLLME in trace analysis is wide.Accelerated solvent extraction is a new solvent extraction method, and can be appliedto the treatment of a solid or semi-solid samples. The extraction efficiency and extractionspeed are improved by improving the extraction temperature and pressure. The solutbiltyand diffusion rate increased with the elevated temperature and pressure, so the efficiencyof extraction. The method has some advantages, such as low envriomental pollution, lowexpenditure of organic solvent, rapidity, high recovery and automation.The room temperature ionic liquids (RTILs) are promising green solvents and were applied to the extraction and separation. The RTIL has some unique chemical and physicalproperties, such as nonvolatility, good thermal stability, superior solutility and tunableproperties. The extraction should be enviromental friendly because volatile organicsolvents are replaced by RTIL.In this thesis, soil was taken as analytical sample. The pesticides and phthalic acidesters were extracted and determined by accelerated solvent extraction-liquidchromatography tadem mass spectrometry and ionic liquid microextraction-liquidchromatography.The microwave-assisted homogeneous ionic liquid microextraction (MA-HILME)coupled with high-performance liquid chromatogrophy, was developed for determinationof dimethomorph, mefenacet, isoprothiolane, oxadiazon. Some experimental parameters,such as type of IL, microwave power, microwave time, sample amount, IL volume,ionic-pairing agent amount, time of centrifugation were examined. The recoveries from74.2～97.9%were obtained for three samples at fortification levels (35ng·g-1and140ng·g-1) with relative standard deviations (RSDs)≤5.97%. Compared with ultrasonic andSoxhlet extraction, there is little difference in recoveries obtained by the three methods,only a small amount of IL(0.10mL) was used in the present method. The extraction timeof the present method(16min) was shorter than those of UE(40min) and SE(240min).The present method was a comparatively satisfactory method.A rapid and accurate method based on accelerated solvent extraction liquidchromatography tandem mass spectrometry(LC-MS/MS) was developed for thedetermination of carbofuran, dimethomorph, mefenacet, isoprothiolane, acetochlor,pretilachlor, uizalofop, oxadiazon and fenpropathrin in soil. Some experimentalparameters, such as extraction solvent, extraction temperature, cycle number, static time,flush volume, purging time, were examined and optimized. The analytes were extracted byaccelerated solvent extraction using acetonitrile as the extraction solvent. The recoveriesfrom90.0～105.0%were obtained for five samples at fortification levels (10ng·g-1and100ng·g-1) with relative standard deviations (RSDs)in1.0～5.9%. Compared withoscillating and Soxhlet extraction, this method is more rapid and suitable to the extractionof pesticides in soil.The determination of11phthalic acid esters(PAEs) in soil sample by acceleratedsolvent extraction coupled with liquid chromatography tandem mass sepctrometricdetection was described. The1.0g sample was used. n-Hexane was used as the extractionsolvent. The extraction conditions, such as extraction temperature, cycle number, staticVI time, flush volume, purging time were160℃,4,12min,60%,90s, respctively. Thismethod is rapid, sensitive and suitable to the determination of PAEs in soil. Theorthogonal test was preformed and the results match the results obtained by single factorexperiment. The range analysis indicated that the extraction temperature was the maininfluence factor. The recoveries of11phthalic acid esters were between72.8～101.8%,with relative standard deviations (RSDs) between1.7～6.7%. Compared with Soxhletand ultrasonic extraction, higher recovery and lower limit of detection were obtained bythis method.The ultrasound-assisted ionic liquid microextraction coupled with high-performanceliquid chromatographic detection, has been developed for determination of sulfonylureaherbicides. The key parameters, such as type of IL, volume of IL, amount of sample,ultrasonic power and time, were examined and optimized. The Recoveries of nicosulfuron,metsulfuron-methyl, bensulfuron-methyl, pyrazosulfuron-ethyl are94.1～99.4%(RSD≤6.32%）,81.1～92.2%(RSD≤5.41%),81.3～90.6%(RSD≤3.61%),93.6～100.1%(RSD≤7.44%) and the limits of detection are10.2,11.3,8.5and7.7ng·g-1, respectively.The intra-day and inter-day RSD are lower than7.56%and7.93%, respectively.Compared with Soxhlet and ultrasonic extraction, the present method is easier operated,more rapid and enviromental friendly. |
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