| Extraction,clean-up and preconcetration of the analytes are very important procedures in trace analysis of organic pollutants in complex environment and food samples before instrumental analysis.Recently,the development of accurate,rapid,simple,and environmental friendly sample preparation methods is one of the hot points in modern analytical chemistry.Water,as a cheap and environmental acceptable solvent,is suitable for avariety of sample preparation processes,but water extractions without auxiliary energies are very slow and low efficient.Recently,water extraction assisted by high temperature-high pressure,microwave and ultrasound has been reported in preparation of different samples. These methods have the advantages of time saving,high efficiency,high selectivity,simple and environmental friendly,and thus successfully used in separation of analytes from complex samples.Water extraxtion at high temperature-high pressure,i.e.subcritical water extraction,has been widely applied in environmental analysis,but rarely in the rapid detection of food samples.Water has also been used,although in a minor extent,for microwave and ultrasound assisted extractions,the potential of the energies for assisting water extraction surpasses that of the other conventional auxiliary energy sources.Generally,the extractant of the water extraction can not be injected into the instrument directly without further clean-up,enrichment or solvents exchanging.The combination of auxiliary energies assisted water extraction with other green sample preparation processes, such as solvent bar microextraction and molecular imprinting solid-phase extraction,is beneficial to develop a series of rapid,simple,high selectivity and high sensitivity new analytical methods for determination of trace organic pollutants in complex samples.The objective of this dissertation is to develop a series of new green analytical methods based on the water extraction assisted by auxiliary energies such as high temperature-high pressure;microwave and ultrasound combined with other green sample preparation steps and instrument detection techniques for determination of trace organic pollutants in environmental and food samples.The major contents of this dissertation are described as follows:(1) A novel green analytical method for determination of trace chlorobenzenes in soil samples,based on ultrasound-assisted water extraction combined with solvent bar microextraction and high selective and sensitive GC-MS was developed.Compared with traditional methods,such as Soxhlet extraction,ultrasound assisted solvent extraction and shaking extraction,this method is simpler,cheaper,more rapid and friendly for environment.Under the optimized conditions,the method detection limits for 1,2,3-Trichlorobenzene(1,2,3-TCB),1,2,3,4-Tetrachlorobenzene(1,2,3,4-TeCB), Hexachlorobenzen(HCB) and 1-Chloro-4-Nitrobenzene(1-C-4-NB) were 1.3,0.7,27.3 and 1.9μg kg-1,respectively,and recoveries between 93%and 105%with relative standard deviation ranging between 1.56%and 6.29%were achieved from spiked soil samples.(2) A rapid analytical method for the determination of oxytetracycline(OTC), tetracycline(TC) and chloramphenicol(CAP) antibiotics in animal feeds has been developed based on subcritical water extraction(SWE) without further sample clean-up followed by high performance liquid chromatography(HPLC) with ultraviolet(UV) detection.Recoveries between 82.1%and 90.0%with relative standard deviations ranging between 1.6%and 4.8%were achieved from spiked animal feed samples by using this method.Compared with the traditional ultrasonic extraction,this procedure was remarkably more efficient in extracting OTC,TC and CAP,simpler to perform,and there was no use of toxic organic solvents.(3) A high selective and simple analytical method for the determination of chloramphenicol(CAP) in animal feeds has been developed based on subcritical water extraction(SWE),followed by molecularly imprinted solid-phase extraction(SPE) and high performance liquid chromatography(HPLC) with ultraviolet(UV) detection. Molecularly imprinted polymer microspheres(MIPMs) were prepared by precipitation polymerization using CAP as template.The synthetic conditions,kinetics and binding properties of CAP MIPMs were studied.After the evaluation of the selectivity of the CAP imprinted MIPMs,the performance of these materials as SPE sorbents was investigated. Compared with SWE-HPLC method,the SWE-MIPMsSPE-HPLC procedure has higher selectivity and sensitivity,LOD was 0.5μg g-1,as well as better precision(RSD below 6.0 %) and recovery(＞80%).(4) A rapid analytical method for the determination of methomyl pesticide in vegetables has been developed based on subcritical water extraction(SWE) and acetylcholinesterase inhibition assay.The optimum extraction conditions were obtained by using 5mL of water(pH=8) as the extractant at 70℃with 5 min static extraction. Compared with manual shaking extraction,subcritical water extraction has higher extraction efficiency and better precision in determination of spiked and real samples.(5) Two environmental friendly sample preparation methods have been developed based on subcritical water extraction and microwave assisted water extraction respectively for determination of 2-chlorophenol(2-CP),2,4-dichlorophenol(2,4-DCP),4-chlorophenol (4-CP) and pentachlorophenol(PCP) in sediment samples.Sodium hydroxide solution was used as the extractant in these methods.Under the same instrument(GC-μECD) detection conditions,the operating conditions and the analytical characters of SWE and MAWE both are superior to the traditional techniques,such as Soxhlet extraction and microwave-assisted solvent extraction.SWE use electric cooker to heat,which is cheaper, simpler,and more rapid than Soxhlet extraction.MAWE use of specialized equipment, which is more expensive,but the extraction time is very short,the operating conditions are easier to control,and the extraction efficiency especially for low concentrations of chlorophenols(CPs) is higher than other methods.These methods were applied successfully to the analysis of CPs in real sediment samples.
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