The Application Study On The Analysis Of Persistent Organic Pollutants By Capillary Microextraction

Persistent organic pollutants（POPs）are of great concern because of their environmental persistence,bioenrichment,long-distance migration capacity,negative effects on the regional and global environment,and toxicity.The analysis methods,environmental behavior and ecological risk assessment of POPs have become an important hot topic in the field of environmental science in the past decade.However,environmental samples have various forms and complex substrates,and POPs are at trace level in the environment,and there are many homologues and serious interference.Therefore,efficient and selective sample pretreatment has become an important link and technical bottleneck in analysis and determination of POPs.At present,a variety of environmental sample preparation technology including liquid-liquid extraction（LLE）,solid-phase extraction（SPE）,dispersive solid-phase extraction（DSPE）,solid-phase microextraction（SPME）and microwave assisted extraction（MAE）have been developed to separate and enrich the trace POP.However,there are some disadvantages of those methods during the process of real environmental sample detection,such as time-consuming and labor-intensive,large consumption of organic solvents,and harmful to human health,etc.Capillary microextraction（CME）was a new technology of the solid phase microextraction,which had been widely used in separation science because of its simple operation and low consumption of organic solvents,and easy automation.In addition,the monolithic column contains both mesopores and microporous structures,which can make it process good permeability,fast mass transfer,and rapid separation.Combining monolithic columns with in-tube solid-phase micro-extraction technology can make better use of their advantages.Therefore,it is of great significance to prepare monolithic columns with high efficiency,good selectivity and strong mechanical stability.In this thesis,a new capillary monolithic column extraction material was prepared for CME.Combined with high performance liquid chromatography（HPLC）,a new method for the analysis of POPs was established.A new type of capillary monolithic column extraction material was studied and prepared for CME.The research content of this thesis is as follows（divided into four chapters）:Chapter 1:First,the classification and preparation methods of capillary monolithic columns are introduced.Secondly,the capillary microextraction（CME）and its application in the adsorption and separation of environmental organic pollutants are reviewed.Finally,the preparation of organic-inorganic hybrid monolithic columns and organic polymer monolithic columns and their applications in environmental analytical chemistry are systematically summarizedChapter 2:A simple sol-gel method（one-step method）was used to prepare a new type of organic-inorganic hybrid monolithic column doped with imidazole framework of flower-like zeolite.Fourier infrared spectroscopy（FT-IR）,scanning electron microscope（SEM）,X-ray photoelectron,spectroscopy（XPS）and N₂ adsorption-desorption were used to characterize it.The result proved that the monolithic column was well connected to the tube wall and exhibited continuous uniform porous structure.In addition,abundant macroporous and mesoporous channels are conducive to rapid mass transfer and efficient adsorption.The Orthogonal array design（OAD）was used to optimize the CME extraction conditions.Under the optimal conditions,the proposed method showed lower detection limit(0.52μg L^-1)and a wide linear range(1μg L^-1-500μg L^-1),good recovery rate（88.4%-114%）and low relative standard deviation（RSD）<1.4%for four BFRs.Chapter 3:A poly-（AGE-MMA-EDMA）organic polymer monolithic column was prepared through the simple organic polymerization between allyl glycidyl ether（AGE）and methyl methacrylate（MMA）in the quartz capillary modified by 3-（methacryloxy）propyltrimethoxysilane（KH-570）.It was characterized by FT-IR,SEM and N₂adsorption-desorption.The results showed that the monolithic column was tightly integrated with the tube wall,and possessed uniform morphology,stable structure and good permeability.The polycyclic aromatic hydrocarbons（PAHs）in three real water samples were analyzed by CME combined with HPLC.The Orthogonal array design（OAD）was designed to optimize the CME conditions.Under the optimal conditions,the monolithic housing exhibited excellent adsorption performance and efficient enrichment capacity for PAHs due to the hydrophobic effect and theπ-πconjugation effect.This method has the advantages of high selectivity,strong resistance to matrix interference,and small sample volume required,and it is suitable for the analysis and determination of trace PAHs in trace samples with complex matrix.Chapter 4:A poly-（AGE-Styrene-EDMA）organic polymer monolithic column was prepared through the simple organic polymerization between allyl glycidyl ether（AGE）and Styrene in the quartz capillary modified by 3-（methacryloxy）propyltrimethoxysilane（KH-570）.It was characterized by FT-IR,SEM and N₂ adsorption-desorption.The results showed that the monolithic column was tightly integrated with the tube wall and possessed uniform internal structure.Eight PAHs in environmental water samples were detected and analyzed by the CME combined with HPLC,the results showed that the proposed method exhibited lower detection limit(0.05μg L^-1),wider linear range(0.1μg L^-1-200μg L^-1),and good recovery rate.