| Along with the social development and industrial progress, more and more environmental problems appear in our life, control of environmental pollution has been paid widespread attention by everybody. However, the concentration level of the toxic contaminants in the complex matrix is trace and the chemical compositions are rather complicated, which is very difficult to directly determine the real concentration of the target compounds. The sample preparation steps include separation, enrichment and purification of the targets from the studied matrix, which is very important for quantitative analysis. In some sense, the reliability of the analytical method depends on the quality of the sample pretreatment procedures.Most of traditional sample pretreatment techniques are tedious, time-consuming and consume large amounts of toxic and hazardous organic solvents, which can cause secondary pollution to the environment. Therefore, it is necessary to develop simple, rapid, efficient and green sample pretreatment techniques. To solve these problems, two graphene mesoporous composite materials have been synthesized and they were makes as adsorption material and applied to dispersed solid phase extraction(DSPE) and solid phase microextraction(SPME) for determination of phenols and brominated flame retardants(BFRs).The thesis consists of four parts:In Chapter 1, the applications of novel sample preparation techniques have been summarized, such as SPE and SPME in the environmental analysis. The mesoporous materials, graphene composite material and its application have been introduced.In Chapter 2, graphene aerogels(GAs) was prepared by convenient one-step hydrothermal, then graphene aerogels–mesoporous silica(GAs–MS) and graphene aerogels–mesoporous carbon(GAs–MC) were successfully synthetized. Samples were characterized by X-ray diffraction(XRD), Transmission electron micrography(TEM), Scanning electron micrography(SEM), N2 adsorption-desorption. The two kind of mesoporous materials have large specific surface area and highly ordered mesoporous structure, can be used as adsorption material and been applied to environmental analysis.In Chapter 3, the GAs–MS was used as a promising adsorbent for the removal of hazardous phenols from wastewater. The durability and adsorption kinetics, thermodynamic characteristics of GAs–MS were evaluated. On the basis of adsorption experiments, GAs–MS showed superior capability for removal of phenols from wastewater compared with commercial activated carbon.In Chapter 4, GAs–MC was used for the first time as fiber-coating materials for SPME. The fiber was prepared using stainless steel wire as the supporting core and immobilized by epoxy-resin. The main parameters that affect the extraction and desorption efficiencies, such as extraction temperature, extraction time, desorption time, stirring rate and ionic strength of samples were optimized. The optimized SPME coupled with High-Performance Liquid Chromatography(HPLC) was successfully applied to the determination of BFRs in water samples. On the other hand, the commercial extraction fibers were compared with home-made fiber and the sensitivity and accuracy of the method were investigated. The results show that the homemade fiber has good extraction performance to the target analyte, and the linearity was from 10.0 to 1000 ?g L-1for each compound except TBBPA-hee(from 20 to 1000 ?g L-1), limits of detection were between 0.2-0.9?g L-1(S/N=3). The analytical results of real water samples showed that the recovery ranged from 74.6% to 96.2% with relative standard deviation from 3.0% to 8.7%. The fiber coating is sensitive, accurate and suitable for the preconcentration and determination of BFRs in real water samples... |
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