Synthesis Of Mesoporous Material SBA-15 And Its Application In Solid Phase Microextraction

Ordered mesoporous materials have received a great deal of attention, as a novel mesoporous material, M41S, was firstly reported by researchers in the Mobil laboratory in the early 1990s, because of their potential applications in catalysis, separation technology, nanoscience, and biomaterials. Compared with microporous materials, mesoporous materials not only have larger surface area (up to 1500 m²/g) and thicker wall between pores, uniform pore size distribution (1.5-30 nm) and huge pore volume, but also they have excellently mechanical and chemical stability. They were widely used as catalysts, sorbents and separation materials in the past decade. Up to now a great variety of functionalized and morphologic mesoporous materials have been developed in order to obtain higher selectivity and special action sites.Solid-phase microextraction (SPME) as a new solvent-free extraction technique in sample preparation appeared in the early 1990s. Because of its advantages of simplicity, rapid extraction and easy quantification, SPME was successfully applied to extracting and concentrating for various analytes in environmental samples (gas, liquid, solid), foodstuff, biological samples and materia medica. SPME could be easily coupled with the apparatus, such as gas chromatography (GC) and high performance liquid chromatography (HPLC). Fiber with coating is the most important part of SPME, the selectivity and the extraction efficiency of the fiber depend considerably on the coating materials. Up to date many experimental coatings have been prepared and investigated for a wide range of applications. The coating materals that were universally used in SPME are various polymer-based coatings, such as polydimethylsiloxane (PDMS) and polyacrylate (PA), which were coated on fused silica fibers. However, specialized materials have been also developed for special demand in SPME.In this dissertation, our effort is to synthesize new functionalized mesoporous materials and use as coating materials in SPME for analysis of environmental samples by high-performance liquid chromatography coupling with SPME technique. The dissertation consists of five parts:In Chapter 1, the state of art in the mesoporous material research in the past decade is reviewed. The review focus on synthesis and application of the mesoporous materials and especially emphasizes their application in separation science and technology, the technology and theory of SPME are introduced in brief. The current state of the SPME technique and the development of fiber coatings in SPME are reviewed.In Chapter 2, a mesoporous molecular sieve, SBA-15, was modified with ethanetriethoxy silane (ETTS). Ethane group was successfully grafted on the surface of SBA-15 mesoporous sieve. A new organic-inorganic hybrid material, C₂H₅-SBA-15, was synthesized and characterized by element analysis and FT-IR.In Chapter 3,γ-glycidoxypropyltrimethoxy silane were used as coupling agents for the synthesis of the hybrid mesoporous CH₂OCHCH₂O(CH₂)₃-SBA-15. The inorganic/organic composite mesoporous materials were characterized by XRD,elemental analysis and FT-IR.In Chapter 4, the hybrid mesoporous C₂H₅-SBA-15 was used as solid-phasemicroextraction (SPME) fiber coating. Pyrene in environment water was extracted and determined by SPME-HPLC using C₂H₅-SBA-15 fiber. The experimental conditions of SPME procedure were optimized for extraction and enrichement of the analyte. The method can be used to determine pyrene in environmental water.In Chapter 5, solid-phase microextraction (SPME) using C₈-SBA-15 coated fiber coupled with high-performance liquid chromatography (HPLC) for the determination of polycyclic aromatic hydrocarbons (PAHs) in water in real world (Yellow river water) was reported. Three PAHs (anthrance,naphthalane,fluorene) were studied with the C₈-SBA-15 fiber. The experimental conditions of SPME, such as extraction and desorption time, extraction temperature, salt concenation and agitation were studied and optimized. At the same time, SBA-15 coating has higher extraction capacity and sensitivity, better reproducibility and selectivity than bonded porous silica coating...