CHEMICALLY MODIFIED SILICA AS BONDED PHASE SUBSTRATE FOR CHROMATOGRAPHY

拟议项目的主要目标是推进 通过增强的现代色谱方法的能力 了解硅烷化固定相表面结构和 随后开发了改进的键合相材料。 进展 生物医学研究与选择性和敏感性密切相关 由于化学复杂性而导致色谱方法的局限性 生物基质以及样品分离之前的必要性 分析。 开发具有改进色谱的支持材料 性能需要对固定相表面有清晰的了解 结构和有问题的表面物种的存在。研究 本提案中描述的内容最终将有助于 了解未改性和硅烷化二氧化硅的表面结构 将促进键合相性能的未来进步 支持。 研究的具体目标是： 1）研究 热处理对变孔多孔硅胶的影响 直径，2) 研究表面甲硅烷基化的程度及其发生方式 受不同试剂（烷氧基、氯代和有机氨基硅烷）的影响， 孔径、硅烷烷基链长、胺催化剂、表面 吸附水等，3）比较研究动力学 使用溶液和气态硅烷试剂进行硅烷化反应 阶段。 将完成改性表面的表征 使用变温漫反射 FTIR 光谱 (VT- DRIFTS）与可加热、可抽空样品室结合使用。 DRIFTS 的分析将确保表面物种完好无损 不因样品制备程序而改变。 样品室的使用 将允许进行原位环境控制研究，其中探针 分子可以与表面位点相互作用。 表征研究将 阐明附着物的结构性质和表面浓度 硅烷，以及结构性质、浓度和相对 表面硅烷醇 (SiOH) 物质的酸性。

The primary objective of the proposed project is to advance the capabilities of modern chromatographic methods through an enhanced understanding of silylated stationary phase surface structure and the subsequent development of improved bonded phase materials. Advances in biomedical research are closely tied to the selectivity and sensitivity limitations of chromatographic methods because of the chemical complexity of biological matrices and the necessity for sample separation prior to analysis. Developing support materials with improved chromatographic performance requires a clear understanding of stationary phase surface structure and the existence of problematic surface species. The research described in this proposal will ultimately contribute to the understanding of unmodified and silylated silica surface structure which will facilitate future advances in the performance of bonded phase supports. Specific goals of the research will be; 1) to study the effects of thermal treatment on porous silica gels having variable pore diameter, 2) to study the extent of surface silylation and how it is affected by different reagents (alkoxy, chloro, and organoaminosilanes), pore diameter, silane alkyl chain length, amine catalysts, surface adsorbed water, etc., and 3) to comparatively study the kinetics of the silylation reaction using silane reagents in both solution and gaseous phases. Characterization of the modified surfaces will be accomplished using variable-temperature diffuse reflectance FTIR spectroscopy (VT- DRIFTS) in conjunction with a heatable-evacuable sample chamber. Analysis by DRIFTS will insure that surface species are intact and unaltered by the sample preparation procedure. Use of the sample chamber will allow for in-situ environmentally controlled studies whereby probe molecules can interact with surface sites. Characterization studies will elucidate the structural nature and surface concentration of attached silanes, as well as the structural nature, concentration and relative acidity of surface silanol (SiOH) species.