CHEMICALLY MODIFIED SILICA AS BONDED PHASE SUBSTRATE FOR CHROMATOGRAPHY

拟议项目的主要目标是促进 现代色谱方法的能力，通过增强 了解硅烷化固定相表面结构和 随后开发改进的粘结相材料。 进展 生物医学研究与选择性和灵敏度密切相关 由于化学复杂性，色谱方法的局限性 生物基质和样品分离之前的必要性， 分析. 用改进的色谱法开发支持材料 性能要求清楚地了解固定相表面 结构和有问题的表面物种的存在。研究 本提案中所述将最终有助于 了解未改性和硅烷化的二氧化硅表面结构， 将促进未来的进步，在性能的保税阶段 支持. 研究的具体目标是：1）研究 热处理对可变孔径多孔硅胶的影响 直径，2）研究表面硅烷化的程度和它是如何 受不同试剂（烷氧基、氯和有机氨基硅烷）的影响， 孔径，硅烷链长，胺催化剂，表面 吸附水等，3）比较研究了 在溶液和气体中使用硅烷试剂的硅烷化反应 阶段。 将完成改性表面的表征 使用变温漫反射FTIR光谱（VT- DRIFTS）与可加热抽真空的样品室相结合。 DRIFTS分析将确保表面物种完整， 不受样品制备程序的影响。 样品室的使用 将允许进行现场环境控制研究，从而进行探测 分子可以与表面位点相互作用。 表征研究将 阐明附着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）物种的酸性。

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.