Microscopic Probing of Silica Surfaces

二氧化硅表面的显微探测

• 批准号: 9610446
• 负责人: Mary Wirth
• 金额: $ 43.38万
• 依托单位: University of Delaware
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-03-15 至 2000-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9610446&HistoricalAwards=false
• 关键词: Microscopic; Probing; Silica; Surfaces

In this project, Mary J. Wirth of the University of Delaware is supported by a renewal grant in the Analytical and Surface Chemistry Program. She will study the adsorption of organic cations to silica-based chromatographic surfaces in order to understand the physical phenomena responsible for zone tailing in chromatographic separations which is a long-standing problem hindering separation of a large number of important compounds such as proteins and pharmaceuticals. Atomic force microscopy will be used to measure surface charge density over a wide pH range. Single-molecule detection of an organic cation, rhodamine 123, will be used to probe lateral diffusion and desorption rates as a function of surface charge density, which is controlled by pH. Stationary phases will be synthesized with varying silanol concentration, monolayer coverage and monolayer hydrophobicity, along with horizontally polymerized monlayers to reduce surface charge density. Adsoption isotherms will be generated from data obtained by elution of rhodamine 123 on nonporous silica gel and tested by performing the single-molecule and atomic force microscopy experiments on the same material. In this work, physical and chemical factors responsible for the currently inefficient chromatography of important classes of compounds such as pharmaceuticals and proteins will be investigated. The experiments to be done are multidisciplinary in nature, bringing together ideas from optical spectroscopy, self-assembled monolayer research, scanning probe microscopy and chemical separations. The practical impact of the work will result in faster more complete separations for analysis and preparative purposes.

在该项目中，特拉华大学的 Mary J. Wirth 得到了分析和表面化学项目续期拨款的支持。 她将研究有机阳离子对二氧化硅色谱表面的吸附，以了解色谱分离中区域拖尾的物理现象，这是阻碍蛋白质和药物等大量重要化合物分离的长期存在的问题。 原子力显微镜将用于测量较宽 pH 范围内的表面电荷密度。 有机阳离子罗丹明 123 的单分子检测将用于探测横向扩散和解吸速率与表面电荷密度的关系，表面电荷密度由 pH 控制。 将合成具有不同硅烷醇浓度、单层覆盖度和单层疏水性的固定相，以及水平聚合单层以降低表面电荷密度。 吸附等温线将通过在无孔硅胶上洗脱罗丹明 123 获得的数据生成，并通过在相同材料上进行单分子和原子力显微镜实验进行测试。 在这项工作中，将研究导致目前药物和蛋白质等重要化合物色谱分析效率低下的物理和化学因素。 即将进行的实验本质上是多学科的，汇集了光谱学、自组装单层研究、扫描探针显微镜和化学分离的想法。 这项工作的实际影响将导致更快、更完整的分离，以用于分析和制备目的。