Applications of Size and Charge Resolved 2D-NMR

尺寸和电荷分辨 2D-NMR 的应用

• 批准号: 9528530
• 负责人: Charles Johnson
• 金额: $ 44.78万
• 依托单位: University of North Carolina at Chapel Hill
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-04-01 至 1999-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9528530&HistoricalAwards=false
• 关键词: Applications; Size; Charge; Resolved; 2D

With the support of the Experimental Physical Chemistry Program, Prof. Charles S. Johnson of the University of North Carolina at Chapel Hill will pursue a number of research objectives: 1) he will expand the capabilities of Diffusion Order Nuclear Magnetic Resonance Spectroscopy (DOSY), so that it can be used to study systems with very small diffusion coefficients. This will require very large magnetic field gradients, and Johnson plans on exploiting the large fringe fields of the superconducting magnet for the pulsed field gradient NMR. 2) He plans on measuring molecular weight distributions of fluoropolymers in supercritical carbon dioxide, an environmentally benign solvent; this will require the design of a high pressure instrument. 3) Johnson will develop heteronuclear DOSY, and 4) he will make improvements on electrophoretic NMR techniques using Mobility Ordered 2-dimensional NMR spectroscopy, or MOSY. DOSY and electrophoretic NMR allow the measurement of molecular diffusion coefficients as a function of the chemical shifts of the various species present in a mixture. This new work will extend considerably the range of diffusion coefficients which can be measured, while also providing better sensitivity and resolution. Supercritical carbon dioxide is a viable replacement for aqueous and organic solvent systems, especially the ozone-depleting chlorofluorocarbons. The research effort in fluoropolymers in supercritical fluids should prove critical to furthering the basic understanding of the chemistry and dynamics of these solution systems.

在实验物理化学项目的支持下，北卡罗来纳大学教堂山分校的Charles S. Johnson教授将追求一些研究目标：1)他将扩展扩散阶核磁共振波谱（DOSY）的能力，使其可以用于研究具有非常小扩散系数的系统。这将需要非常大的磁场梯度，约翰逊计划利用超导磁体的大边缘场来进行脉冲场梯度核磁共振。2)他计划测量含氟聚合物在超临界二氧化碳（一种环保溶剂）中的分子量分布；这就需要设计一种高压仪器。3) Johnson将开发异核DOSY， 4)他将使用迁移率有序二维核磁共振波谱（MOSY）改进电泳核磁共振技术。DOSY和电泳核磁共振允许测量分子扩散系数，作为混合物中存在的各种物质的化学位移的函数。这项新工作将大大扩展可以测量的扩散系数的范围，同时也提供更好的灵敏度和分辨率。超临界二氧化碳是一种可行的替代水和有机溶剂系统，特别是臭氧消耗氯氟烃。超临界流体中含氟聚合物的研究工作对于进一步了解这些溶液体系的化学和动力学至关重要。