液体样品对核磁图谱质量影响因素探讨

Factors Affecting Spectra Quality of Nuclear Magnetic Resonance of Liquid Sample

结合样品核磁测试结果,以具体实例的形式,总结了核磁样品分析的基本要求,分析了核磁管和氘代试剂的选择、样品制备及pH值等因素对核磁测试结果的影响,并提出了样品最优测试条件:核磁管管体内外表面要足够光洁均匀,在高温条件下,优先选用升温核磁管.尽量选择小支封装氘代试剂,降低水峰的影响,并且应考虑样品的性质,避免试剂与测试样品发生反应.样品必须与溶剂充分混合均匀,样品量要在溶液粘度与灵敏度之间做好平衡.在分析与氧、氮和硫共价相连的氢原子时,应该选择恰当的pH溶液.以上研究结果可以为其它样品核磁测试提供借鉴指导.

The basic requirements of obtaining high-quality nuclear magnetic resonance(NMR)spectra were summarized.The selection of nuclear magnetic tube and deuterium solvent,the sample preparation and pH value,were separately discussed:the surface of the NMR tubes should be smooth enough,tubes with high degree of thermal shock resistances and low expansion coefficient should be the selected priority under the high temperature conditions.A small branch of deuterium solvent should be chosen to reduce the impact of water peaks,and the nature of the sample should be considered to avoid solvent reacting with the test sample.Direct transfer should be the first choice for sample transfer into the NMR tube.The sample must be fully homogeneously mixed with the solvent and the sample quantity should be balanced between solution viscosity and sensitivity.An appropriate pH solution is required for the analysis of hydrogen atoms covalently bounded to oxygen,nitrogen,and sulfur.The above results can be the general guidance for the NMR sample preparation.