Factors Affecting Spectra Quality of Nuclear Magnetic Resonance of Liquid Sample

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.