知识点5-核磁共振实验简介

Solvent
acetone
acetonitrile benzene carbon tetrachloride chloroform dimethylsulfoxide water methanol methylene chloride
Baidu Nhomakorabea
d (ppm)
2.05 1.93 7.15 7.25 2.49 4.82 4.84, 3.30 5.32
固定磁场强度，通过连续改变电磁辐射 的频率，产生共振，称为扫频法； 固定电磁辐射的频率，通过连续改变磁 场的强度，产生共振，称为扫场法；
4.4. 1H NMR SOlvents
v v
Chemical Shifts for Typical SOlvents NMR spectra are usually obtained by dissolving the sample in an appropriate solvent. Because the solvent is present in much higher concentration than the sample, protons in the solvent would overwhelm the resonance peaks for the sample. For this reason, deuterated solvents are used in NMR spectroscopy. Completely deuterated solvents are very difficult to make and expensive. In almost all cases, residual protons in the deuterated solvent will cause a resonance peak (or peaks) to appear in the spectrum. The following table shows the chemical shift values for the more common solvents used for 1H NMR spectroscopy.
1．永久磁铁、电磁铁、超 导磁铁。 2 ．射频发射器： 线圈垂 直于外磁场，发射电磁辐 射信号： 60MHz、90MHz 、200MHz ……。 3 ．射频接受器 ：当质子 吸收能量发生能级跃迁时， 在感应线圈中产生毫伏级 信号，经放大，检波后记 录成谱图。 4．样品管：外径5mm的玻璃管,测量过程 中旋转, 磁场作用均匀。