Nuclear magnetic resonance spectroscopy has been widely used in many laboratories. Today, let's talk about the basic knowledge of nuclear magnetic resonance spectroscopy with New Horizon Biology.

  Nuclear magnetic resonance (NMR for short) is a Spectroscopy method used to detect and identify the molecular structure and physical properties of material samples. Nuclear magnetic resonance spectroscopy, ultraviolet absorption spectroscopy, infrared absorption spectroscopy, and mass spectrometry are known as the "four spectra". They are one of the most powerful tools for qualitative analysis of the composition and structure of various organic and inorganic substances, and can also be used for quantitative analysis.

  Nuclear magnetic resonance, like ultraviolet and infrared absorption spectra, is a transition of microscopic particles at different energy levels after absorbing electromagnetic waves. The UV and infrared absorption spectra show molecular absorption wavelengths of 200-400nm and 2.5-25, respectively μ After the radiation of m, it causes transitions of electrons in the molecule and atomic vibrational energy levels, respectively. In the nuclear magnetic resonance spectrum, the wavelength is very long (about 106-109 μ m. In the RF region, electromagnetic waves with frequencies of the order of megahertz and very low energy irradiate molecules, which will not cause vibrations or rotational energy level transitions of the molecules, let alone electronic energy level transitions. But this electromagnetic wave can interact with magnetic atomic nuclei in a strong magnetic field, causing magnetic atomic nuclei to undergo magnetic energy level resonance transitions in an external magnetic field, thereby generating absorption signals. The absorption of radio frequency electromagnetic wave radiation by this type of atomic nucleus is called nuclear magnetic resonance spectroscopy.

So do you know the principle of nuclear magnetic resonance spectroscopy?

  In a strong magnetic field, the magnetism inherent in the atomic nuclei and electronic energy of certain elements is split into two or more quantized energy levels. By absorbing electromagnetic radiation at an appropriate frequency, transitions can occur between the generated magnetic induced energy levels. In a magnetic field, molecules or atomic nuclei with nuclear magnetism absorb the energy difference between two energy levels during the transition from a low energy state to a high energy state, resulting in resonance spectra that can be used to determine the number, type, and relative position of certain atoms in a molecule.