Basic principles of NMR

This equation depicts a basic principle of NMR and the experimentally observed quantity. 

Before describing the application of Nuclear magnetic resonance (NMR) spectroscopy to potentized homeopathic drugs we would first discuss the basic principles of NMR spectroscopy. This spectroscopy is a powerful tool providing structural information about molecules. Like UV-visible and infra red spectrometry, NMR spectrometry is also a form of absorption spectrometry. Nuclei of some isotopes possess a mechanical spin and the total angular momentum depends on the nuclear spin, or spin number 1. The numerical value of I is related to the mass number and the atomic number and may be 0, Vi, 1 etc. The medium of homeopathic... 

The aim of this text is to introduce the fascinating topic of the hyphenation of chromatographic separation techniques with nuclear magnetic resonance spectroscopy to an interested readership with a background either in organic, pharmaceutical or medical chemistry. The basic principles of NMR spectroscopy, as well as those of separation science, should previously be known to the reader. 

It is assumed that most readers will be familiar with the basic principles of NMR. However, for completeness and to define some of the terms that will be used in this chapter it is useful to give a brief overview of the principles. Excellent texts are available to provide more detail (18,19). 

The basic principle of NMR imaging was firstly introduced by Lauterbur in (Lauterbur 1973). The spatial resolution is obtained by a magnetic field gradient. A static magnetic field Bq is superimposed by a magnetic field gradient G. The frequency co is shifted and the spatial coordinate (voxel) corresponds to the resonance frequency of the signal ... 

This article provides a description of the basic principles of NMR spectroscopy. The many applications of this technique, which make it indispensable as a tool for the analytical chemist, are described in subsequent articles, which also include discussion of advanced techniques such as the NMR of solids, multidimensional NMR, and MRI. 

After a brief introduction of the basic principles of NMR, the one-dimensional (ID) and two-dimensional (2D) methods that have been applied to viscoelastic materials will be reviewed. NMR imaging which can be considered as a special form of multidimensional NMR will be introduced by discussing principles and image contrast. Illustrative examples of NMR imaging to elastomer materials are given. 

The basic principles of NMR are the same for solution and solid state measurements however, in order to obtain high-resolution solid state... 

Basic Principles of nmr-Spectroscopy of Oriented Molecules The Spin Hamiltonian... 

This chapter will be restricted to discussing solution NMR studies of polymers. For an excellent description of solid-state NMR techniques, the reader should first consult Chapter 2.07 of this comprehensive, by Saalwachter and Spiess. In the next section, some basic principles of NMR will be presented, followed by a discussion of ID-, 2D-, and 3D-NMR principles, techniques, and the information to be gained from each technique. The last seaion will be dedicated to examples of how these techniques can be used to leam about polymer struaures, including monomer composition, stereosequence effects, monomer sequence effects, short-chain branching, chain end structure, dendrimer stracture, and polymer branching, and other polymer defect structures. 

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