Sensitivity to NMR detection

The hydrogen nucleus is the most sensitive to NMR detection in absolute terms, although less sensitive, in relative terms, than tritium. The relative sensitivity... 

Tritium has, despite its radioactivity, several features in common to Both nuclei have spin-5 and natural abundance levels that are very low, exceedingly so in the case of H. The latter also has a much higher sensitivity to NMR detection than Over the last 20 years, NMR spectroscopy of solids has been developed into a very powerful technique [4] with applications covering a wide span of interests. Therefore, the possibility exists of developing NMR spectroscopy of solids in an analogous manner, providing the even more demanding safety requirements can be met. 

As well as having a nuclear spin I = j tritium has a high nuclear magnetic moment which is responsible for the magnetogyric constant being larger than for any other nucleus, as also is its sensitivity to NMR detection, 21% higher than that for At 11.7 T,... 

One of the main advantages of FT spectrometers is that, since the FID is in digital form, we can repeat the excitation/detection process a number of times and all the resulting scans can be added and the FT performed on the resultant FID. In this way, we can improve the signal-to-noise ratio and can detect nuclei which are not very abundant (e.g. C) or have low sensitivity to NMR (see Section 4.2). These nuclei could not have been detected on the older continuous wave instruments, as the spectrum was the result of a single scan, obtained as one of the frequency or magnetic held were varied while keeping the other constant. 

NMR spectral measurements have been applied to the investigation of conformational equilibria in many saturated systems. Because of the sensitivity of the P nucleus to NMR detection, P NMR is of great practical importance, providing valuable information supporting the H and C spectral measurements. 

Although the technology of an MRI scanner is rather sophisticated it does what we have seen other NMR spectrometers do it detects protons Thus MRI IS especially sensitive to biological materials such as... 

Several problems m basic methodologies have persisted over the 25 years since F-NMR spectroscopy was first apphed to a biochemical question Most hmiting IS that of NMR sensitivity High substrate concentrabons, relative to the naturally occumng biological levels, are required for NMR detection Although most NMR studies use millimolar and somebmes submilhmolar concenbatrons, many bio molecules exist at micromolar or lower levels... 

NMR methods can be applied to give quantitative determination of initiator-derived and other end groups and provide a wealth of information on the polymerization process. They provide a chemical probe of the detailed initiation mechanism and a greater understanding of polymer properties. The main advantage of NMR methods over alternative techniques for initiator residue detection is that NMR signals (in particular nC NMR) are extremely sensitive to the structural environment of the initiator residue. This means that functionality formed by tail addition, head addition, transfer to initiator or primary radical termination, and various initiator-derived byproducts can be distinguished. 

An important consideration for making NMR and MRI suitable for applications in chemical engineering is to provide for flexibility in handling samples of various sizes, materials, shapes or temperatures, while ensuring sufficiently high NMR detection sensitivity. In this chapter, we present a novel technique known as NMR and MRI remote detection [11,12], which addresses these problems in a fundamental fashion, as well as a few examples where remote detection has been applied successfully. 

In order to use Eqs. (2.6.1) and (2.6.2) to estimate the sensitivity gain obtained by remote detection, knowledge of the relative sensitivity of the detector and the encoding circuit, A, is required. Here we discuss the sensitivity of an rf coil detector as an example, because all the experiments presented in this text use inductive detection at high field. The signal-to-noise ratio of inductive NMR detection can be approximated by the following simplified equation [12] ... 

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