Application of the Quadrupolar Carr–Purcell–Meiboom–Gill Pulse Train for Sensitivity Enhancement in Deuteron NMR of Liquid Crystals
✍ Scribed by R.S. Prosser; N.J. Heaton; G. Kothe
- Publisher
- Elsevier Science
- Year
- 1996
- Tongue
- English
- Weight
- 176 KB
- Volume
- 112
- Category
- Article
- ISSN
- 1064-1866
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✦ Synopsis
Deuteron ( 2 H) NMR has emerged as a well-established tech-Such a spectrum, whose resolution is proportional to the rotor period, will be partially averaged by the spinning. Nev-nique in the study of molecular structure and dynamics in liquid crystals. Because 2 H NMR spectra and relaxation rates are ertheless, the spectra are not only sensitive to the type and time scale of motions but can be acquired over a greater typically characterized solely by the well-defined nuclear quadrupole interaction, the connection between what is measured range of pulse separation times due to the increased sensitivity (4). One might expect further sensitivity improvements and the desired orientational or dynamic property is particularly clear. However, a major drawback of 2 H NMR is the inherently by the combination of 1 H-2 H cross polarization (6). However, because of the relatively long 1 H T 1 relaxation times, poor sensitivity. This limitation is particularly severe in situations where the molecule (or macromolecule) of interest is this approach has found limited applications.
One can also extend the FID by employing a train of refocus-dilutely concentrated in its liquid-crystalline host (for example, an integral membrane protein in a biological membrane). This ing pulses. In many cases, the resulting echo train may be used in place of the single FID to evaluate the total spectral intensity, article focuses on sensitivity improvements that can be obtained in liquid crystals by appending a Carr-Purcell-Meiboom-Gill resulting in improved signal-to-noise. This scheme has been used successfully by Allerhand and Cochran in high-resolution (CPMG) pulse train (1, 2) to the 2 H multipulse experiment (i.e., quadrupolar-echo, inversion-recovery, or Jeener-Broe-13 C NMR of liquids (7) and by Ross and others in 93 Nb (8), 13