Hartmann-Hahn 2D-map to optimize the RAMP-CPMAS NMR experiment for pharmaceutical materials
Copyright © 2012 John Wiley & Sons, Ltd.
| Publié dans: | Magnetic resonance in chemistry : MRC. - 1985. - 50(2012), 2 vom: 01. Feb., Seite 159-68 |
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| Auteur principal: | |
| Autres auteurs: | , , , |
| Format: | Article en ligne |
| Langue: | English |
| Publié: |
2012
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| Accès à la collection: | Magnetic resonance in chemistry : MRC |
| Sujets: | Journal Article Research Support, Non-U.S. Gov't NMR RAMP-CPMAS pharmaceutical materials solid-state NMR Protons Adamantane PJY633525U Glycine plus... |
| Résumé: | Copyright © 2012 John Wiley & Sons, Ltd. Cross polarization-magic angle spinning (CPMAS) is the most used experiment for solid-state NMR measurements in the pharmaceutical industry, with the well-known variant RAMP-CPMAS its dominant implementation. The experimental work presented in this contribution focuses on the entangled effects of the main parameters of such an experiment. The shape of the RAMP-CP pulse has been considered as well as the contact time duration, and a particular attention also has been devoted to the radio-frequency (RF) field inhomogeneity. (13)C CPMAS NMR spectra have been recorded with a systematic variation of (13)C and (1)H constant radiofrequency field pair values and represented as a Hartmann-Hahn matching two-dimensional map. Such a map yields a rational overview of the intricate optimal conditions necessary to achieve an efficient CP magnetization transfer. The map also highlights the effects of sweeping the RF by the RAMP-CP pulse on the number of Hartmann-Hahn matches crossed and how RF field inhomogeneity helps in increasing the CP efficiency by using a larger fraction of the sample. In the light of the results, strategies for optimal RAMP-CPMAS measurements are suggested, which lead to a much higher efficiency than constant amplitude CP experiment |
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| Description: | Date Completed 29.06.2015 Date Revised 03.11.2014 published: Print-Electronic Citation Status MEDLINE |
| ISSN: | 1097-458X |
| DOI: | 10.1002/mrc.3798 |