Line narrowing in H-1 NMR of powdered organic solids with TOP-CT-MAS experiments at ultra-fast MAS

The residual broadening observed in H-1 spectra of rigid organic solids at natural abundance under 111 kHz magic angle spinning (MAS) is typically a few hundred Hertz. Here we show that refocusable and non-refocusable interactions contribute roughly equally to this residual at high-fields (21.14 T), and suggest that the removal of the non-refocusable part will produce significant increase in spectral resolution. To this end, we demonstrate an experiment for the indirect acquisition of constant-time experiments at ultra-fast MAS (CT-MAS) which verifies this hypothesis. The combination of this experiment with the two-dimensional one pulse (TOP) transformation reduces the experimental time to a fraction of the original cost while retaining the narrowing effects. Results obtained with TOP-CT-MAS at 111 kHz MAS on a sample of beta-AspAla yield up to 30% higher resolution spectra than the equivalent one-pulse experiment, in less than 10 min. (C) 2019 Published by Elsevier Inc.


Published in:
Journal Of Magnetic Resonance, 305, 131-137
Year:
Aug 01 2019
Publisher:
San Diego, ACADEMIC PRESS INC ELSEVIER SCIENCE
ISSN:
1090-7807
1096-0856
Keywords:
Laboratories:




 Record created 2019-08-03, last modified 2019-08-07


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