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Sensitivity Enhancement in Two‐Dimensional Solid‐State NMR Spectroscopy by Transverse Mixing
Author(s) -
Tycko Robert
Publication year - 2004
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.200301208
Subject(s) - transverse plane , spectroscopy , magic angle spinning , nuclear magnetic resonance spectroscopy , chemistry , solid state nuclear magnetic resonance , polarization (electrochemistry) , analytical chemistry (journal) , mixing (physics) , magic angle , molecular physics , pulse sequence , nuclear magnetic resonance , materials science , physics , stereochemistry , chromatography , structural engineering , quantum mechanics , engineering
The sensitivity of two‐dimensional (2D) 13 C– 13 C solid‐state NMR spectroscopy under magic‐angle spinning (MAS) is shown to be enhanced by the use of transverse polarization transfer in place of the conventional longitudinal polarization transfer. Experimental results are reported for 2D spectroscopy of a 20‐residue, filament‐forming peptide derived from the E. coli RecA protein, containing five uniformly 13 C‐labeled residues, performed at 14.1 T with high‐speed MAS and with finite‐pulse radio‐frequency‐driven recoupling of dipolar interactions in the mixing period. Significant sensitivity enhancements observed at short mixing periods result from a more rapid build‐up of cross‐peaks under transverse mixing than under longitudinal mixing and from the ${\sqrt{2}}$ gain inherent in 2D measurements in which both orthogonal transverse polarization components in the t 1 period contribute to each free‐induction decay signal detected in the t 2 period.