Coherence selection in double CP MAS NMR spectroscopy.
Applications of double cross-polarization (CP) magic-angle spinning (MAS) NMR spectroscopy, via (1)H/(15)N and then (15)N/(13)C coherence transfers, for (13)C coherence selection are demonstrated on a (15)N/(13)C-labeled N-acetyl-glucosamine (GlcNAc) compound. The (15)N/(13)C coherence transfer is very sensitive to the settings of the experimental parameters. To resolve explicitly these parameter dependences, we have systematically monitored the (13)C{(15)N/(1)H} signal as a function of the rf field strength and the MAS frequency. The data reveal that the zero-quantum coherence transfer, with which the (13)C effective rf field is larger than that of the (15)N by the spinning frequency, would give better signal sensitivity. We demonstrate in one- and two-dimensional double CP experiments that spectral editing can be achieved by tailoring the experimental parameters, such as the rf field strengths and/or the MAS frequency.
Yang
Jen-Hsien
JH
Institute of Chemistry, Academia Sinica, 128, Yen-Chiu-Yuan Road, Sec. 2, Nankang, Taipei 11529, Taiwan, ROC.
Chou
Fang-Chieh
FC
Tzou
Der-Lii M
DL
D000465:Algorithms; D003198:Computer Simulation; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008956:Models, Chemical; D013113:Spin Labels
D013113:Spin Labels