Resolution enhancement in 13C and 15N magic-angle turning experiments with TPPM decoupling.
Many solid-state spectra have been shown to have problems related to the poor proton decoupling of carbon nuclei in methylene groups under conditions of slow magic-angle turning. Two-pulse phase-modulation (TPPM) decoupling during the 2D PHORMAT chemical shift separation experiment is shown to be more effective in comparison to that obtainable at much higher spin rates using conventional CW decoupling. TPPM decoupling can also alleviate similar inadequacies when observing the 15N nucleus, particularly with NH2 groups. This is demonstrated in the 15N resonances of fully labeled l-arginine hydrochloride, where a line narrowing of about a factor of two was observed at moderate rotation rates. This significant advantage was also obtained at turning frequencies as low as 500 Hz.
Department of Chemistry, University of Utah, Salt Lake City, Utah, 84112-0850, USA.
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McGeorge
D W
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Alderman
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Grant
D016880:Anisotropy; D001120:Arginine / Q000737:chemistry*; D002247:Carbon Isotopes; D007089:Image Enhancement; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008757:Methylglucosides / Q000737:chemistry*; D015394:Molecular Structure; D009587:Nitrogen Isotopes; D013113:Spin Labels
D002247:Carbon Isotopes; D008757:Methylglucosides; D009587:Nitrogen Isotopes; D013113:Spin Labels; C027020:methylglucoside; D001120:Arginine