Experimental aspects of proton NMR spectroscopy in solids using phase-modulated homonuclear dipolar decoupling
In this paper we demonstrate experimentally that the continuously phase-modulated homonuclear decoupling sequence DUMBO-1 is suitable for high-resolution proton NMR spectroscopy of rigid solids. Over a wide range of experimental conditions, we show on the model sample L-alanine as well as on small peptides that proton linewidths of less than 0.5 ppm can be obtained under DUMBO-1 decoupling. In particular the DUMBO-1 sequence yields well resolved proton spectra both at slow and fast MAS. The DUMBO-1 decoupling scheme can in principle be inserted in any multi-nuclear or multi-dimensional solid-state NMR experiment which requires a high-resolution H-1 dimension. An example is provided with the C-13-H-1 MAS-J-HMQC experiment. (C) 2003 Elsevier Science (USA). All rights reserved.