Abstract
Substantial resolution and sensitivity enhancements of solid-state H-1 detected N-14 HMQC NMR spectra at very fast MAS rates up to 80 kHz, in a 1 mm MAS rotor, are presented. Very fast MAS enhances the H-1 transverse relaxation time and efficiently decouples the H-1-N-14 interactions, both effects leading to resolution enhancement. The micro-coil contributes to the sensitivity increase via strong N-14 rf fields and high sensitivity per unit volume. H-1-N-14 HMQC 2D spectra of glycine and glycyl-L-alanine at 70 kHz MAS at 11.7 T are observed in a few minutes with a sample volume of 0.8 mu L. (C) 2010 Elsevier Inc. All rights reserved.