Studies of minute quantities of natural abundance molecules using 2D heteronuclear correlation spectroscopy under 100 kHz MAS: CP-HSQC approach

The use of ultrafast MAS realizes ¹H indirect detection of heteronuclear correlations of rigid solids. The ¹H indirect detection, which has been routinely used in solution NMR for decades, drastically enhances sensitivity, allowing rapid measurement of ¹H/¹³C correlations even in natural abundance samples. The ¹H/¹³C magnetization transfer mediated by J-coupling is utilized in solution NMR, however, J-based transfer in rigid solids is rather inefficient due to the short ¹H T₂ relaxation times. Instead of J-coupling, here we demonstrate ¹H indirect detection combined with cross-polarization (CP).

CP-based ¹H/¹³C HSQC pulse sequence

f-Met-Leu-Phe-OH tripeptide（in natural abundance)

Organically functionalized mesoporous silica nanoparticles in natural abundance

Reference

Y. Nishiyama, T. Kobayashi, M. Malon, D. Singappuli-Arachchige, I.I. Slowing, M. Pruski, Solid State Nucl. Magn. Reson. 66-67 (2015) 56-61.