Band-Selective 1H-13C Cross-Polarization in Fast Magic Angle Spinning Solid-State NMR Spectroscopy

A magic angle spinning (MAS) NMR technique to transfer polarization from protons to a specific set of the C-13 spins is introduced for the study of biomolecular samples in the solid-state. Ultrafast (>60 kHz) MAS and low irradiation rf fields are used to achieve band-selective Hartmann-Hahn cross-polarization (CP) between the whole proton bath and carbons whose resonances are close to the C-13-transmitter offset. When compared to conventional, broadband H-1-C-13 CP, the band-selective experiment can be established without any loss of sensitivity when polarizing the aliphatic signals of a protein sample, and with a significant gain when polarizing carbonyls, This scheme can be used as a building block in 2D C-13-C-13 homonuclear correlation experiments to obtain a faster and more sensitive characterization of biological solids.