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 (13)C 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 (13)C-transmitter offset. When compared to conventional, broadband (1)H-(13)C 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 (13)C-(13)C homonuclear correlation experiments to obtain a faster and more sensitive characterization of biological solids.