Optimizing Decoupler Pulses for CP/MAS NMR

The ¹³C line width of protonated carbons, the signal-to-noise ratio and often the resolution in a CPMAS spectrum depends on effective high power proton decoupling during the acquisition time. A convenient sample to optimize the decoupling power or pulses for ¹³C CPMAS NMR is glycine, as the line width of the methylene carbon is very sensitive to the quality of the decoupling. The figure below shows such an optimization of the pulse widths used in TPPM (Two Pulse Phase Modulation) decouipling. The data were collected at 11.7 T.