Effects of pulse strength, width, and sample spinning speed on the spectral spin diffusion of multiquantum coherences of spin-32 quadrupolar nuclei

Prevention of spinning induced sample deterioration during long time solid state NMR experiments of quadrupolar spin systems

A simple solution is proposed to prevent a solid state polycrystalline sample from deterioration during long time high speed spinning experiments in solid state NMR. It is found that if a certain percentage ( approximately 40% volume) of polyethylene glycol (PEG, (HO-CH(2)-(CH(2)-O-CH(2)-)(n)-CH(2)-OH)(n)) is mixed with the sample that are subject to deterioration, the quality of the sample can be maintained for a long time under high speed spinning for a few days or longer, sufficient for multi-dimensional and/or low-sensitivity experiments. Both 1D and 2D experimental results are shown to support this idea.