This is NYSBC standard data sets and pulse programs for 1H-13C/15N cross polarization with an optional 13C/15N 90deg pulse followed by 13C/15N acquisition with 1H decoupling. The pulse program has power safety limitations specific for the particular probe. The pulse program CP90_15N_3.2EF750.nysbc, CP90_13C_3.2EF750.nysbc ramp shape file tancn_100_SCALE and include file power_intro.incl are located in the dataset directory.
To minimized heating of conductive samples, we recommend using an Efree/lowE probe. However, a combination of frictional heating from spinning and RF heating on long pulses on both channel may cause substantial sample heating and temperature gradient across the sample even in an Efree probe. The heating may damage the sample. The heating and temperature gradient across the rotor may substantially compromise the precision of measurements and data fitting.
https://aip.scitation.org/doi/10.1063/1.1680061 Proton‐enhanced NMR of dilute spins in solids, A. Pines, M. G. Gibby, and J. S. Waugh, J. Chem. Phys. 59, 569 (1973)
https://www.ncbi.nlm.nih.gov/pubmed/10868566?dopt=Abstract Heating of samples induced by fast magic-angle spinning, Brus, J., Solid State Nucl. Magn. Reson. 16, 151–160 (2000).
https://onlinelibrary.wiley.com/doi/abs/10.1002/mrc.4450 Heating and temperature gradients of lipid bilayer samples induced by RF irradiation in MAS solid-state NMR experiments, Wang, J., Zhang, Z., Zhao, W., Wang, L. & Yang, J., Magn. Reson. Chem. 54, 753–759 (2016).
https://www.biorxiv.org/content/10.1101/566729v1.full TmDOTP : An NMR- based Thermometer for Magic Angle Spinning NMR Experiments Dongyu Zhang, Boris Itin, Ann E. McDermott; preprinted
CP experiments require long simultaneous medium to high power pulses on 1H and X channels. Adjust the probe power length and safety limitations in the pulse sequence to follow your probe specifications. When in doubt, contact the manufacturer.
Use the experiment to measure 1H and 15N power levels and optimized CP conditions and decoupling.
The experiments were performed with crystallized n/a glycine and u-15N,13C-labeled-N-acetyl-valine